CA2024477C - Method and apparatus for providing breathing gas to a person, especially during treatment of sleep apnea - Google Patents
Method and apparatus for providing breathing gas to a person, especially during treatment of sleep apneaInfo
- Publication number
- CA2024477C CA2024477C CA002024477A CA2024477A CA2024477C CA 2024477 C CA2024477 C CA 2024477C CA 002024477 A CA002024477 A CA 002024477A CA 2024477 A CA2024477 A CA 2024477A CA 2024477 C CA2024477 C CA 2024477C
- Authority
- CA
- Canada
- Prior art keywords
- flow rate
- person
- set forth
- gas
- airway
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
- A61M16/20—Valves specially adapted to medical respiratory devices
- A61M16/201—Controlled valves
- A61M16/202—Controlled valves electrically actuated
- A61M16/203—Proportional
- A61M16/204—Proportional used for inhalation control
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
- A61M16/0057—Pumps therefor
- A61M16/0066—Blowers or centrifugal pumps
- A61M16/0069—Blowers or centrifugal pumps the speed thereof being controlled by respiratory parameters, e.g. by inhalation
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
- A61M16/021—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes operated by electrical means
- A61M16/022—Control means therefor
- A61M16/024—Control means therefor including calculation means, e.g. using a processor
- A61M16/026—Control means therefor including calculation means, e.g. using a processor specially adapted for predicting, e.g. for determining an information representative of a flow limitation during a ventilation cycle by using a root square technique or a regression analysis
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
- A61M16/0057—Pumps therefor
- A61M16/0066—Blowers or centrifugal pumps
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
- A61M16/0003—Accessories therefor, e.g. sensors, vibrators, negative pressure
- A61M2016/0015—Accessories therefor, e.g. sensors, vibrators, negative pressure inhalation detectors
- A61M2016/0018—Accessories therefor, e.g. sensors, vibrators, negative pressure inhalation detectors electrical
- A61M2016/0021—Accessories therefor, e.g. sensors, vibrators, negative pressure inhalation detectors electrical with a proportional output signal, e.g. from a thermistor
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
- A61M16/0003—Accessories therefor, e.g. sensors, vibrators, negative pressure
- A61M2016/003—Accessories therefor, e.g. sensors, vibrators, negative pressure with a flowmeter
- A61M2016/0033—Accessories therefor, e.g. sensors, vibrators, negative pressure with a flowmeter electrical
- A61M2016/0036—Accessories therefor, e.g. sensors, vibrators, negative pressure with a flowmeter electrical in the breathing tube and used in both inspiratory and expiratory phase
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
- A61M16/0003—Accessories therefor, e.g. sensors, vibrators, negative pressure
- A61M2016/003—Accessories therefor, e.g. sensors, vibrators, negative pressure with a flowmeter
- A61M2016/0033—Accessories therefor, e.g. sensors, vibrators, negative pressure with a flowmeter electrical
- A61M2016/0039—Accessories therefor, e.g. sensors, vibrators, negative pressure with a flowmeter electrical in the inspiratory circuit
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M2205/00—General characteristics of the apparatus
- A61M2205/15—Detection of leaks
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M2205/00—General characteristics of the apparatus
- A61M2205/35—Communication
- A61M2205/3546—Range
- A61M2205/3561—Range local, e.g. within room or hospital
Abstract
An improved methodology and apparatus for the treatment of sleep apnea through application of alternating high and low level positive airway pressure within the airway of the patient with the high and low airway pressure being coordinated with the spontaneous respiration of the patient.
Description
BACKGROUND OF THE INVENTION
The sleep apnea syndrome afflicts an estimated 1% to 3% of the general population and is due to episodic upper airway obstruction during sleep. Those afflicted with sleep apnea experience sleep fragmentation and intermittent, complete or nearly complete cessation of ventilation during sleep with potentially severe degrees of oxyhemoglobin unsaturation. These features may be translated clinically into debilitating daytime sleepiness, cardiac disrhythmias, pulmonary-artery hypertension, congestive heart failure and cognitive disfunction. Other sequelae of sleep apnea include right ventricular dysfunction with cor pulmonale, carbon dioxide retention during wahefulness as well as during sleep, and continuous reduced arterial oxygen tension. Hypersomnolent sleep apnea patients may be at rish for excessive mortality from these factors as well as by an elevated risk for accidents while driving and/or operating potentially dangerous equipment.
~o Although details of the pathogenesis of upper airway obstruction in sleep apnea patients have not been fully defined, it is generally accepted that the mechanism includes either anatomic or functional abnormalities of the upper airway which result in increased air flow resistance. Such abnormalities may include narrowing of the upper airway due to suction forces evolved during inspiration, the effect of gravity pulling the tongue back to appose the pharyngeal wall, and/or insufficient muscle tone in the upper airway dilator muscles. It has also ~' 2~24477 been hypothesized that a mechanism responsible for the known association between obesity and sleep apnea is excessive soft tissue in the anterior and lateral neck which applies sufficient pressure on internal structures to narrow the airway.
Ine treatment of sleep apnea has included such surgical interventions as uvalopalatopharyngoplasty, gastric surgery for obesity, and maxillo-facial reconstruction. Another mode of surgical intervention used in the treatment of sleep apnea is tracheostomy. These treatments constitute major undertakings with considerable rish of post-operative morbidity if not mortality. Pharmacologic therapy has in general been di5appoin~ing,~ especially in patients with more than mild sleep apnea. In addition, side effects from the pharmacologic agents that have been used are frequent. Thus, medical practitioners continue to seek non-intrusive modes of treatment for sleep apnea with high success rates and high patient compliance including, for example in cases relating to obesity, weight loss through a regimen of exercise and regulated diet.
~ ecent work in the treatment of sleep apnea has included the use of continuous positive airway pressure (CPAP) to maintain the airway of the patient in a continuously open state during sleep. For example, U.S. patent 4,655,213 and Australian patent AU-B-83901/82 both disclose sleep apnea treatments based on continuous positive airway pressure applied within the airway of the patient.
Also of interest is U.S. patent 4,773,411 which discloses a method and apparatus for ventilatory treatment characterized as airway pressure release ventilation and which provides a substantially constant elevated airway pressure with periodic short term reductions of the elevated airway pressure to a pressure magnitude no less than ambient atmospheric pressure.
Publications pertaining to the application of CPAP in treatment of sleep apnea include the following:
1. Llndsay, DA, Issa FG, and Sullivan C.E. ~Mechanisms of Sleep Desaturation in Chronic Airflow Limitation Studied with Nasal Continuous Positive Airway Pressure (CPAP), ~Am Rev Respir Dis, 1982; 125: p.112.
Z. ~anders MH, Moore SE, Eveslage J. ~GPAP via nasal mask: A
treatment for occlusive sleep apnea,~ Chest, 1983; 83:
pp. 144-145.
3. Sullivan C~, Berthon-Jones M, Issa FG. ~Remission of severe obesity-hypoventilation syndrome after short-term treatment during sleep with continuous positive airway pressure,~ Am Rev Respir Dis, 1983; 128: pp. 177-181.
The sleep apnea syndrome afflicts an estimated 1% to 3% of the general population and is due to episodic upper airway obstruction during sleep. Those afflicted with sleep apnea experience sleep fragmentation and intermittent, complete or nearly complete cessation of ventilation during sleep with potentially severe degrees of oxyhemoglobin unsaturation. These features may be translated clinically into debilitating daytime sleepiness, cardiac disrhythmias, pulmonary-artery hypertension, congestive heart failure and cognitive disfunction. Other sequelae of sleep apnea include right ventricular dysfunction with cor pulmonale, carbon dioxide retention during wahefulness as well as during sleep, and continuous reduced arterial oxygen tension. Hypersomnolent sleep apnea patients may be at rish for excessive mortality from these factors as well as by an elevated risk for accidents while driving and/or operating potentially dangerous equipment.
~o Although details of the pathogenesis of upper airway obstruction in sleep apnea patients have not been fully defined, it is generally accepted that the mechanism includes either anatomic or functional abnormalities of the upper airway which result in increased air flow resistance. Such abnormalities may include narrowing of the upper airway due to suction forces evolved during inspiration, the effect of gravity pulling the tongue back to appose the pharyngeal wall, and/or insufficient muscle tone in the upper airway dilator muscles. It has also ~' 2~24477 been hypothesized that a mechanism responsible for the known association between obesity and sleep apnea is excessive soft tissue in the anterior and lateral neck which applies sufficient pressure on internal structures to narrow the airway.
Ine treatment of sleep apnea has included such surgical interventions as uvalopalatopharyngoplasty, gastric surgery for obesity, and maxillo-facial reconstruction. Another mode of surgical intervention used in the treatment of sleep apnea is tracheostomy. These treatments constitute major undertakings with considerable rish of post-operative morbidity if not mortality. Pharmacologic therapy has in general been di5appoin~ing,~ especially in patients with more than mild sleep apnea. In addition, side effects from the pharmacologic agents that have been used are frequent. Thus, medical practitioners continue to seek non-intrusive modes of treatment for sleep apnea with high success rates and high patient compliance including, for example in cases relating to obesity, weight loss through a regimen of exercise and regulated diet.
~ ecent work in the treatment of sleep apnea has included the use of continuous positive airway pressure (CPAP) to maintain the airway of the patient in a continuously open state during sleep. For example, U.S. patent 4,655,213 and Australian patent AU-B-83901/82 both disclose sleep apnea treatments based on continuous positive airway pressure applied within the airway of the patient.
Also of interest is U.S. patent 4,773,411 which discloses a method and apparatus for ventilatory treatment characterized as airway pressure release ventilation and which provides a substantially constant elevated airway pressure with periodic short term reductions of the elevated airway pressure to a pressure magnitude no less than ambient atmospheric pressure.
Publications pertaining to the application of CPAP in treatment of sleep apnea include the following:
1. Llndsay, DA, Issa FG, and Sullivan C.E. ~Mechanisms of Sleep Desaturation in Chronic Airflow Limitation Studied with Nasal Continuous Positive Airway Pressure (CPAP), ~Am Rev Respir Dis, 1982; 125: p.112.
Z. ~anders MH, Moore SE, Eveslage J. ~GPAP via nasal mask: A
treatment for occlusive sleep apnea,~ Chest, 1983; 83:
pp. 144-145.
3. Sullivan C~, Berthon-Jones M, Issa FG. ~Remission of severe obesity-hypoventilation syndrome after short-term treatment during sleep with continuous positive airway pressure,~ Am Rev Respir Dis, 1983; 128: pp. 177-181.
4. ~ullivan CE, Issa FG, Berthon-Jones M, Eveslage. ~Reversal of obstructive sleep apnea by contnuous positive airway pressure applied through the nares,~ Lancet, 1981; 1:
pp. ~6Z-:365.
202447~
pp. ~6Z-:365.
202447~
5. Sullivan CE, Berthon-Jones M. Issa FG. ~Treatment of obstructive apnea with continuous positive airway pressure applied through the nose.~ Am Rev Respir Dis, 198Z;
125: p.107. Annual Meeting Abstracts.
B. Rapoport DM, Sorkin B, Garay SM, Goldring RM. "Reversal of the 'Pichwichian Syndrome' by long-term use of nocturnal nasal-airway pressure,~ N Engl J. Med, 1982; 307:
pp.931-933.
7. Sanders MH, Holzer BC, Pennoch BE. ~The effect of nasal CPAP on various sleep apnea patterns,~ Chest, 1983; 84:
p.336. Presented at the Annual Meeting of the American College of Chest Physicians, Chicago IL, October 1983.
Although CPAP has been found to be very effective and well accepted, it suffers from some of the same limitations, although to a lesser degree, as do the surgery options; specifically a 2~ significant proportion of sleep apnea patients do not tolerate CPAP well. Thus, development of other viable non-invasive therapies has been a continuing objective in the art.
BRIEF SUMMARY OF THE INVENTION
rhe present invention contemplates a novel and improved method for treatment of sleep apnea as well as novel methodology and apparatus for carrying out such improved treatment method.
The invention contemplates the treatment of sleep apnea through application of pressure at variance with ambient atmospheric pressure within the upper airway of the patient in a manner to promote dilation of the airway to thereby relieve upper airway occlusion during sleep.
~ n one embodlment of the invention, positive pressure is applied alternately at relatively higher and lower pressure levels within the airway of the patient so that the pressure-induced force applied to dilate the patient's airway is alternately a larger and a smaller magnitude dilating force.
The higher and lower magnitude positive pressures are initiated by spontaneous patient respiration with the higher magnitude pressure being applied during inspiration and the lower magnitude pressure being applied during expiration.
Ihe inventlon further contemplates a novel and improved apparatus which is operable in accordance with a novel and improved method to provide sleep apnea treatment. More specifically, a flow generator and an adjustable pressure controller supply air flow at a predeterminsd, adjustable pressure to the airway of a patient through a flow transducer.
The flow transducer generates an output signal which is then conditioned to provide a signal proportional to the instantaneous flow rate of air to the patient. The instantaneous flow rate signal is fed to a low pass filter which passes only a signal indicative of the average flow rate over time. The average flow rate signal typically would be expected 202~477 to be a value representing a positive flow as the system is lihely to have at least minimal leahage from the patient circuit (e.g. small leaks about the perimeter of the respiration mask worn by the patient). The average flow signal is indicative of such leahage because the summation of all other components of flow over time must be essentially zero since inspiration flow must equal expiration flow volume over time, that is, over a period of time the volume of air breathed in equals the volume of the gases breathed out.
~ otn the instantaneous flow signal and the average flow rate signal are fed to an inspiration/expiration decision module which is, in its simplest form, a comparator that continually compares the input signals and provides a corresponding drive signal to the pressure controller. In general, when the instantaneous flow exceeds average flow, the patient is inhaling and the drive signal supplied to the pressure controller sets the pressure controller to deliver air, at a preselected elevated pressure, to the airway of the patient. Similarly, when the instantaneous flow rate is less than the average flow rate, the patient is exhaling and the decision circuitry thus provides a drive signal to set the pressure controller to provide a relatively lower magnitude of pressure in the airway of the patient. The patient's airway thus is maintained open by alternating higher and lower magnitudes of pressure which are applicd during spontaneous inhalation and exhalation, respectively.
As has been noted, some sleep apnea patients do not tolerate standard CPAP therapy. Specifically, approximately 25%
of patients cannot tolerate CPAP due to the attendant discomfort. CPAP mandates equal pressures during both inhalation and exhalation. The elevated pressure during both phases of breathing may create difficulty in exhaling and the sensation of an inflated chest. However, we have determined that although both inspiratory and expiratory air flow resistances in the airway are elevated during sleep preceding the onset of apnea, the airway flow resistance may be less during expiration than during inspiration. Thus it follows that the bi-level CPAP therapy of our invention as characterized above may be sufficient to maintain pharyngeal patency during expiration even though the pressure applied during expiration is not as high as that needed to maintain pharyngeal patency during inspiration. In addition, some patients may have increased upper airway resistance primarily during inspiration with resulting adverse physiologic consequences. Thus, our invention also contemplates applying elevated pressure only during inhalation thus eliminating the need for global ~inhalation and exhalation) increases in airway pressure. The relatively lower pressure applied during expiration may in some cases approach or equal ambient pressure. The lower pressure applied in the airway during expiration enhances patient tolerance by alleviating some of the uncomfortable sensations normally associated with CPAP.
~ nder prior CPAP therapy, pressures as high as 15 cm H20 have been required, and some patients on nasal CPAP thus have been needlessly exposed to unnecessarily high expiratory pressures with the attendant discomfort and elevated mean airway pressure, and theoretic rish of barotrauma. Our invention permits independent application of a higher inspiratory airway pressure in conjunction with a lower expiratory airway pressure in order to provide a therapy which is better tolerated by the 25% of the patient population which does not tolerate CPAP
therapy, and which may be safer in the other 75% of the patient population.
As has been noted hereinabove, the switch between higher and lower pressure magnitudes can be controlled by spontaneous patient respiration, and the patient thus is able to independently govern respiration rate and volume. As has been also noted, the invention contemplates automatic compensation for system leakage whereby nasal mask fit and air flow system integrity are of less consequence than in the prior art. In addition to the benefit of automatic leak compensation, other ~o important benefits of the invention include lower mean airway pressures for the patient and enhanced sa-fety, comfort and tolerance.
It is accordingly one object of the present invention to provide a novel and improved method for treatment of sleep apnea.
A further object of the invention to provide a novel and 202447~
improved apparatus which is operable according to a novel methodology in carrying out such a treatment for sleep apnea.
Another object of the invention is to provide a method and apparatus for treating sleep apnea by application of alternately high and low magnitudes of pressure in the airway of the patient with the high and low pressure magnitudes being initiated by spontaneous patient respiration.
Another object of the invention is to provide an apparatus for generating alternately high and low pressure gas flow to a consumer of the gas with the higher and lower pressure flows being controlled by comparison of the instantaneous flow rate to the gas consumer with the average flow rate to the consumer, which average flow rate may include leakage from the system, and whereby the apparatus automatically compensates for system leakage.
These and other objects and further advantages of the invention will be more readily appreciated upon consideration of the following detailed description and accompanying drawings, in which:
Flg. 1 is a functional bloch diagram of an apparatus according to the instant invention which is operable according to the method of the instant invention;
Fig. 2 is a functional block diagram showing an alternative embodiment of the invention;
fig. 3 is a functional bloch diagram of the Estimated Leak Computer of Fig. 2; and Fig. 4 is a frontal elevation of a control panel for the apparatus of this invention.
lhere is generally indicated at 10 in Fig. 1 an apparatus according to one presently preferred embodiment of the instant invention and shown in the form of a functional block diagram.
Apparatus 10 is operable according to a novel process which is another aspect of the instant invention for delivering breathing gas such as air alternately at relatively higher and lower pressures (i.e., equal to or above ambient atmospheric pressure~
to a patient 12 for treatment of the condition known as sleep apnea.
Apparatus 10 comprises a gas flow generator 14 (e.g., a blower) which receives breathing gas from any suitable source, a pressurized bottle 16 or the ambient atmosphere, for example.
The gas flow from flow generator 14 is passed via a delivery conduit 20 to a breathing appliance such as a mask 22 of any suitable known construction which is worn by patient 12. The mask 22 may preferably be a nasal mask or a full face mask 22 as shown. Other breathing appliances which may be used in lieu of a mask include nasal cannulae, an endotracheal tube, or any other suitable appliance for interfacing between a source of breathing gas and a patient.
The mask 22 includes a suitable exhaust port means, schematically indicated at 24, for exhaust of breathing gases 5 during expiration. Exhaust port 24 preferably is a continuously open port which imposes a suitable flow resistance upon exhaust gas flow to permit a pressure controller 26, located in line with conduit 20 between flow generator 14 and mash 22, to control the pressure of air flow within conduit 20 and thus 10 within the airway of the patient 12. For example, exhaust port 24 may be of sufficient cross-sectional flow area to sustain a continuous exhaust flow of approximately 15 liters per minute.
The flow via exhaust port 24 is one component, and typically the major component of the overall system leakage, which is an important parameter of system operation. In an alternative embodiment to be discussed hereinbelow, it has been found that a non-rebreathing valve may bv substituted for the continuously open port 24.
1he pressure controller 26 is operative to control the pressure of breathing gas within the conduit 20 and thus within the airway of the patient. Pressure controller 26 is located preferably, although not necessarily, downstream of flow generator 14 and may take the form of an adjustable valve which z5 provides a flow path which is open to the ambient atmosphere via a restricted opening, the valve being adjustable to maintain a constant pressure drop across the opening for all flow rates and thus a constant pressure within conduit 20.
- ~ 202~477 Also interposed in line with conduit 20, preferably downstream of pressure controller 26, is a suitable flow transducer 28 which generates an output signal that is fed as indicated at 29 to a flow signal conditioning circuit 30 for derivation of a signal proportional to the instantaneous flow rate of breathing gas within conduit 20 to the patient.
It will be appreciated that flow generator 14 is not 1~ necessarily a positive displacement device. It may be, for example, a blower which creates a pressure head within conduit 20 and provides air flow only to the extent required to maintain that pressure head in the presence of patient breathing cycles, the exhaust opening 24, and action of pressure controller 26 as above described. Accordingly, when the patient is exhaling, peak exhalation flow rates from the lungs may far exceed the flow capacity of exhaust port 24. As a result, exhalation gas backflows within conduit 20 through flow transducer 28 and toward pressure controller 26, and the instantaneous flow rate signal from transducer 28 thus will vary widely within a range from relatively large positive (i.e. toward the patient) flow to relatively large negative (i.e. from the patient) flow.
The instantaneous flow rate signal from flow signal conditioning circuitry 30 is fed as indicated at 32 to a decision module 34, a known comparator circuit for example, and is additionally fed as indicated at 36 to a low pass filter 38.
Low pass filter 38 has a cut-off frequency low enough to remove from the instantaneous flow rate input signal most variations in the signal which are due to normal breathing. Low pass filter 38 also has a long enough time constant to ensure that spurious signals, aberrant flow patterns and peak instantaneous flow rate values will not dramatically affect system average flow. That is, the time constant of low pass filter 38 is selected to be long enough that it responds slowly to the instantaneous flow rate signal input. Accordingly, most instantaneous flow rate input signals which could have a large impact on system average flow in the short term have a much smaller impact over a longer term, largely because such instantaneous flow rate signal components will tend to cancel over the longer term. For example, peah instantaneous flow rate values will tend to be alternating relatively large positive and negative flow values corresponding to peak inhalation and exhalation flow achieved by the patient during normal spontaneous breathing. The output of low pass filter 38 thus is a signal which is proportional to the average flow in the system, and this is typically a positive flow which corresponds to average system leakage (including flow ~o from exhaust 24) since, as noted, inhalation and exhalation flow cancel for all practical purposes.
rhe average flow signal output from the low pass filter 38 is fed as indicated at 40 to decision circuitry 34 where the ~5 instantaneous flow rate signal is continually compared to the system average flow signal. The output of the decision circuitry 34 is fed as a drive signal indicated at 42 to control the pressure controller 26. The pressure magnitude of breathing 20~477 gas within conduit 20 thus is coordinated with the spontaneous breathing effort of the patient 12, as follows.
~nen the patient begins to inhale, the instantaneous flow rate signal goes to a positive value above the positive average flow signal value. Detection of this increase in decision circuitry 34 is sensed as the start of patient inhalation. The output signal from decision circuitry 34 is fed to pressure controller 26 which, in response, provides higher pressure gas flow within conduit 20 and thus higher pressure within the airway of the patient 12. This is the higher magnitude pressure value of our bi-level CPAP system and is referred to hereinbelow as IPAP (inhalation positive airway pressure). During inhalation, the flow rate within conduit 20 will increase to a maximum and then decrease as inhalation comes to an end.
At the start of exhalation, air flow into the patient's lungs is nil and as a result the instantaneous flow rate signal will be less than the average flow rate signal which, as noted is a relatively constant positive flow value. The decision circuitry 34 senses this condition as the start of exhalation and provides a drive signal to pressure controller 26 which, in response, provides gas flow within conduit 20 at a lower pressure which is the lower magnitude pressure value of the bi-level CPAP system, referred to hereinbelow as EPAP
(exhalation positive airway pressure). As has been noted hereinabove the range of EPAP pressures may include ambient atmospheric pressure. When the patient again begins spontaneous 20~4477 inhalation, the instantaneous flow rate signal again increases over the average flow rate signal, and the decision circuitry once again feeds a drive signal to pressure controller 26 to reinstitute the IPAP pressure.
System operation as above specified requires at least periodic comparison of the input signals 32 and 40 by decision circuitry 34. Where this or other operations are described herein as continual, the scope of meaning to be ascribed includes both continuous (i.e. uninterrupted) or periodic (i.e.
at discrete intervals).
As has ~een noted, the system 10 has a built-in controlled leahage via exhaust port 24 thus assuring that the average flow signal will be at least a small positive flow. During inhalation, the flow sensed by the flow transducer will be the sum of exhaust flow via port 24 and all other system leakage downstream of transducer 28, and inhalation flow within the airway of the patient 12. Accordingly, during inhalation the instantaneous flow rate signal as conditioned by conditioning module 30, will reliably and consistently reflect inhalation flow exceeding the average flow rate signal. During exhalation, the flow within conduit 20 reverses as exhalation flow from the lungs of the patient far exceeds the flow capacity of exhaust port 24. Accordingly, exhalation air backflows within conduit 20 past transducer 28 and toward pressure controller 26. Since pressure controller 26 is operable to maintain set pressure, it will act in response to flow coming from both the patient and the flow generator to open an outlet port sufficiently to accommodate the additional flow volume and thereby maintain the specified set pressure as determined by action of decision circuitry 34.
tn both the inhalation and exhalation cycle phases, the pressure of the gas within conduit 20 exerts a pressure within the airway of the patient to maintain an open airway and thereby alleviate airway constriction.
In practice, it may be desirable to provide a slight offset in the switching level within decision circuitry 34 with respect to the average flow rate signal, so that the system does not prematurely switch from the low pressure exhalation mode to the higher pressure inhalation mode. That is, a switching setpoint offset in the positive direction from system average flow may be provided such that the system will not switch to the IPAP mode until the patient actually exerts a significant spontaneous inspiratory effort of a minimum predetermined magnitude. This will ensure that the initiation of inhalation is completely spontaneous and not forced by an artificial increase in airway pressure. A similar switching setpoint offset may be provided when in the IPAP mode to ensure the transition to the lower pressure EPAP mode will occur before the flow rate of air into the lungs of the patient reaches zero (i.e. the switch to EPAP
occurs Slightly before the patient ceases inhalation.) This will ensure that the patient will encounter no undue initial resistance to spontaneous exhalation.
202~477 ~ rom the above description, it will be seen that a novel method of treating sleep apnea is proposed according to which the airway pressure of the patient is maintained at a higher positive pressure during inspiration and a relatively lower pressure during expiration, all without interference with the spontaneous breathing of the patient. The described apparatus is operable to provide such treatment for sleep apnea patients by providing a flow of breathing gas to the patient at positive pressure, and varying the pressure of the air flow to provide alternately high and low pressure within the airway of the patient coordinated with the patient's spontaneous inhalation and exhalation.
1o provlde pressure control, the flow rate of breathing gas to the patient is detected and processed to continually provide a signal which is proportional to the instantaneous breathing gas flow rate in the system. The instantaneous flow rate signal is further processed to eliminate variations attributable to normal patient respiration and other causes thus generating a signal which is proportional to the average or steady state system gas flow. The average flow signal is continually compared with the instantaneous flow signal as a means to detect the state of the patient's spontaneous breathing versus average z5 system flow. When instantaneous flow exceeds the average flow, the patient is inhaling, and in response the pressure of gas flowing to the patient is set at a selected positive pressure, to provide a corresponding positive pressure within the airway 202~77 of the patient. When comparison of the instantaneous flow rate signal with the average flow signal indicates the patient is exhaling, as for example when the instantaneous flow signal indicates flow equal to or less than the average flow, the pressure of breathing gas to the patient is adjusted to a selected lower pressure to provide a corresponding lower pressure within the airway of the patient.
ln an alternative embodiment of the invention as shown in Figs. 2 and 3, the low pass filter 38 is replaced by an estimated leah computer which includes a low pass filter as well as other functional elements as shown in Fig. 3. The remainder of the system as shown in Fig. 2 is similar in most respects to the system shown in Fig. 1. Accordingly, like elements are identified by like numbers, and the description hereinabove of Fig. 1 embodiment also applies generally to Fig. 2.
~ y uslng the operative capability of the estimated leak computer 50, as described hereinbelow, it is possible to adjust the reference signal which is fed to decision circuitry 34 on a breath by breath basis rather than merely relying on long term average system flow. To distinguish this new reference signal from average system flow it will be referred to hereinbelow as the estimated leak flow rate signal or just the estimated leak signal As was noted hereinabove, the average system flow rate reference signal changes very slowly due to the long time 2~2~477 constant of the low pass filter 38. This operative feature was intentionally incorporated to avoid disturbance of the reference signal by aberrant instantaneous flow rate signal inputs such as erratic breathing patterns. While it was possible to minimize the impact of such aberrations on the average flow rate reference signal, the average flow signal did nevertheless change, although by small increments and only very slowly in response to disturbances. Due to the long time constant of the low pass filter, such changes in the reference signal even if transitory could last for a long time.
Additionally, even a small change in the reference signal could produce a very significant effect on system triggering.
For example, since the objective is to trigger the system to the IPAP mode when inhalation flow just begins to go positive, small changes in the reference signal could result in relatively large changes in the breathing effort needed to trigger the system to the IPAP mode. In some instances the change in reference signal could be so great that with normal breathing effort the patient would be unable to trigger the system. For example, if the system were turned on before placement of the mask on the face of the patient, the initial free flow of air from the unattached mask could result in a very large magnitude positive value for initial average system flow. If such value were to exceed the maximum inspiratory flow rate achieved in spontaneous respiration by the patient, the system would never trigger between the IPAP and EPAP modes because the decision circuitry would never see an instantaneous flow rate signal greater than - ` 202~4~7 the average flow rate signal, at least not until a sufficient number of normal breathing cycles after application of the mash to the patient to bring the reference signal down to a value more closely commensurate with the actual system leak in operation. As has been noted, with the low pass filter this could take a rather long time, during which time the patient would be breathing spontaneously against a uniform positive pressure. This would be tantamount to conventional CPAP and not at all in keeping with the present invention.
In addltion to the embodiment based on a reference signal derived from estimated leak flow rate on a breath by breath basis which is controlled totally by spontaneous patient breathing, two further modes of operation also are envisioned, one being spontaneous/timed operation in which the system automatically triggers to the IPAP mode for just long enough to initiate patient inspiration if the system does not sense inspiratory effort within a selected time after exhalation begins. To accomplish this, a timer is provided which is reset 2~ at the beginning of each patient inspiration whether the inspiratory cycle was triggered spontaneously or by the timer itself. Thus, only the start of inspiration is initiated by the timer. The rest of the operating cycle in this mode is controlled by spontaneous patient breathing and the circuitry of the system to be described.
~ furtner mode of operation is based purely on timed operation of the system rather than on spontaneous patient breathing effort, but with the timed cycles coordinated to spontaneous patient breathing.
Referring to Fig. 3, the estimated leah computer 50 includes the low pass filter 38' as well as other circuits which are operative to make corrections to the estimated leak flow rate signal based on on-going analysis of each patient breath.
A further circuit is provided which is operative to adjust the estimated leak flow rate signal quickly after major changes in tO system flow such as when the blower has been running prior to the time when the mask is first put on the patient, or after a major leak the system has either started or has been shut off.
The low pass filter 38' also includes a data storage capability whose function will be described hereinbelow.
The low pass filter 38' operates substantially as described above with reference to Fig. 1 in that it provides a long term average of system flow which is commensurate with steady state 20- system leakage including the flow capacity of the exhaust port 24. This long term average is operative in the Fig. 3 embodiment to adjust the estimated leah flow rate reference signal only when system flow conditions are changing very slowly.
To provide breath by breath analysis and adjustment of the reference signal, a differential amplifier 52 receives the instantaneous flow rate signal as indicated at 54, and the estimated leah signal output from low pass filter 38' as indicated at 56.
The output of differential amplifier 52 is the difference between instantaneous flow rate and estimated leak flow rate, or in other words estimated instantaneous patient flow rate. This will be clear upon considering that instantaneous flow is the sum of patient flow plus actual system leahage. The estimated patient flow signal output from differential amplifier 52 is provided as indicated at 58 to a flow integrator 60 which integrates estimated patient flow breath by breath beginning and ending with the trigger to IPAP. Accordingly, an additional input to the flow integrator 60 is the IPAP/EPAP state signal as indicated at 62. The IPAP/EPAP state signal is the same as the drive signal provided to pressure controller Z6; that is, it is a signal indicative of the pressure state, as between IPAP and EPAP, of the system. The state signal thus may be used to mark the beginning and end of each breath for purposes of breath by breath integration by integrator 60.
lf the estimated leak flow rate signal from low pass filter 38' is equal to the true system leah flow rate, and if the patient's inhaled and exhaled volumes are identical for a given breath (i.e. total positive patient flow equals total negative patient flow for a given breath), then the integral calculated by integrator 60 will be zero and no adjustment of estimated leak flow rate will result. When the integral calculated by integrator 60 is non-zero, the integral value in the form of an 2024~77 output signal from integrator 60 is provided as indicated at 64 to a sample and hold module 66. Of course, even with a zero value integral, an output signal may be provided to module 66, but the ultimate result will be no adjustment of the estimated leak flow rate signal.
A non-zero integral value provided to module 66 is further provided to module 38' as indicated at 68 with each patient breath by operative action of the IPAPIEPAP state signal upon module 66 as indicated at 70. The effect of a non-zero integral value provided to module 38' is an adjustment of the estimated leak flow rate signal proportional to the integral value and in the direction which would reduce the integral value towards zero on the next breath if all other conditions remain the same.
With this system, if the patient's net breathing cycle volume is zero, and if the system leak flow rate changes, the integrator circuit will compensate for the change in leak flow rate by incremental adjustments to the estimated leak flow rate 2~ within about ten patient breaths.
rhe integrator circuit 60 also will adjust the estimated leak flow rate signal in response to non-zero net volume in a patient breathing cycle. It is ! not unusual for a patient's breathing volume to be non-zero. For example, a patient may inhale slightly more on each breath than he exhales over several breathing cycles, and then follow with a deeper or fuller exhalation. In this case, the integrator circuit would adjust ~ 2024477 the estimated leak flow rate signal as if the actual system leah rate had changed; however, since the reference signal correction is only about one tenth as large as would be required to make the total correction in one breath, the reference signal will not change appreciably over just one or two breaths. Thus, the integrator circuit accommodates both changes in system leahage and normal variations in patient breathing patterns. The integrator circuit normally would be active, for example, during rapid patient breathing.
1~
~ n end exhalation module 74 is operative to calculate another data component for use in estimating the system leah flow rate as follows. The module 74 monitors the slope of the instantaneous flow rate wave form. When the slope value is near zero during exhalation (as indicated by the state signal input 76) the indication is that the flow rate is not changing. If the slope of the instantaneous flow rate signal wave form remains small after more than one second into the respiratory phase, the indication is that exhalation has ended and that the 2U net flow rate at this point thus is the leak flow rate.
However, if estimated patient flow rate is non-zero at the same time, one component of the instantaneous flow rate signal must be patient flow.
~ hen these conditions are met, the circuit adjusts the estimated leah flow rate slowly in a direction to move estimated patient flow rate toward zero to conform to instantaneous patient flow conditions expected at the end of exhalation. jThe ~- 2024477 adjustment to sstimated leak flow rate is provided as an output from module 74 to low pass filter 38' as indicated at 80. When this control mechanism takes effect, it disables the breath by breath volume correction capability of integrator circuit 60 for that breath only.
The output of module 74 is a time constant control signal which is provided to low pass filter 38' to temporarily shorten the time constant thereof for a sufficient period to allow the estimated leak flow rate to approach the instantaneous flow rate signal at that specific instant. It will be noted that shortening the low pass filter time constant increases the rapidity with which the low pass filter output (a system average) can adjust toward the instantaneous flow rate signal 1S input.
Another component of estimated leak flow rate control is a gross error detector 8Z which acts when the estimated patient flow rate, provided thereto as indicated at 84, is away from zero for more than about 5 seconds. Such a condition may normally occur, for example, when the flow generator 14 is running before mask 22 is applied to the patient. This part of the control system is operative to stabilize operation quickly after major changes in the leak rate occur.
ln accordance with the above description, it will be seen that low pass filter 38' acts on the instantaneous flow rate signal to provide an output corresponding to average system flow, which is system leahage since patient inspiration and expiration over time constitutes a net positive flow of zero.
With other enhancements, as described, the system average flow can be viewed as an estimate of leakage flow rate.
Ine dltferential amplifier 52 processes the instantaneous flow rate signal and the estimated leak flow rate signal to provide an estimated patient flow rate signal which is integrated and non-zero values of the integral are fed back to module 38' to adjust the estimated leak flow rate signal on a breath by breath ba~is. The integrator 60 is reset by the IPAP/EPAP state signal via connection 62.
~wo circuits are provided which can override the integrator 1~ circuit, including end exhalation detector 74 which provides an output to adjust the time constant of low pass filter 38' and which also is provided as indicated at 86 to reset integrator 60. Gross error detector 82 is also provided to process estimated patient flow rate and to provide an adjustment to 2~ estimated leak flow rate under conditions as specified. The output of module 82 also is utilized as an integrator reset signal as indicated at 86. It will be noted that the integrator 60 is reset with each breath of the patient if, during that breath, it is ultimately overridden by module 74 or 82.
Accordingly, the multiple reset capabilities for integrator 60 as described are required.
In operation, the system may be utilized in a spontaneous 2024477 ~
triggering mode, a spontaneous/timed mode or a purely timed mode of operation. In spontaneous operation, decision circuitry 34 continuously compares the instantaneous flow rate with estimated leak flow rate. If the system is in the EPAP state or mode, it remains there until instantaneous flow rate exceeds estimated leah flow rate by approximately 40 cc per second. When this transition occurs, decision circuitry 34 triggers the system into the IPAP mode for 150 milliseconds. The system will then normally remain in the IPAP mode as the instantaneous flow rate to the patient will continue to increase during inhalation due to spontaneous patient effort and the assistance of the increased IPAP pressure.
After the transition to the IPAP mode in each breath, a temporary offset is added to the estimated leah flow rate reference signal. The offset is proportional to the integral of estimated patient flow rate beginning at initiation of the inspiratory breath so that it gradually increases with time during inspiration at a rate proportional to the patient's inspiratory flow rate. Accordingly, the flow rate level above estimated leak flow needed to keep the system in the IPAP mode during inhalation decreases with time from the beginning of inhalation and in proportion to the inspiratory flow rate. With this enhancement,the longer an inhalation cycle continues, the larger is the reference signal below which instantaneous flow would have to decrease in order to trigger the EPAP mode. For example, if a patient inhales at a constant 500 cc per second until near the end of inspiration, a transition to EPAP will occur when his flow rate drops to about 167 cc per second after one second, or 333 cc per second after two seconds, or 500 cc per second after three seconds, and so forth. For a patient inhaling at a constant 250 cc per second, the triggers would occur at 83, 167 and 250 cc per second at one, two and three seconds into IPAP, respectively.
In this way, the EPAP trigger threshold comes up to meet the inspiratory flow rate with the following benefits. First, it becomes easier and easier to end the inspiration cycle with increasing time into the cycle. Second, if a leah develops which causes an increase in instantaneous flow sufficient to trigger the system into the IPAP mode, this system will automatically trigger back to the EPAP mode after about 3.0 seconds regardless of patient breathing effort. This would allow the volume-based leah correction circuit (i.e. integrator 60) to act as it is activated with each transition to the IPAP
mode. Thus, if a leak develops suddenly, there will be a tendency toward automatic triggering rather than spontaneous operation for a few breaths, but the circuit will not be locked into the IPAP mode.
Upon switching back to the EPAP mode, the trigger threshold will remain above the estimated leah flow rate for approximately 500 milliseconds to allow the system to remain stable in the EPAP mode without switching again while the respective flow rates are changing. After 500 milliseconds, the trigger threshold offset is reset to zero to await the next inspiratory 2024~77 effort.
The normal state for the circuit is for it to remain in the EPAP mode until an inspiratory effort is made by the patient.
The automatic corrections and adjustments to the reference signal are effective to keep the system from locking up in the IPAP mode and to prevent auto-triggering while at the same time providing a high level of sensitivity to inspiratory effort and rapid adjustment for changing leah conditions and breathing patternS, In the spontaneous/timed mode of operation, the system performs exactly as above described with reference to spontaneous operation, except that it allows selection of a 1~ minimum breathing rate to be superimposed upon the spontaneous operating mode. If the patient does not mahe an inspiratory effort within a predetermined time, the system will automatically trigger to the IPAP mode for 200 milliseconds.
The increased airway pressure for this 200 milliseconds will initiate patent inspiration and provide sufficient time that spontaneous patient flow will exceed the reference signal so that the rest of the cycle may continue in the spontaneous mode as above described. The breaths per minute timer is reset by each trigger to IPAP whether the transition was triggered by the 2~ patient or by the timer itself.
ln the timed operating mode, all triggering between IPAP
and EPAP modes is controlled by a timer with a breath per minute control being used to select a desired breathing rate from, for example, 3 to 30 breaths per minute. If feasible, the selected breathing rate is coordinated to the patient's spontaneous breathing rate. The percent IPAP control is used to set the fraction of each breathing cycle to be spent in the IPAP mode.
For example, if the breaths per minute control is set to 10 breaths per minute (6 seconds per breath) and the percent IPAP
control is set to 33%, then the flow generator will spend, in each breathing cycle, two seconds in IPAP and four seconds in EPAp Fig. 4 illustrates a control panel for controlling the system above described and including a function selector switch which includes function settings for the three operating modes of spontaneous, spontaneous/timed, and timed as above described.
The controls for spontaneous mode operation include IPAP and EPAP pressure adjustment controls 90 and 92, respectively.
These are used for setting the respective IPAP and EPAP pressure levels. In the spontaneous/timed mode of operation, controls 90 2~ and 92 are utilized as before to set IPAP and EPAP pressure levels, and breaths per minute control 94 additionally is used to set the minimum desired breathing rate in breaths per minute.
In the timed mode of operation, controls 90, 92 and 94 are effective, and in addition the per cent IPAP control 96 is used to set the time percentage of each breath to be spent in the IPAP mode.
Lighted indicators such as LED's 96, 98 and 100 are also provided to indicate whether the system is in the IPAP or EPAP
state, and to indicate whether in the spontaneous/timed mode of operation the instantaneous state of the system is spontaneous operation or timed operation.
According to the above description there is provided by the instant invention a novel and improved method and apparatus for the treatment of sleep apnea. Of course, we have contemplated various alternative and modified embodiments of the invention of which the above described are exemplary as the presently contemplated best modes for carrying out the invention. Such alternative embodiments would also surely occur to others skilled in the art, once apprised of the invention. For example, it may be desirable to provide a flow compensation signal to pressure controller 26 as indicated at 102 in Fig. 2 to compensate for flow resistance inherent in the circuit; a non-rebreathing valve may be utilized in lieu of exhaust port 24 at mask 22; and the like. Accordingly, it is intended that the invention be construed broadly and limited only by the scope of the claims appended hereto.
125: p.107. Annual Meeting Abstracts.
B. Rapoport DM, Sorkin B, Garay SM, Goldring RM. "Reversal of the 'Pichwichian Syndrome' by long-term use of nocturnal nasal-airway pressure,~ N Engl J. Med, 1982; 307:
pp.931-933.
7. Sanders MH, Holzer BC, Pennoch BE. ~The effect of nasal CPAP on various sleep apnea patterns,~ Chest, 1983; 84:
p.336. Presented at the Annual Meeting of the American College of Chest Physicians, Chicago IL, October 1983.
Although CPAP has been found to be very effective and well accepted, it suffers from some of the same limitations, although to a lesser degree, as do the surgery options; specifically a 2~ significant proportion of sleep apnea patients do not tolerate CPAP well. Thus, development of other viable non-invasive therapies has been a continuing objective in the art.
BRIEF SUMMARY OF THE INVENTION
rhe present invention contemplates a novel and improved method for treatment of sleep apnea as well as novel methodology and apparatus for carrying out such improved treatment method.
The invention contemplates the treatment of sleep apnea through application of pressure at variance with ambient atmospheric pressure within the upper airway of the patient in a manner to promote dilation of the airway to thereby relieve upper airway occlusion during sleep.
~ n one embodlment of the invention, positive pressure is applied alternately at relatively higher and lower pressure levels within the airway of the patient so that the pressure-induced force applied to dilate the patient's airway is alternately a larger and a smaller magnitude dilating force.
The higher and lower magnitude positive pressures are initiated by spontaneous patient respiration with the higher magnitude pressure being applied during inspiration and the lower magnitude pressure being applied during expiration.
Ihe inventlon further contemplates a novel and improved apparatus which is operable in accordance with a novel and improved method to provide sleep apnea treatment. More specifically, a flow generator and an adjustable pressure controller supply air flow at a predeterminsd, adjustable pressure to the airway of a patient through a flow transducer.
The flow transducer generates an output signal which is then conditioned to provide a signal proportional to the instantaneous flow rate of air to the patient. The instantaneous flow rate signal is fed to a low pass filter which passes only a signal indicative of the average flow rate over time. The average flow rate signal typically would be expected 202~477 to be a value representing a positive flow as the system is lihely to have at least minimal leahage from the patient circuit (e.g. small leaks about the perimeter of the respiration mask worn by the patient). The average flow signal is indicative of such leahage because the summation of all other components of flow over time must be essentially zero since inspiration flow must equal expiration flow volume over time, that is, over a period of time the volume of air breathed in equals the volume of the gases breathed out.
~ otn the instantaneous flow signal and the average flow rate signal are fed to an inspiration/expiration decision module which is, in its simplest form, a comparator that continually compares the input signals and provides a corresponding drive signal to the pressure controller. In general, when the instantaneous flow exceeds average flow, the patient is inhaling and the drive signal supplied to the pressure controller sets the pressure controller to deliver air, at a preselected elevated pressure, to the airway of the patient. Similarly, when the instantaneous flow rate is less than the average flow rate, the patient is exhaling and the decision circuitry thus provides a drive signal to set the pressure controller to provide a relatively lower magnitude of pressure in the airway of the patient. The patient's airway thus is maintained open by alternating higher and lower magnitudes of pressure which are applicd during spontaneous inhalation and exhalation, respectively.
As has been noted, some sleep apnea patients do not tolerate standard CPAP therapy. Specifically, approximately 25%
of patients cannot tolerate CPAP due to the attendant discomfort. CPAP mandates equal pressures during both inhalation and exhalation. The elevated pressure during both phases of breathing may create difficulty in exhaling and the sensation of an inflated chest. However, we have determined that although both inspiratory and expiratory air flow resistances in the airway are elevated during sleep preceding the onset of apnea, the airway flow resistance may be less during expiration than during inspiration. Thus it follows that the bi-level CPAP therapy of our invention as characterized above may be sufficient to maintain pharyngeal patency during expiration even though the pressure applied during expiration is not as high as that needed to maintain pharyngeal patency during inspiration. In addition, some patients may have increased upper airway resistance primarily during inspiration with resulting adverse physiologic consequences. Thus, our invention also contemplates applying elevated pressure only during inhalation thus eliminating the need for global ~inhalation and exhalation) increases in airway pressure. The relatively lower pressure applied during expiration may in some cases approach or equal ambient pressure. The lower pressure applied in the airway during expiration enhances patient tolerance by alleviating some of the uncomfortable sensations normally associated with CPAP.
~ nder prior CPAP therapy, pressures as high as 15 cm H20 have been required, and some patients on nasal CPAP thus have been needlessly exposed to unnecessarily high expiratory pressures with the attendant discomfort and elevated mean airway pressure, and theoretic rish of barotrauma. Our invention permits independent application of a higher inspiratory airway pressure in conjunction with a lower expiratory airway pressure in order to provide a therapy which is better tolerated by the 25% of the patient population which does not tolerate CPAP
therapy, and which may be safer in the other 75% of the patient population.
As has been noted hereinabove, the switch between higher and lower pressure magnitudes can be controlled by spontaneous patient respiration, and the patient thus is able to independently govern respiration rate and volume. As has been also noted, the invention contemplates automatic compensation for system leakage whereby nasal mask fit and air flow system integrity are of less consequence than in the prior art. In addition to the benefit of automatic leak compensation, other ~o important benefits of the invention include lower mean airway pressures for the patient and enhanced sa-fety, comfort and tolerance.
It is accordingly one object of the present invention to provide a novel and improved method for treatment of sleep apnea.
A further object of the invention to provide a novel and 202447~
improved apparatus which is operable according to a novel methodology in carrying out such a treatment for sleep apnea.
Another object of the invention is to provide a method and apparatus for treating sleep apnea by application of alternately high and low magnitudes of pressure in the airway of the patient with the high and low pressure magnitudes being initiated by spontaneous patient respiration.
Another object of the invention is to provide an apparatus for generating alternately high and low pressure gas flow to a consumer of the gas with the higher and lower pressure flows being controlled by comparison of the instantaneous flow rate to the gas consumer with the average flow rate to the consumer, which average flow rate may include leakage from the system, and whereby the apparatus automatically compensates for system leakage.
These and other objects and further advantages of the invention will be more readily appreciated upon consideration of the following detailed description and accompanying drawings, in which:
Flg. 1 is a functional bloch diagram of an apparatus according to the instant invention which is operable according to the method of the instant invention;
Fig. 2 is a functional block diagram showing an alternative embodiment of the invention;
fig. 3 is a functional bloch diagram of the Estimated Leak Computer of Fig. 2; and Fig. 4 is a frontal elevation of a control panel for the apparatus of this invention.
lhere is generally indicated at 10 in Fig. 1 an apparatus according to one presently preferred embodiment of the instant invention and shown in the form of a functional block diagram.
Apparatus 10 is operable according to a novel process which is another aspect of the instant invention for delivering breathing gas such as air alternately at relatively higher and lower pressures (i.e., equal to or above ambient atmospheric pressure~
to a patient 12 for treatment of the condition known as sleep apnea.
Apparatus 10 comprises a gas flow generator 14 (e.g., a blower) which receives breathing gas from any suitable source, a pressurized bottle 16 or the ambient atmosphere, for example.
The gas flow from flow generator 14 is passed via a delivery conduit 20 to a breathing appliance such as a mask 22 of any suitable known construction which is worn by patient 12. The mask 22 may preferably be a nasal mask or a full face mask 22 as shown. Other breathing appliances which may be used in lieu of a mask include nasal cannulae, an endotracheal tube, or any other suitable appliance for interfacing between a source of breathing gas and a patient.
The mask 22 includes a suitable exhaust port means, schematically indicated at 24, for exhaust of breathing gases 5 during expiration. Exhaust port 24 preferably is a continuously open port which imposes a suitable flow resistance upon exhaust gas flow to permit a pressure controller 26, located in line with conduit 20 between flow generator 14 and mash 22, to control the pressure of air flow within conduit 20 and thus 10 within the airway of the patient 12. For example, exhaust port 24 may be of sufficient cross-sectional flow area to sustain a continuous exhaust flow of approximately 15 liters per minute.
The flow via exhaust port 24 is one component, and typically the major component of the overall system leakage, which is an important parameter of system operation. In an alternative embodiment to be discussed hereinbelow, it has been found that a non-rebreathing valve may bv substituted for the continuously open port 24.
1he pressure controller 26 is operative to control the pressure of breathing gas within the conduit 20 and thus within the airway of the patient. Pressure controller 26 is located preferably, although not necessarily, downstream of flow generator 14 and may take the form of an adjustable valve which z5 provides a flow path which is open to the ambient atmosphere via a restricted opening, the valve being adjustable to maintain a constant pressure drop across the opening for all flow rates and thus a constant pressure within conduit 20.
- ~ 202~477 Also interposed in line with conduit 20, preferably downstream of pressure controller 26, is a suitable flow transducer 28 which generates an output signal that is fed as indicated at 29 to a flow signal conditioning circuit 30 for derivation of a signal proportional to the instantaneous flow rate of breathing gas within conduit 20 to the patient.
It will be appreciated that flow generator 14 is not 1~ necessarily a positive displacement device. It may be, for example, a blower which creates a pressure head within conduit 20 and provides air flow only to the extent required to maintain that pressure head in the presence of patient breathing cycles, the exhaust opening 24, and action of pressure controller 26 as above described. Accordingly, when the patient is exhaling, peak exhalation flow rates from the lungs may far exceed the flow capacity of exhaust port 24. As a result, exhalation gas backflows within conduit 20 through flow transducer 28 and toward pressure controller 26, and the instantaneous flow rate signal from transducer 28 thus will vary widely within a range from relatively large positive (i.e. toward the patient) flow to relatively large negative (i.e. from the patient) flow.
The instantaneous flow rate signal from flow signal conditioning circuitry 30 is fed as indicated at 32 to a decision module 34, a known comparator circuit for example, and is additionally fed as indicated at 36 to a low pass filter 38.
Low pass filter 38 has a cut-off frequency low enough to remove from the instantaneous flow rate input signal most variations in the signal which are due to normal breathing. Low pass filter 38 also has a long enough time constant to ensure that spurious signals, aberrant flow patterns and peak instantaneous flow rate values will not dramatically affect system average flow. That is, the time constant of low pass filter 38 is selected to be long enough that it responds slowly to the instantaneous flow rate signal input. Accordingly, most instantaneous flow rate input signals which could have a large impact on system average flow in the short term have a much smaller impact over a longer term, largely because such instantaneous flow rate signal components will tend to cancel over the longer term. For example, peah instantaneous flow rate values will tend to be alternating relatively large positive and negative flow values corresponding to peak inhalation and exhalation flow achieved by the patient during normal spontaneous breathing. The output of low pass filter 38 thus is a signal which is proportional to the average flow in the system, and this is typically a positive flow which corresponds to average system leakage (including flow ~o from exhaust 24) since, as noted, inhalation and exhalation flow cancel for all practical purposes.
rhe average flow signal output from the low pass filter 38 is fed as indicated at 40 to decision circuitry 34 where the ~5 instantaneous flow rate signal is continually compared to the system average flow signal. The output of the decision circuitry 34 is fed as a drive signal indicated at 42 to control the pressure controller 26. The pressure magnitude of breathing 20~477 gas within conduit 20 thus is coordinated with the spontaneous breathing effort of the patient 12, as follows.
~nen the patient begins to inhale, the instantaneous flow rate signal goes to a positive value above the positive average flow signal value. Detection of this increase in decision circuitry 34 is sensed as the start of patient inhalation. The output signal from decision circuitry 34 is fed to pressure controller 26 which, in response, provides higher pressure gas flow within conduit 20 and thus higher pressure within the airway of the patient 12. This is the higher magnitude pressure value of our bi-level CPAP system and is referred to hereinbelow as IPAP (inhalation positive airway pressure). During inhalation, the flow rate within conduit 20 will increase to a maximum and then decrease as inhalation comes to an end.
At the start of exhalation, air flow into the patient's lungs is nil and as a result the instantaneous flow rate signal will be less than the average flow rate signal which, as noted is a relatively constant positive flow value. The decision circuitry 34 senses this condition as the start of exhalation and provides a drive signal to pressure controller 26 which, in response, provides gas flow within conduit 20 at a lower pressure which is the lower magnitude pressure value of the bi-level CPAP system, referred to hereinbelow as EPAP
(exhalation positive airway pressure). As has been noted hereinabove the range of EPAP pressures may include ambient atmospheric pressure. When the patient again begins spontaneous 20~4477 inhalation, the instantaneous flow rate signal again increases over the average flow rate signal, and the decision circuitry once again feeds a drive signal to pressure controller 26 to reinstitute the IPAP pressure.
System operation as above specified requires at least periodic comparison of the input signals 32 and 40 by decision circuitry 34. Where this or other operations are described herein as continual, the scope of meaning to be ascribed includes both continuous (i.e. uninterrupted) or periodic (i.e.
at discrete intervals).
As has ~een noted, the system 10 has a built-in controlled leahage via exhaust port 24 thus assuring that the average flow signal will be at least a small positive flow. During inhalation, the flow sensed by the flow transducer will be the sum of exhaust flow via port 24 and all other system leakage downstream of transducer 28, and inhalation flow within the airway of the patient 12. Accordingly, during inhalation the instantaneous flow rate signal as conditioned by conditioning module 30, will reliably and consistently reflect inhalation flow exceeding the average flow rate signal. During exhalation, the flow within conduit 20 reverses as exhalation flow from the lungs of the patient far exceeds the flow capacity of exhaust port 24. Accordingly, exhalation air backflows within conduit 20 past transducer 28 and toward pressure controller 26. Since pressure controller 26 is operable to maintain set pressure, it will act in response to flow coming from both the patient and the flow generator to open an outlet port sufficiently to accommodate the additional flow volume and thereby maintain the specified set pressure as determined by action of decision circuitry 34.
tn both the inhalation and exhalation cycle phases, the pressure of the gas within conduit 20 exerts a pressure within the airway of the patient to maintain an open airway and thereby alleviate airway constriction.
In practice, it may be desirable to provide a slight offset in the switching level within decision circuitry 34 with respect to the average flow rate signal, so that the system does not prematurely switch from the low pressure exhalation mode to the higher pressure inhalation mode. That is, a switching setpoint offset in the positive direction from system average flow may be provided such that the system will not switch to the IPAP mode until the patient actually exerts a significant spontaneous inspiratory effort of a minimum predetermined magnitude. This will ensure that the initiation of inhalation is completely spontaneous and not forced by an artificial increase in airway pressure. A similar switching setpoint offset may be provided when in the IPAP mode to ensure the transition to the lower pressure EPAP mode will occur before the flow rate of air into the lungs of the patient reaches zero (i.e. the switch to EPAP
occurs Slightly before the patient ceases inhalation.) This will ensure that the patient will encounter no undue initial resistance to spontaneous exhalation.
202~477 ~ rom the above description, it will be seen that a novel method of treating sleep apnea is proposed according to which the airway pressure of the patient is maintained at a higher positive pressure during inspiration and a relatively lower pressure during expiration, all without interference with the spontaneous breathing of the patient. The described apparatus is operable to provide such treatment for sleep apnea patients by providing a flow of breathing gas to the patient at positive pressure, and varying the pressure of the air flow to provide alternately high and low pressure within the airway of the patient coordinated with the patient's spontaneous inhalation and exhalation.
1o provlde pressure control, the flow rate of breathing gas to the patient is detected and processed to continually provide a signal which is proportional to the instantaneous breathing gas flow rate in the system. The instantaneous flow rate signal is further processed to eliminate variations attributable to normal patient respiration and other causes thus generating a signal which is proportional to the average or steady state system gas flow. The average flow signal is continually compared with the instantaneous flow signal as a means to detect the state of the patient's spontaneous breathing versus average z5 system flow. When instantaneous flow exceeds the average flow, the patient is inhaling, and in response the pressure of gas flowing to the patient is set at a selected positive pressure, to provide a corresponding positive pressure within the airway 202~77 of the patient. When comparison of the instantaneous flow rate signal with the average flow signal indicates the patient is exhaling, as for example when the instantaneous flow signal indicates flow equal to or less than the average flow, the pressure of breathing gas to the patient is adjusted to a selected lower pressure to provide a corresponding lower pressure within the airway of the patient.
ln an alternative embodiment of the invention as shown in Figs. 2 and 3, the low pass filter 38 is replaced by an estimated leah computer which includes a low pass filter as well as other functional elements as shown in Fig. 3. The remainder of the system as shown in Fig. 2 is similar in most respects to the system shown in Fig. 1. Accordingly, like elements are identified by like numbers, and the description hereinabove of Fig. 1 embodiment also applies generally to Fig. 2.
~ y uslng the operative capability of the estimated leak computer 50, as described hereinbelow, it is possible to adjust the reference signal which is fed to decision circuitry 34 on a breath by breath basis rather than merely relying on long term average system flow. To distinguish this new reference signal from average system flow it will be referred to hereinbelow as the estimated leak flow rate signal or just the estimated leak signal As was noted hereinabove, the average system flow rate reference signal changes very slowly due to the long time 2~2~477 constant of the low pass filter 38. This operative feature was intentionally incorporated to avoid disturbance of the reference signal by aberrant instantaneous flow rate signal inputs such as erratic breathing patterns. While it was possible to minimize the impact of such aberrations on the average flow rate reference signal, the average flow signal did nevertheless change, although by small increments and only very slowly in response to disturbances. Due to the long time constant of the low pass filter, such changes in the reference signal even if transitory could last for a long time.
Additionally, even a small change in the reference signal could produce a very significant effect on system triggering.
For example, since the objective is to trigger the system to the IPAP mode when inhalation flow just begins to go positive, small changes in the reference signal could result in relatively large changes in the breathing effort needed to trigger the system to the IPAP mode. In some instances the change in reference signal could be so great that with normal breathing effort the patient would be unable to trigger the system. For example, if the system were turned on before placement of the mask on the face of the patient, the initial free flow of air from the unattached mask could result in a very large magnitude positive value for initial average system flow. If such value were to exceed the maximum inspiratory flow rate achieved in spontaneous respiration by the patient, the system would never trigger between the IPAP and EPAP modes because the decision circuitry would never see an instantaneous flow rate signal greater than - ` 202~4~7 the average flow rate signal, at least not until a sufficient number of normal breathing cycles after application of the mash to the patient to bring the reference signal down to a value more closely commensurate with the actual system leak in operation. As has been noted, with the low pass filter this could take a rather long time, during which time the patient would be breathing spontaneously against a uniform positive pressure. This would be tantamount to conventional CPAP and not at all in keeping with the present invention.
In addltion to the embodiment based on a reference signal derived from estimated leak flow rate on a breath by breath basis which is controlled totally by spontaneous patient breathing, two further modes of operation also are envisioned, one being spontaneous/timed operation in which the system automatically triggers to the IPAP mode for just long enough to initiate patient inspiration if the system does not sense inspiratory effort within a selected time after exhalation begins. To accomplish this, a timer is provided which is reset 2~ at the beginning of each patient inspiration whether the inspiratory cycle was triggered spontaneously or by the timer itself. Thus, only the start of inspiration is initiated by the timer. The rest of the operating cycle in this mode is controlled by spontaneous patient breathing and the circuitry of the system to be described.
~ furtner mode of operation is based purely on timed operation of the system rather than on spontaneous patient breathing effort, but with the timed cycles coordinated to spontaneous patient breathing.
Referring to Fig. 3, the estimated leah computer 50 includes the low pass filter 38' as well as other circuits which are operative to make corrections to the estimated leak flow rate signal based on on-going analysis of each patient breath.
A further circuit is provided which is operative to adjust the estimated leak flow rate signal quickly after major changes in tO system flow such as when the blower has been running prior to the time when the mask is first put on the patient, or after a major leak the system has either started or has been shut off.
The low pass filter 38' also includes a data storage capability whose function will be described hereinbelow.
The low pass filter 38' operates substantially as described above with reference to Fig. 1 in that it provides a long term average of system flow which is commensurate with steady state 20- system leakage including the flow capacity of the exhaust port 24. This long term average is operative in the Fig. 3 embodiment to adjust the estimated leah flow rate reference signal only when system flow conditions are changing very slowly.
To provide breath by breath analysis and adjustment of the reference signal, a differential amplifier 52 receives the instantaneous flow rate signal as indicated at 54, and the estimated leah signal output from low pass filter 38' as indicated at 56.
The output of differential amplifier 52 is the difference between instantaneous flow rate and estimated leak flow rate, or in other words estimated instantaneous patient flow rate. This will be clear upon considering that instantaneous flow is the sum of patient flow plus actual system leahage. The estimated patient flow signal output from differential amplifier 52 is provided as indicated at 58 to a flow integrator 60 which integrates estimated patient flow breath by breath beginning and ending with the trigger to IPAP. Accordingly, an additional input to the flow integrator 60 is the IPAP/EPAP state signal as indicated at 62. The IPAP/EPAP state signal is the same as the drive signal provided to pressure controller Z6; that is, it is a signal indicative of the pressure state, as between IPAP and EPAP, of the system. The state signal thus may be used to mark the beginning and end of each breath for purposes of breath by breath integration by integrator 60.
lf the estimated leak flow rate signal from low pass filter 38' is equal to the true system leah flow rate, and if the patient's inhaled and exhaled volumes are identical for a given breath (i.e. total positive patient flow equals total negative patient flow for a given breath), then the integral calculated by integrator 60 will be zero and no adjustment of estimated leak flow rate will result. When the integral calculated by integrator 60 is non-zero, the integral value in the form of an 2024~77 output signal from integrator 60 is provided as indicated at 64 to a sample and hold module 66. Of course, even with a zero value integral, an output signal may be provided to module 66, but the ultimate result will be no adjustment of the estimated leak flow rate signal.
A non-zero integral value provided to module 66 is further provided to module 38' as indicated at 68 with each patient breath by operative action of the IPAPIEPAP state signal upon module 66 as indicated at 70. The effect of a non-zero integral value provided to module 38' is an adjustment of the estimated leak flow rate signal proportional to the integral value and in the direction which would reduce the integral value towards zero on the next breath if all other conditions remain the same.
With this system, if the patient's net breathing cycle volume is zero, and if the system leak flow rate changes, the integrator circuit will compensate for the change in leak flow rate by incremental adjustments to the estimated leak flow rate 2~ within about ten patient breaths.
rhe integrator circuit 60 also will adjust the estimated leak flow rate signal in response to non-zero net volume in a patient breathing cycle. It is ! not unusual for a patient's breathing volume to be non-zero. For example, a patient may inhale slightly more on each breath than he exhales over several breathing cycles, and then follow with a deeper or fuller exhalation. In this case, the integrator circuit would adjust ~ 2024477 the estimated leak flow rate signal as if the actual system leah rate had changed; however, since the reference signal correction is only about one tenth as large as would be required to make the total correction in one breath, the reference signal will not change appreciably over just one or two breaths. Thus, the integrator circuit accommodates both changes in system leahage and normal variations in patient breathing patterns. The integrator circuit normally would be active, for example, during rapid patient breathing.
1~
~ n end exhalation module 74 is operative to calculate another data component for use in estimating the system leah flow rate as follows. The module 74 monitors the slope of the instantaneous flow rate wave form. When the slope value is near zero during exhalation (as indicated by the state signal input 76) the indication is that the flow rate is not changing. If the slope of the instantaneous flow rate signal wave form remains small after more than one second into the respiratory phase, the indication is that exhalation has ended and that the 2U net flow rate at this point thus is the leak flow rate.
However, if estimated patient flow rate is non-zero at the same time, one component of the instantaneous flow rate signal must be patient flow.
~ hen these conditions are met, the circuit adjusts the estimated leah flow rate slowly in a direction to move estimated patient flow rate toward zero to conform to instantaneous patient flow conditions expected at the end of exhalation. jThe ~- 2024477 adjustment to sstimated leak flow rate is provided as an output from module 74 to low pass filter 38' as indicated at 80. When this control mechanism takes effect, it disables the breath by breath volume correction capability of integrator circuit 60 for that breath only.
The output of module 74 is a time constant control signal which is provided to low pass filter 38' to temporarily shorten the time constant thereof for a sufficient period to allow the estimated leak flow rate to approach the instantaneous flow rate signal at that specific instant. It will be noted that shortening the low pass filter time constant increases the rapidity with which the low pass filter output (a system average) can adjust toward the instantaneous flow rate signal 1S input.
Another component of estimated leak flow rate control is a gross error detector 8Z which acts when the estimated patient flow rate, provided thereto as indicated at 84, is away from zero for more than about 5 seconds. Such a condition may normally occur, for example, when the flow generator 14 is running before mask 22 is applied to the patient. This part of the control system is operative to stabilize operation quickly after major changes in the leak rate occur.
ln accordance with the above description, it will be seen that low pass filter 38' acts on the instantaneous flow rate signal to provide an output corresponding to average system flow, which is system leahage since patient inspiration and expiration over time constitutes a net positive flow of zero.
With other enhancements, as described, the system average flow can be viewed as an estimate of leakage flow rate.
Ine dltferential amplifier 52 processes the instantaneous flow rate signal and the estimated leak flow rate signal to provide an estimated patient flow rate signal which is integrated and non-zero values of the integral are fed back to module 38' to adjust the estimated leak flow rate signal on a breath by breath ba~is. The integrator 60 is reset by the IPAP/EPAP state signal via connection 62.
~wo circuits are provided which can override the integrator 1~ circuit, including end exhalation detector 74 which provides an output to adjust the time constant of low pass filter 38' and which also is provided as indicated at 86 to reset integrator 60. Gross error detector 82 is also provided to process estimated patient flow rate and to provide an adjustment to 2~ estimated leak flow rate under conditions as specified. The output of module 82 also is utilized as an integrator reset signal as indicated at 86. It will be noted that the integrator 60 is reset with each breath of the patient if, during that breath, it is ultimately overridden by module 74 or 82.
Accordingly, the multiple reset capabilities for integrator 60 as described are required.
In operation, the system may be utilized in a spontaneous 2024477 ~
triggering mode, a spontaneous/timed mode or a purely timed mode of operation. In spontaneous operation, decision circuitry 34 continuously compares the instantaneous flow rate with estimated leak flow rate. If the system is in the EPAP state or mode, it remains there until instantaneous flow rate exceeds estimated leah flow rate by approximately 40 cc per second. When this transition occurs, decision circuitry 34 triggers the system into the IPAP mode for 150 milliseconds. The system will then normally remain in the IPAP mode as the instantaneous flow rate to the patient will continue to increase during inhalation due to spontaneous patient effort and the assistance of the increased IPAP pressure.
After the transition to the IPAP mode in each breath, a temporary offset is added to the estimated leah flow rate reference signal. The offset is proportional to the integral of estimated patient flow rate beginning at initiation of the inspiratory breath so that it gradually increases with time during inspiration at a rate proportional to the patient's inspiratory flow rate. Accordingly, the flow rate level above estimated leak flow needed to keep the system in the IPAP mode during inhalation decreases with time from the beginning of inhalation and in proportion to the inspiratory flow rate. With this enhancement,the longer an inhalation cycle continues, the larger is the reference signal below which instantaneous flow would have to decrease in order to trigger the EPAP mode. For example, if a patient inhales at a constant 500 cc per second until near the end of inspiration, a transition to EPAP will occur when his flow rate drops to about 167 cc per second after one second, or 333 cc per second after two seconds, or 500 cc per second after three seconds, and so forth. For a patient inhaling at a constant 250 cc per second, the triggers would occur at 83, 167 and 250 cc per second at one, two and three seconds into IPAP, respectively.
In this way, the EPAP trigger threshold comes up to meet the inspiratory flow rate with the following benefits. First, it becomes easier and easier to end the inspiration cycle with increasing time into the cycle. Second, if a leah develops which causes an increase in instantaneous flow sufficient to trigger the system into the IPAP mode, this system will automatically trigger back to the EPAP mode after about 3.0 seconds regardless of patient breathing effort. This would allow the volume-based leah correction circuit (i.e. integrator 60) to act as it is activated with each transition to the IPAP
mode. Thus, if a leak develops suddenly, there will be a tendency toward automatic triggering rather than spontaneous operation for a few breaths, but the circuit will not be locked into the IPAP mode.
Upon switching back to the EPAP mode, the trigger threshold will remain above the estimated leah flow rate for approximately 500 milliseconds to allow the system to remain stable in the EPAP mode without switching again while the respective flow rates are changing. After 500 milliseconds, the trigger threshold offset is reset to zero to await the next inspiratory 2024~77 effort.
The normal state for the circuit is for it to remain in the EPAP mode until an inspiratory effort is made by the patient.
The automatic corrections and adjustments to the reference signal are effective to keep the system from locking up in the IPAP mode and to prevent auto-triggering while at the same time providing a high level of sensitivity to inspiratory effort and rapid adjustment for changing leah conditions and breathing patternS, In the spontaneous/timed mode of operation, the system performs exactly as above described with reference to spontaneous operation, except that it allows selection of a 1~ minimum breathing rate to be superimposed upon the spontaneous operating mode. If the patient does not mahe an inspiratory effort within a predetermined time, the system will automatically trigger to the IPAP mode for 200 milliseconds.
The increased airway pressure for this 200 milliseconds will initiate patent inspiration and provide sufficient time that spontaneous patient flow will exceed the reference signal so that the rest of the cycle may continue in the spontaneous mode as above described. The breaths per minute timer is reset by each trigger to IPAP whether the transition was triggered by the 2~ patient or by the timer itself.
ln the timed operating mode, all triggering between IPAP
and EPAP modes is controlled by a timer with a breath per minute control being used to select a desired breathing rate from, for example, 3 to 30 breaths per minute. If feasible, the selected breathing rate is coordinated to the patient's spontaneous breathing rate. The percent IPAP control is used to set the fraction of each breathing cycle to be spent in the IPAP mode.
For example, if the breaths per minute control is set to 10 breaths per minute (6 seconds per breath) and the percent IPAP
control is set to 33%, then the flow generator will spend, in each breathing cycle, two seconds in IPAP and four seconds in EPAp Fig. 4 illustrates a control panel for controlling the system above described and including a function selector switch which includes function settings for the three operating modes of spontaneous, spontaneous/timed, and timed as above described.
The controls for spontaneous mode operation include IPAP and EPAP pressure adjustment controls 90 and 92, respectively.
These are used for setting the respective IPAP and EPAP pressure levels. In the spontaneous/timed mode of operation, controls 90 2~ and 92 are utilized as before to set IPAP and EPAP pressure levels, and breaths per minute control 94 additionally is used to set the minimum desired breathing rate in breaths per minute.
In the timed mode of operation, controls 90, 92 and 94 are effective, and in addition the per cent IPAP control 96 is used to set the time percentage of each breath to be spent in the IPAP mode.
Lighted indicators such as LED's 96, 98 and 100 are also provided to indicate whether the system is in the IPAP or EPAP
state, and to indicate whether in the spontaneous/timed mode of operation the instantaneous state of the system is spontaneous operation or timed operation.
According to the above description there is provided by the instant invention a novel and improved method and apparatus for the treatment of sleep apnea. Of course, we have contemplated various alternative and modified embodiments of the invention of which the above described are exemplary as the presently contemplated best modes for carrying out the invention. Such alternative embodiments would also surely occur to others skilled in the art, once apprised of the invention. For example, it may be desirable to provide a flow compensation signal to pressure controller 26 as indicated at 102 in Fig. 2 to compensate for flow resistance inherent in the circuit; a non-rebreathing valve may be utilized in lieu of exhaust port 24 at mask 22; and the like. Accordingly, it is intended that the invention be construed broadly and limited only by the scope of the claims appended hereto.
Claims (91)
1. A method of providing breathing gas from a source for breathing by a person who is breathing in repeated cycles each including an inspiratory phase and an expiratory phase comprising the steps of:
supplying such breathing gas to the airway of such a person at a positive pressure at least equal to ambient atmospheric pressure to maintain the person's airway at a positive pressure substantially continuously throughout said repeated breathing cycles;
passing such breathing gas through flow measuring means between such a source and the airway of such a person to continually monitor the flow;
responding to said flow measuring means to continually produce signals dependent on the instantaneous flow rate and the average flow rate of such breathing gas flowing between the source and the airway of the person;
passing said signals dependent on said instantaneous flow rate and said average flow rate to means capable of identifying the occurrence of said inspiratory and expiratory phases; and automatically adjusting the pressure of gas passing from said source to said person according to the said occurrence of each said inspiratory and expiratory phase to maintain said positive pressure in the person's airway substantially continuously during a sequence of said inspiratory and said expiratory phases with the magnitude of said positive pressure maintained during each said expiratory phase of said sequence being less than the magnitude of said positive pressure maintained during each immediately preceding inspiratory phase, respectively.
supplying such breathing gas to the airway of such a person at a positive pressure at least equal to ambient atmospheric pressure to maintain the person's airway at a positive pressure substantially continuously throughout said repeated breathing cycles;
passing such breathing gas through flow measuring means between such a source and the airway of such a person to continually monitor the flow;
responding to said flow measuring means to continually produce signals dependent on the instantaneous flow rate and the average flow rate of such breathing gas flowing between the source and the airway of the person;
passing said signals dependent on said instantaneous flow rate and said average flow rate to means capable of identifying the occurrence of said inspiratory and expiratory phases; and automatically adjusting the pressure of gas passing from said source to said person according to the said occurrence of each said inspiratory and expiratory phase to maintain said positive pressure in the person's airway substantially continuously during a sequence of said inspiratory and said expiratory phases with the magnitude of said positive pressure maintained during each said expiratory phase of said sequence being less than the magnitude of said positive pressure maintained during each immediately preceding inspiratory phase, respectively.
2. The method as set forth in claim 1 wherein said supplying step includes the supplying of breathing gas under pressure via a breathing appliance worn by such a person.
3. A method of providing breathing gas for breathing by a person comprising the steps of:
providing a flow of breathing gas from a source for delivery to the airway of such a person at selected higher and lower pressure magnitudes at least as great as ambient atmospheric pressure;
passing the breathing gas through flow measuring means which continually detect the instantaneous flow rate of said breathing gas flowing between said source and the airway of said person;
automatically and continually processing selected parameters including said instantaneous flow rate to provide a reference indicia corresponding to an average flow rate of breathing gas flowing between said source and said person; and passing signals dependent on said instantaneous flow rate and said reference indicia to comparator means for selecting one of said higher and said lower pressure magnitudes for said flow of breathing gas to be applied in the airway of such a person, dependent on whether the signals indicate an inspiratory or an expiratory phase.
providing a flow of breathing gas from a source for delivery to the airway of such a person at selected higher and lower pressure magnitudes at least as great as ambient atmospheric pressure;
passing the breathing gas through flow measuring means which continually detect the instantaneous flow rate of said breathing gas flowing between said source and the airway of said person;
automatically and continually processing selected parameters including said instantaneous flow rate to provide a reference indicia corresponding to an average flow rate of breathing gas flowing between said source and said person; and passing signals dependent on said instantaneous flow rate and said reference indicia to comparator means for selecting one of said higher and said lower pressure magnitudes for said flow of breathing gas to be applied in the airway of such a person, dependent on whether the signals indicate an inspiratory or an expiratory phase.
4. The method as set forth in claim 3 including the additional step of continually repeating said selecting step.
5. The method as set forth in claim 3 wherein said flow of breathing gas is a continuous flow of breathing gas.
6. The method as set forth in claim 3 wherein said comparator means is arranged to select said higher pressure magnitude when said instantaneous flow rate is greater than said reference indicia, and to select said lower pressure magnitude when said instantaneous flow rate is less than said reference indicia.
7. The method as set forth in claim 3 wherein said continually processing step includes adjusting a previously determined value of said reference indicia to provide an adjusted value thereof.
8. The method as set forth in claim 7 wherein said previously determined value of said reference indicia is included among said selected parameters.
9. The method as set forth in claim 8 wherein said continually processing step includes first processing of said instantaneous flow rate to provide a time average of the flow rate of breathing gas resulting from said providing step as a first component of said reference indicia.
10. The method as set forth in claim 9 wherein said continually processing step additionally includes second processing of said instantaneous flow rate and said reference indicia to provide a measure of the net flow of breathing gas to such a person for each spontaneous breath as a second component of said reference indicia.
11. The method as set forth in claim 10 wherein said continually processing step additionally includes third processing of said instantaneous flow rate and the occurrence of said selecting step to provide a measure of the instantaneous flow rate at the end of selected expiratory cycles as a third component of said reference indicia.
12. The method as set forth in claim 11 wherein said first, second and third processing steps are carried out simultaneously.
13. The method as set forth in claim 12 wherein said simultaneous first, second and third processing steps are carried out repetitively.
14. The method as set forth in claim 13 wherein said third processing step overrides said second processing step when said measure of the instantaneous flow rate at the end of said selected expiratory cycles differs from said reference indicia.
15. The method as set forth in claim 3 wherein said providing step includes providing said flow of breathing gas via a breathing gas delivery appliance worn by such a person.
16. An apparatus for delivering pressurized gas to the airway of a person who is breathing in repeated breathing cycles each including an inspiratory phase and an expiratory phase comprising:
a gas flow generator means for providing a flow of such gas;
means for delivery of such gas flow from said flow generator to the airway of such a person;
pressure controller means cooperable with said flow generator means to provide such gas flow within said means for delivery and within the airway of such a person at selectively variable pressures;
detector means for continually detecting the rate of flow of such gas between said flow generator means and the airway of such a person;
first processor means cooperable with said detector means to continually provide a first indicia corresponding to the instantaneous flow rate of such gas between said flow generator means and the airway of such a person;
second processor means cooperable with said first processor means to continually provide a reference indicia approximating the average positive flow rate of such gas between said flow generator means and the airway of such a person;
decision means operable to utilize said first indicia and said reference indicia to identify the occurrence of said inspiratory and expiratory phases; and said decision means being cooperable with said pressure controller means to control variation of the pressure of such gas flow in response to identification of the occurrence of said inspiratory and expiratory phases.
a gas flow generator means for providing a flow of such gas;
means for delivery of such gas flow from said flow generator to the airway of such a person;
pressure controller means cooperable with said flow generator means to provide such gas flow within said means for delivery and within the airway of such a person at selectively variable pressures;
detector means for continually detecting the rate of flow of such gas between said flow generator means and the airway of such a person;
first processor means cooperable with said detector means to continually provide a first indicia corresponding to the instantaneous flow rate of such gas between said flow generator means and the airway of such a person;
second processor means cooperable with said first processor means to continually provide a reference indicia approximating the average positive flow rate of such gas between said flow generator means and the airway of such a person;
decision means operable to utilize said first indicia and said reference indicia to identify the occurrence of said inspiratory and expiratory phases; and said decision means being cooperable with said pressure controller means to control variation of the pressure of such gas flow in response to identification of the occurrence of said inspiratory and expiratory phases.
17. The apparatus as set forth in claim 16 wherein said decision means is operable to adjust said pressure controller means to provide a higher pressure gas flow when said first indicia exceeds said reference indicia, and to provide a lower pressure gas flow when said first indicia is less than said reference indicia.
18. The apparatus as set forth in claim 17 wherein said second processor means includes processing elements operable to adjust an existing value of said reference indicia to provide an adjusted value thereof.
19. The apparatus as set forth in claim 18 wherein said processing elements include means for processing said first indicia to provide a time average of the flow rate of gas as a first component of said reference indicia.
20. The apparatus as set forth in claim 19 wherein said processing elements further include means for processing said first indicia and said reference indicia to provide a measure of such gas flow during a predeterminable time period as a second component of said reference indicia.
21. The apparatus as set forth in claim 20 wherein said predeterminable time period is a single complete breathing cycle of such a person including one inspiratory cycle and one expiratory cycle in sequence.
22. The apparatus as set forth in claim 21 wherein said processing elements further include means for processing said first indicia and to provide a measure of the value of said first indicia at the end of any such complete breathing cycle by such a person as a third component of said reference indicia.
23. A method of providing breathing gas for breathing by a person comprising the steps of:
providing breathing gas from a source for breathing by such a person;
supplying such breathing gas to the airway of such a person;
passing the flow of such breathing gas through flow measuring means between such a source and the airway of such a person to continually monitor the flow;
responding to said flow measuring means to continually produce signals dependent on the instantaneous flow rate and the average flow rate of such breathing gas flowing between the source and the airway of the person;
passing said signals dependent on said instantaneous flow rate and said average flow rate to means capable of identifying the occurrence of each inspiratory and expiratory phase of the person's respiration cycle; and automatically adjusting the pressure of gas passing from said source to said person according to said occurrence of each said inspiratory and expiratory phase to maintain positive pressure in the person's airway substantially continuously during a sequence of said inspiratory and said expiratory phases with the magnitude of said positive pressure maintained during each said expiratory phase of said sequence being less than the magnitude of said positive pressure maintained during each immediately preceding inspiratory phase, respectively.
providing breathing gas from a source for breathing by such a person;
supplying such breathing gas to the airway of such a person;
passing the flow of such breathing gas through flow measuring means between such a source and the airway of such a person to continually monitor the flow;
responding to said flow measuring means to continually produce signals dependent on the instantaneous flow rate and the average flow rate of such breathing gas flowing between the source and the airway of the person;
passing said signals dependent on said instantaneous flow rate and said average flow rate to means capable of identifying the occurrence of each inspiratory and expiratory phase of the person's respiration cycle; and automatically adjusting the pressure of gas passing from said source to said person according to said occurrence of each said inspiratory and expiratory phase to maintain positive pressure in the person's airway substantially continuously during a sequence of said inspiratory and said expiratory phases with the magnitude of said positive pressure maintained during each said expiratory phase of said sequence being less than the magnitude of said positive pressure maintained during each immediately preceding inspiratory phase, respectively.
24. A method of providing breathing gas for breathing by a person comprising the steps of:
providing a flow of breathing gas from a source for delivery to the airway of a person at selected higher and lower pressure magnitudes at least as great as ambient atmospheric pressure;
passing the breathing gas through flow measuring means which continually detect the instantaneous flow rate of said breathing gas flowing between said source and the airway of said person;
automatically and continually processing selected parameters including said instantaneous flow rate to provide a reference indicia corresponding to an average flow rate of breathing gas flowing between said source and said person; and passing signals dependent on said instantaneous flow rate and said reference indicia to comparator means for selecting one of said higher and said lower pressure magnitudes for said flow of breathing gas.
providing a flow of breathing gas from a source for delivery to the airway of a person at selected higher and lower pressure magnitudes at least as great as ambient atmospheric pressure;
passing the breathing gas through flow measuring means which continually detect the instantaneous flow rate of said breathing gas flowing between said source and the airway of said person;
automatically and continually processing selected parameters including said instantaneous flow rate to provide a reference indicia corresponding to an average flow rate of breathing gas flowing between said source and said person; and passing signals dependent on said instantaneous flow rate and said reference indicia to comparator means for selecting one of said higher and said lower pressure magnitudes for said flow of breathing gas.
25. In a system for providing breathing gas from a source for breathing by a person, a method of compensating for leakage of breathing gas from such a system comprising the steps of:
passing the breathing gas through flow measuring means which continually determine the instantaneous flow rate and the average flow rate of such breathing gas flowing between such a source and the airway of said person;
automatically and continually comparing said instantaneous flow rate and said average flow rate to determine the rate of gas leakage from the system; and passing signals responsive to said comparing step to means for adjusting the flow rate of breathing gas provided from said source to such a person to compensate for said rate of leakage.
passing the breathing gas through flow measuring means which continually determine the instantaneous flow rate and the average flow rate of such breathing gas flowing between such a source and the airway of said person;
automatically and continually comparing said instantaneous flow rate and said average flow rate to determine the rate of gas leakage from the system; and passing signals responsive to said comparing step to means for adjusting the flow rate of breathing gas provided from said source to such a person to compensate for said rate of leakage.
26. A method of providing breathing gas for breathing by a person comprising the steps of:
preventing episodes of airway obstruction by applying positive pressure greater than ambient atmospheric pressure within the airway of a person;
applying said positive pressure by supplying breathing gas at a positive pressure to the airway of said person;
automatically adjusting the pressure of gas in the person's airway to coordinate the person's airway pressure with the occurrence of alternating inspiratory and expiratory phases of the person's respiration in a manner to maintain said positive pressure in the person's airway substantially continuously during a sequence of said inspiratory and expiratory phases with the magnitude of said positive pressure maintained during each of said expiratory phases being less than the magnitude of said positive pressure maintained during the immediately preceding ones of said inspiratory phases, respectively;
and maintaining the magnitude of said positive pressure within the person's airway at a value sufficient to prevent said episodes of airway obstruction during said sequence of inspiratory and expiratory phases.
preventing episodes of airway obstruction by applying positive pressure greater than ambient atmospheric pressure within the airway of a person;
applying said positive pressure by supplying breathing gas at a positive pressure to the airway of said person;
automatically adjusting the pressure of gas in the person's airway to coordinate the person's airway pressure with the occurrence of alternating inspiratory and expiratory phases of the person's respiration in a manner to maintain said positive pressure in the person's airway substantially continuously during a sequence of said inspiratory and expiratory phases with the magnitude of said positive pressure maintained during each of said expiratory phases being less than the magnitude of said positive pressure maintained during the immediately preceding ones of said inspiratory phases, respectively;
and maintaining the magnitude of said positive pressure within the person's airway at a value sufficient to prevent said episodes of airway obstruction during said sequence of inspiratory and expiratory phases.
27. A method of providing gas from a source for breathing by a person who is breathing in repeated breathing cycles each including an inspiratory phase during which a flow of such gas passes from such a source to such a person and an expiratory phase during which a flow of such gas passes from such a person, said method comprising the steps of:
supplying such gas to the airway of such a person at a positive pressure at least equal to ambient atmospheric pressure to maintain the person's airway at such a positive pressure during said repeated breathing cycles;
passing at least one of said flows of gas through flow measuring means to monitor said flow;
responding to said flow measuring means to produce signals which allow determining of at least one of an instantaneous flow rate and an average flow rate of such gas;
utilizing said signals determining at least one of said instantaneous flow rate and said average flow rate by means capable of identifying the occurrence of said inspiratory and expiratory phases; and automatically adjusting the pressure of gas passing from said source to said person according to said occurrence of each said inspiratory and expiratory phase in a manner that said positive pressure is maintained in the person's airway during a sequence of said inspiratory and said expiratory phases with the magnitude of said positive pressure during selected ones of said expiratory phases in said sequence being less than the magnitude of said positive pressure during the respective immediately preceding inspiratory phases.
supplying such gas to the airway of such a person at a positive pressure at least equal to ambient atmospheric pressure to maintain the person's airway at such a positive pressure during said repeated breathing cycles;
passing at least one of said flows of gas through flow measuring means to monitor said flow;
responding to said flow measuring means to produce signals which allow determining of at least one of an instantaneous flow rate and an average flow rate of such gas;
utilizing said signals determining at least one of said instantaneous flow rate and said average flow rate by means capable of identifying the occurrence of said inspiratory and expiratory phases; and automatically adjusting the pressure of gas passing from said source to said person according to said occurrence of each said inspiratory and expiratory phase in a manner that said positive pressure is maintained in the person's airway during a sequence of said inspiratory and said expiratory phases with the magnitude of said positive pressure during selected ones of said expiratory phases in said sequence being less than the magnitude of said positive pressure during the respective immediately preceding inspiratory phases.
28. The method as set forth in claim 27 wherein said determining step includes determining at least one of said instantaneous and average flow rates of such gas flowing between such a source and the airway of such a person.
29. The method as set forth in claim 27 wherein said supplying step includes the supplying of breathing gas under pressure via a breathing appliance interfacing with such a person.
30. The method as set forth in claim 27 wherein said positive pressure is maintained in the person's airway substantially continuously during said sequence of said inspiratory and expiratory phases.
31. The method as set forth in claim 27 wherein said monitoring at least one of said flows of gas is continual monitoring thereof.
32. The method as set forth in claim 27 wherein said determining of at least one of an instantaneous flow rate and an average flow rate is continual determining thereof.
33. The method as set forth in claim 27 wherein said determining step includes determining both of said instantaneous flow rate and said average flow rate, and said utilizing step includes utilizing both of said instantaneous flow rate and said average flow rate.
34. The method as set forth in claim 27 wherein at least one of said magnitudes of said positive pressure is a substantially constant magnitude of positive pressure.
35. A method of providing breathing gas for breathing by a person comprising the steps of:
providing a flow of breathing gas from a source for delivery to the airway of such a person at selected higher and lower pressure magnitudes at least as great as ambient atmospheric pressure and permitting a flow of such breathing gas to pass from the person;
passing at least one of said flows through flow measuring means to monitor at least one of said flows and to detect an instantaneous flow rate of such breathing gas;
processing selected parameters including said instantaneous flow rate to provide a reference indicia corresponding to an average flow rate of such breathing gas; and automatically utilizing at least one of said instantaneous flow rate and said reference indicia to select one of said higher and said lower pressure magnitudes to be applied in the airway of such a person.
providing a flow of breathing gas from a source for delivery to the airway of such a person at selected higher and lower pressure magnitudes at least as great as ambient atmospheric pressure and permitting a flow of such breathing gas to pass from the person;
passing at least one of said flows through flow measuring means to monitor at least one of said flows and to detect an instantaneous flow rate of such breathing gas;
processing selected parameters including said instantaneous flow rate to provide a reference indicia corresponding to an average flow rate of such breathing gas; and automatically utilizing at least one of said instantaneous flow rate and said reference indicia to select one of said higher and said lower pressure magnitudes to be applied in the airway of such a person.
36. The method as set forth in claim 35 wherein said monitoring step includes monitoring at least one of said flows to detect an instantaneous flow rate of such breathing gas flowing between said source and the airway of such a person.
37. The method as set forth in claim 35 including the additional step of continually repeating said selecting step.
38. The method as set forth in claim 35 wherein said flow of breathing gas is a substantially continuous flow of breathing gas.
39. The method as set forth in claim 35 wherein said selecting step includes selecting said higher pressure magnitude when said instantaneous flow rate is greater than said reference indicia, and selecting said lower pressure magnitude when said instantaneous flow rate is less than said reference indicia.
40. The method as set forth in claim 35 wherein said processing step includes adjusting a previously determined value of said reference indicia to provide an adjusted value thereof.
41. The method as set forth in claim 40 wherein said previously determined value of said reference indicia is included among said selected parameters.
42. The method as set forth in claim 41 wherein said processing step includes first processing of said instantaneous flow rate to provide a time average of the flow rate of breathing gas resulting from said providing step as a first component of said reference indicia.
43. The method as set forth in claim 42 wherein said processing step additionally includes second processing of said instantaneous flow rate and said reference indicia to provide a measure of the net flow of breathing gas to such a person for each spontaneous breath as a second component of said reference indicia.
44. The method as set forth in claim 43 wherein said processing step additionally includes third processing of said instantaneous flow rate and the occurrence of said selecting step to provide a measure of said instantaneous flow rate at the end of selected expiratory cycles as a third component of said reference indicia.
45. The method as set forth in claim 44 wherein said first, second and third processing steps are carried out simultaneously.
46 46. The method as set forth in claim 45 wherein said simultaneous first, second and third processing steps are carried out repetitively.
47. The method as set forth in claim 46 wherein said third processing step overrides said second processing step when said measure of said instantaneous flow rate at the end of said selected expiratory cycles differs from said reference indicia.
48. The method as set forth in claim 35 wherein said providing step includes providing said flow of breathing gas via a breathing gas delivery appliance worn by such a person.
49. The method as set forth in claim 35 wherein said monitoring of at least one of said flows includes continual monitoring thereof.
50. The method as set forth in claim 35 wherein said processing of selected parameters includes continual processing thereof.
51. The method as set forth in claim 35 wherein said utilizing at least one of said instantaneous flow rate and said reference indicia includes utilizing both of said instantaneous flow rate and said reference indicia.
52. The method as set forth in claim 35 wherein at least one of said higher and lower pressure magnitudes is a substantially constant pressure magnitude.
53. An apparatus for delivering pressurized gas to the airway of a person who is breathing in repeated breathing cycles each including an inspiratory phase and an expiratory phase comprising:
a gas flow generator means for providing such gas;
supply means for delivery of a supply flow of such gas from said flow generator means to the airway of such a person;
exhaust means for allowing an exhaust flow of such gas to pass from the airway of such a person;
pressure controller means cooperable with said flow generator means to provide such supply flow within said supply means for delivery to the airway of such a person at selectively variable pressures;
monitoring means for monitoring the flow rate of at least one of said supply and exhaust flows;
processor means which is cooperable with said monitoring means to provide a first indicia corresponding to an instantaneous flow rate of such gas;
said processor means being further cooperable with said monitoring means to provide a reference indicia corresponding to an approximate average flow rate of such gas;
decision means operable to utilize at least one of said first indicia and said reference indicia to identify the occurrence of said inspiratory and expiratory phases; and said decision means being cooperable with said pressure controller means to control the pressure of such gas within said supply means for varying the pressure applied within the airway of such a person in response to identification of the occurrence of said inspiratory and expiratory phases.
a gas flow generator means for providing such gas;
supply means for delivery of a supply flow of such gas from said flow generator means to the airway of such a person;
exhaust means for allowing an exhaust flow of such gas to pass from the airway of such a person;
pressure controller means cooperable with said flow generator means to provide such supply flow within said supply means for delivery to the airway of such a person at selectively variable pressures;
monitoring means for monitoring the flow rate of at least one of said supply and exhaust flows;
processor means which is cooperable with said monitoring means to provide a first indicia corresponding to an instantaneous flow rate of such gas;
said processor means being further cooperable with said monitoring means to provide a reference indicia corresponding to an approximate average flow rate of such gas;
decision means operable to utilize at least one of said first indicia and said reference indicia to identify the occurrence of said inspiratory and expiratory phases; and said decision means being cooperable with said pressure controller means to control the pressure of such gas within said supply means for varying the pressure applied within the airway of such a person in response to identification of the occurrence of said inspiratory and expiratory phases.
54. The apparatus as set forth in claim 53 wherein said first indicia corresponds to an instantaneous flow rate of such gas in said supply means and said reference indicia corresponds to an approximate average flow rate of such gas in said supply means.
55. The apparatus as set forth in claim 53 wherein said decision means is operable to utilize both of said first indicia and said reference indicia, and is further operable to adjust said pressure controller means to provide a higher pressure within the airway of such a person when said first indicia exceeds said reference indicia, and to provide a lower pressure within the airway of such a person when said first indicia is less than said reference indicia.
56. The apparatus as set forth in claim 55 wherein said processor means includes processing elements operable to adjust an existing value of said reference indicia to provide an adjusted value thereof.
57. The apparatus as set forth in claim 56 wherein said processing elements include means for processing said first indicia to provide a time average of the flow rate of such gas within said supply means as a first component of said reference indicia.
58. The apparatus as set forth in claim 57 wherein said processing elements further include means for processing said first indicia and said reference indicia to provide a measure of the gas flow within said supply means during a predeterminable time period as a second component of said reference indicia.
59. The apparatus as set forth in claim 58 wherein said predeterminable time period is a single complete breathing cycle of such a person including one inspiratory cycle and one expiratory cycle in sequence.
60. The apparatus as set forth in claim 59 wherein said processing elements further include means for processing said first indicia to provide a measure of the value of said first indicia at the end of any such complete breathing cycle by such a person as a third component of said reference indicia.
61. The apparatus as set forth in claim 53 wherein said monitoring means is operable for continually monitoring the flow rate of at least one of said supply and exhaust flows.
62. The apparatus as set forth in claim 53 wherein said processor means includes first and second processor means, respectively, with one of said first and second processor means being cooperable with said monitoring means to provide said first indicia and the other of said first and second processor means being cooperable with said one of said processor means to provide said reference indicia.
63. The apparatus as set forth in claim 53 wherein said decision means is operable to utilize both of said first indicia and said reference indicia to identify the occurrence of said inspiratory and expiratory phases.
64. A method of providing breathing gas for breathing by a person comprising the steps of:
providing breathing gas from a source for breathing by a person;
supplying an inspiratory flow of such breathing gas to the airway of such a person;
permitting an expiratory flow of such breathing gas to pass from such a person;
passing at least one of said flows through flow measuring means to monitor the flow conditions of such breathing gas between such a source and the airway of such a person;
from said flow measuring means, producing signals indicative of at least one of an instantaneous flow rate and an average flow rate of such breathing gas;
passing said signals indicative of said at least one of said instantaneous flow rate and said average flow rate to means responsive to said signals to identify the occurrence of each inspiratory and expiratory phase of the person's respiration cycle;
and automatically adjusting the person's airway pressure with said occurrence of each said inspiratory and expiratory phase to maintain positive pressure in the person's airway during a sequence of said inspiratory and said expiratory phases with the magnitude of said positive pressure maintained during selected ones of said expiratory phases in said sequence being less than the magnitude of said positive pressure maintained during the respective immediately preceding inspiratory phases.
providing breathing gas from a source for breathing by a person;
supplying an inspiratory flow of such breathing gas to the airway of such a person;
permitting an expiratory flow of such breathing gas to pass from such a person;
passing at least one of said flows through flow measuring means to monitor the flow conditions of such breathing gas between such a source and the airway of such a person;
from said flow measuring means, producing signals indicative of at least one of an instantaneous flow rate and an average flow rate of such breathing gas;
passing said signals indicative of said at least one of said instantaneous flow rate and said average flow rate to means responsive to said signals to identify the occurrence of each inspiratory and expiratory phase of the person's respiration cycle;
and automatically adjusting the person's airway pressure with said occurrence of each said inspiratory and expiratory phase to maintain positive pressure in the person's airway during a sequence of said inspiratory and said expiratory phases with the magnitude of said positive pressure maintained during selected ones of said expiratory phases in said sequence being less than the magnitude of said positive pressure maintained during the respective immediately preceding inspiratory phases.
65. The method as set forth in claim 64 wherein said determining step includes determining said at least one of an instantaneous flow rate and an average flow rate of such breathing gas flowing between such a source and the airway of such a person.
66. The method as set forth in claim 64 wherein said determining step includes continually determining at least one of an instantaneous flow rate and an average flow rate of such breathing gas.
67. The method as set forth in claim 64 wherein said determining at least one of an instantaneous flow rate and an average flow rate includes determining both of said instantaneous flow rate and said average flow rate.
68. The method as set forth in claim 64 wherein the magnitude of said positive pressure maintained during at least one of said expiratory and said inspiratory phases is a constant magnitude of positive pressure.
69. The method as set forth in claim 64 wherein said positive pressure is maintained substantially continuously in the person's airway.
70. A method of providing breathing gas for breathing by a person comprising the steps of:
providing a supply flow of breathing gas from a source for delivery to the airway of a person at selected higher and lower pressure magnitudes at least as great as ambient atmospheric pressure;
permitting an exhaust flow of such breathing gas to pass from such a person;
passing at least one of said flows through flow measuring means to detect an instantaneous flow rate of said breathing gas;
automatically processing selected parameters including said instantaneous flow rate to provide a reference indicia corresponding to an average flow rate of said breathing gas; and passing signals dependent on at least one of said instantaneous flow rate and said reference indicia to comparator means for selecting one of said higher and said lower pressure magnitudes for said supply flow of breathing gas.
providing a supply flow of breathing gas from a source for delivery to the airway of a person at selected higher and lower pressure magnitudes at least as great as ambient atmospheric pressure;
permitting an exhaust flow of such breathing gas to pass from such a person;
passing at least one of said flows through flow measuring means to detect an instantaneous flow rate of said breathing gas;
automatically processing selected parameters including said instantaneous flow rate to provide a reference indicia corresponding to an average flow rate of said breathing gas; and passing signals dependent on at least one of said instantaneous flow rate and said reference indicia to comparator means for selecting one of said higher and said lower pressure magnitudes for said supply flow of breathing gas.
71. The method as set forth in claim 70 wherein said instantaneous flow rate and average flow rate of said breathing gas are, respectively, instantaneous and average flow rates of said breathing gas flowing between said source and the airway of such a person.
72. The method as set forth in claim 70 wherein said flow measuring means continually detect said flows.
73. The method as set forth in claim 70 wherein said processing selected parameters includes continual processing thereof.
74. The method as set forth in claim 70 wherein said comparator means utilizes both said instantaneous flow rate and said reference indicia to select one of said higher and said lower pressure magnitudes for said supply flow of breathing gas.
75. A method of providing breathing gas for breathing by a person comprising the steps of:
providing breathing gas from a source at positive pressure of a magnitude at least equal to ambient atmospheric pressure to the airway of a person; and automatically adjusting the pressure of gas passing from said source to said person according to said occurrence of alternating inspiratory and expiratory phases of the person's respiration to maintain said positive pressure in the person's airway during a sequence of said inspiratory and expiratory phases with the magnitude of said positive pressure during each said expiratory phase being less than the magnitude of said positive pressure during the immediately preceding inspiratory phase, respectively.
providing breathing gas from a source at positive pressure of a magnitude at least equal to ambient atmospheric pressure to the airway of a person; and automatically adjusting the pressure of gas passing from said source to said person according to said occurrence of alternating inspiratory and expiratory phases of the person's respiration to maintain said positive pressure in the person's airway during a sequence of said inspiratory and expiratory phases with the magnitude of said positive pressure during each said expiratory phase being less than the magnitude of said positive pressure during the immediately preceding inspiratory phase, respectively.
76. The method as set forth in claim 75 wherein said providing breathing gas at positive pressure includes substantially continuously providing.
77. The method as set forth in claim 75 wherein said step of automatically adjusting the pressure of gas passing from said source to said person according to said occurrence includes the step of substantially continuously maintaining said positive pressure.
78. The method as set forth in claim 75 wherein at least one of said magnitudes of positive pressure is a substantially constant magnitude of positive pressure.
79. In a system for directing a supply flow of breathing gas from a source for breathing by a person and for permitting an exhaust flow of gas to pass from such a person, a method of compensating for leakage of gas from such a system comprising the steps of:
passing at least one of said flows of gas through flow measuring means to monitor said flows;
from said flow measuring means, producing signals dependent on the instantaneous flow rate of the supply flow of breathing gas;
automatically processing selected parameters including said instantaneous flow rate to provide a reference indicia corresponding to an average flow rate of the supply flow of breathing gas;
passing signals dependent on said instantaneous flow rate and said reference indicia to comparator means for determining the magnitude of gas leakage from the system; and responding to said comparator means, automatically adjusting said supply flow of breathing gas to compensate for said gas leakage.
passing at least one of said flows of gas through flow measuring means to monitor said flows;
from said flow measuring means, producing signals dependent on the instantaneous flow rate of the supply flow of breathing gas;
automatically processing selected parameters including said instantaneous flow rate to provide a reference indicia corresponding to an average flow rate of the supply flow of breathing gas;
passing signals dependent on said instantaneous flow rate and said reference indicia to comparator means for determining the magnitude of gas leakage from the system; and responding to said comparator means, automatically adjusting said supply flow of breathing gas to compensate for said gas leakage.
80. The method as set forth in claim 79 wherein said monitoring step includes continual monitoring.
81. The method as set forth in claim 79 wherein said determining step includes continual determining.
82. The method as set forth in claim 79 wherein said comparator means continually compare said instantaneous flow rate and said reference indicia.
83. The method as set forth in claim 79 wherein said monitoring of at least one of said flows of gas includes monitoring both of said flows of gas.
84. The method as set forth in claim 79 wherein said processing step includes adjusting a previously determined value of said reference indicia to provide an adjusted value thereof.
85. The method as set forth in claim 84 wherein said previously determined value of said reference indicia is included among said selected parameters.
86. The method as set forth in claim 85 wherein said processing step includes first processing of said instantaneous flow rate to provide a time average of the flow rate of said supply flow of breathing gas as a first component of said reference indicia.
87. The method as set forth in claim 86 wherein said processing step additionally includes second processing of said instantaneous flow rate and said reference indicia to provide a measure of the net supply flow of breathing gas to such a person for each spontaneous breath as a second component of said reference indicia.
88. The method as set forth in claim 87 wherein said processing step additionally includes third processing of said instantaneous flow rate to provide periodic measurements of said instantaneous flow rate as a third component of said reference indicia.
89. The method as set forth in claim 88 wherein said first, second and third processing steps are carried out simultaneously.
90. The method as set forth in claim 89 wherein said simultaneous first, second and third processing steps are carried out repetitively.
91. The method as set forth in claim 90 wherein said third processing step overrides said second processing step when said measurement of said instantaneous flow rate differs from said reference indicia.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US411,012 | 1989-09-22 | ||
US07411012 US5148802B1 (en) | 1989-09-22 | 1989-09-22 | Method and apparatus for maintaining airway patency to treat sleep apnea and other disorders |
Publications (2)
Publication Number | Publication Date |
---|---|
CA2024477A1 CA2024477A1 (en) | 1991-03-23 |
CA2024477C true CA2024477C (en) | 1995-12-19 |
Family
ID=23627190
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA002024477A Expired - Lifetime CA2024477C (en) | 1989-09-22 | 1990-08-31 | Method and apparatus for providing breathing gas to a person, especially during treatment of sleep apnea |
Country Status (8)
Country | Link |
---|---|
US (3) | US5148802B1 (en) |
EP (1) | EP0425092B1 (en) |
JP (1) | JPH0716517B2 (en) |
AU (2) | AU695046B2 (en) |
CA (1) | CA2024477C (en) |
DE (2) | DE425092T1 (en) |
ES (1) | ES2034923T3 (en) |
FI (1) | FI105651B (en) |
Families Citing this family (380)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5199424A (en) * | 1987-06-26 | 1993-04-06 | Sullivan Colin E | Device for monitoring breathing during sleep and control of CPAP treatment that is patient controlled |
US5522382A (en) * | 1987-06-26 | 1996-06-04 | Rescare Limited | Device and method for treating obstructed breathing having a delay/ramp feature |
US5259373A (en) * | 1989-05-19 | 1993-11-09 | Puritan-Bennett Corporation | Inspiratory airway pressure system controlled by the detection and analysis of patient airway sounds |
US5239995A (en) * | 1989-09-22 | 1993-08-31 | Respironics, Inc. | Sleep apnea treatment apparatus |
US5632269A (en) * | 1989-09-22 | 1997-05-27 | Respironics Inc. | Breathing gas delivery method and apparatus |
US5148802B1 (en) * | 1989-09-22 | 1997-08-12 | Respironics Inc | Method and apparatus for maintaining airway patency to treat sleep apnea and other disorders |
US5101820A (en) * | 1989-11-02 | 1992-04-07 | Christopher Kent L | Apparatus for high continuous flow augmentation of ventilation and method therefor |
US5161525A (en) * | 1990-05-11 | 1992-11-10 | Puritan-Bennett Corporation | System and method for flow triggering of pressure supported ventilation |
EP0491969B1 (en) * | 1990-12-20 | 1995-08-23 | Siemens-Elema AB | Lung ventilator with a flow rate dependent trigger threshold |
US5265593A (en) * | 1991-05-02 | 1993-11-30 | Odland Rick M | Balloon-tipped catheter ventilation system and method for using same having rhythmically inflated and deflated balloon |
US5458137A (en) * | 1991-06-14 | 1995-10-17 | Respironics, Inc. | Method and apparatus for controlling sleep disorder breathing |
US6085747A (en) * | 1991-06-14 | 2000-07-11 | Respironics, Inc. | Method and apparatus for controlling sleep disorder breathing |
US6629527B1 (en) * | 1991-10-17 | 2003-10-07 | Respironics, Inc. | Sleep apnea treatment apparatus |
US5687715A (en) * | 1991-10-29 | 1997-11-18 | Airways Ltd Inc | Nasal positive airway pressure apparatus and method |
US5477852A (en) * | 1991-10-29 | 1995-12-26 | Airways Ltd., Inc. | Nasal positive airway pressure apparatus and method |
US7013892B2 (en) * | 1991-11-01 | 2006-03-21 | Ric Investments, Llc | Sleep apnea treatment apparatus |
ES2146591T3 (en) * | 1991-11-14 | 2000-08-16 | Univ Technologies Int | AUTOMATIC SYSTEM TO PROVIDE A CONTINUOUS POSITIVE PRESSURE IN THE NASAL RESPIRATORY TRACT. |
EP1149603A3 (en) | 1991-12-20 | 2003-10-22 | Resmed Limited | Ventilator for continuous positive airway pressure breathing (CPAP) |
US5385142A (en) * | 1992-04-17 | 1995-01-31 | Infrasonics, Inc. | Apnea-responsive ventilator system and method |
US5335654A (en) * | 1992-05-07 | 1994-08-09 | New York University | Method and apparatus for continuous adjustment of positive airway pressure for treating obstructive sleep apnea |
US5803066A (en) * | 1992-05-07 | 1998-09-08 | New York University | Method and apparatus for optimizing the continuous positive airway pressure for treating obstructive sleep apnea |
US5490502A (en) | 1992-05-07 | 1996-02-13 | New York University | Method and apparatus for optimizing the continuous positive airway pressure for treating obstructive sleep apnea |
CA2096302A1 (en) * | 1992-05-15 | 1993-11-16 | David Kilis | Air flow controller and recording system |
WO1993024169A1 (en) * | 1992-06-01 | 1993-12-09 | Cotner Ronald L | Demand positive pressure airway system for apnea treatment |
US5645054A (en) * | 1992-06-01 | 1997-07-08 | Sleepnet Corp. | Device and method for the treatment of sleep apnea syndrome |
US5343878A (en) * | 1992-06-08 | 1994-09-06 | Respironics Inc. | Pressure application method |
FR2692152B1 (en) * | 1992-06-15 | 1997-06-27 | Pierre Medical Sa | BREATHING AID, PARTICULARLY FOR TREATING SLEEP APNEA. |
FR2694697B1 (en) * | 1992-08-12 | 1994-10-14 | Sefam | Respiratory assistance device. |
FR2695320B1 (en) * | 1992-09-04 | 1994-12-09 | Sefam | Method for regulating the pressure of an air flow and respiratory assistance device implementing said method. |
FR2695830B1 (en) * | 1992-09-18 | 1994-12-30 | Pierre Medical Sa | Breathing aid device. |
US5353788A (en) * | 1992-09-21 | 1994-10-11 | Miles Laughton E | Cardio-respiratory control and monitoring system for determining CPAP pressure for apnea treatment |
US5517983A (en) * | 1992-12-09 | 1996-05-21 | Puritan Bennett Corporation | Compliance meter for respiratory therapy |
US5438980A (en) * | 1993-01-12 | 1995-08-08 | Puritan-Bennett Corporation | Inhalation/exhalation respiratory phase detection circuit |
US5685296A (en) * | 1993-07-30 | 1997-11-11 | Respironics Inc. | Flow regulating valve and method |
US5398676A (en) * | 1993-09-30 | 1995-03-21 | Press; Roman J. | Portable emergency respirator |
EP2113196A3 (en) | 1993-11-05 | 2009-12-23 | ResMed Limited | Control of CPAP treatment |
US6675797B1 (en) | 1993-11-05 | 2004-01-13 | Resmed Limited | Determination of patency of the airway |
DE4338813C1 (en) * | 1993-11-15 | 1995-02-23 | Metrax Gmbh | Respirator |
EP0661071B1 (en) | 1993-12-01 | 2000-02-02 | Resmed Limited | Device for continuous positive airway pressure breathing (CPAP) |
US5429123A (en) * | 1993-12-15 | 1995-07-04 | Temple University - Of The Commonwealth System Of Higher Education | Process control and apparatus for ventilation procedures with helium and oxygen mixtures |
US5542416A (en) * | 1994-01-12 | 1996-08-06 | Societe D'applications Industrielles Medicales Et Electroniques (Saime) | Apparatus for assisting ventilation including reduced exhalation pressure mode |
FR2714837B1 (en) * | 1994-01-12 | 1996-09-06 | Saime | Device for assisting the ventilation of a patient, comprising in particular a volumetric inspiratory assistance mode. |
US6932084B2 (en) * | 1994-06-03 | 2005-08-23 | Ric Investments, Inc. | Method and apparatus for providing positive airway pressure to a patient |
US5794615A (en) * | 1994-06-03 | 1998-08-18 | Respironics, Inc. | Method and apparatus for providing proportional positive airway pressure to treat congestive heart failure |
US5535738A (en) * | 1994-06-03 | 1996-07-16 | Respironics, Inc. | Method and apparatus for providing proportional positive airway pressure to treat sleep disordered breathing |
US6105575A (en) * | 1994-06-03 | 2000-08-22 | Respironics, Inc. | Method and apparatus for providing positive airway pressure to a patient |
AU683753B2 (en) * | 1994-07-06 | 1997-11-20 | Teijin Limited | An apparatus for assisting in ventilating the lungs of a patient |
SE503155C2 (en) * | 1994-07-28 | 1996-04-01 | Comasec International Sa | Methods and apparatus for functional control of breathing apparatus |
FI954092A (en) * | 1994-09-08 | 1996-03-09 | Weinmann G Geraete Med | Method of controlling a respirator in the treatment of sleep apnea |
DE4432219C1 (en) * | 1994-09-10 | 1996-04-11 | Draegerwerk Ag | Automatic breathing system for patients |
FR2724322A1 (en) * | 1994-09-12 | 1996-03-15 | Pierre Medical Sa | PRESSURE CONTROLLED BREATHING AID |
US6866040B1 (en) * | 1994-09-12 | 2005-03-15 | Nellcor Puritan Bennett France Developpement | Pressure-controlled breathing aid |
US5596984A (en) * | 1994-09-12 | 1997-01-28 | Puritan-Bennett Corporation | Lung ventilator safety circuit |
US5632270A (en) * | 1994-09-12 | 1997-05-27 | Puritan-Bennett Corporation | Method and apparatus for control of lung ventilator exhalation circuit |
EP1205206B1 (en) | 1994-10-14 | 2003-10-22 | Bird Products Corporation | Exhalation valve |
US5503146A (en) * | 1994-10-26 | 1996-04-02 | Devilbiss Health Care, Inc. | Standby control for CPAP apparatus |
US5551419A (en) * | 1994-12-15 | 1996-09-03 | Devilbiss Health Care, Inc. | Control for CPAP apparatus |
US5537997A (en) * | 1995-01-26 | 1996-07-23 | Respironics, Inc. | Sleep apnea treatment apparatus and passive humidifier for use therewith |
US5540219A (en) * | 1995-01-26 | 1996-07-30 | Respironics, Inc. | Sleep apnea treatment apparatus |
US5947115A (en) * | 1995-01-26 | 1999-09-07 | Respironics, Inc. | Gas flow pressure filter |
US5598838A (en) * | 1995-04-07 | 1997-02-04 | Healthdyne Technologies, Inc. | Pressure support ventilatory assist system |
AUPN236595A0 (en) | 1995-04-11 | 1995-05-11 | Rescare Limited | Monitoring of apneic arousals |
US5937855A (en) * | 1995-04-21 | 1999-08-17 | Respironics, Inc. | Flow regulating valve in a breathing gas delivery system |
US5598837A (en) * | 1995-06-06 | 1997-02-04 | Respironics, Inc. | Passive humidifier for positive airway pressure devices |
AUPN344195A0 (en) * | 1995-06-08 | 1995-07-06 | Rescare Limited | Monitoring of oro-nasal respiration |
AUPN394895A0 (en) * | 1995-07-03 | 1995-07-27 | Rescare Limited | Auto-calibration of pressure transducer offset |
AUPN474195A0 (en) * | 1995-08-09 | 1995-08-31 | Rescare Limited | Apparatus and methods for oro-nasal respiration monitoring |
US6000396A (en) * | 1995-08-17 | 1999-12-14 | University Of Florida | Hybrid microprocessor controlled ventilator unit |
AUPN547895A0 (en) | 1995-09-15 | 1995-10-12 | Rescare Limited | Flow estimation and compenstion of flow-induced pressure swings cpap treatment |
EP0862474A4 (en) | 1995-09-18 | 2000-05-03 | Resmed Ltd | Pressure control in cpap treatment or assisted respiration |
RU2072241C1 (en) * | 1995-09-20 | 1997-01-27 | Панина Елена Владимировна | Method and device for preparing inhalation gas mixture |
AUPN616795A0 (en) * | 1995-10-23 | 1995-11-16 | Rescare Limited | Ipap duration in bilevel cpap or assisted respiration treatment |
AUPN627395A0 (en) * | 1995-10-31 | 1995-11-23 | Compumedics Sleep Pty Ltd | Integrated diagnostic and therapeutic device for gas delivery to patient |
US5865173A (en) * | 1995-11-06 | 1999-02-02 | Sunrise Medical Hhg Inc. | Bilevel CPAP system with waveform control for both IPAP and EPAP |
US5682878A (en) * | 1995-12-07 | 1997-11-04 | Respironics, Inc. | Start-up ramp system for CPAP system with multiple ramp shape selection |
US6158432A (en) | 1995-12-08 | 2000-12-12 | Cardiopulmonary Corporation | Ventilator control system and method |
US6463930B2 (en) | 1995-12-08 | 2002-10-15 | James W. Biondi | System for automatically weaning a patient from a ventilator, and method thereof |
US5832916A (en) * | 1996-02-20 | 1998-11-10 | Interspiro Ab | Method and system for checking the operability of electrical-based components in a breathing equipment |
US5657752A (en) * | 1996-03-28 | 1997-08-19 | Airways Associates | Nasal positive airway pressure mask and method |
US5979456A (en) * | 1996-04-22 | 1999-11-09 | Magovern; George J. | Apparatus and method for reversibly reshaping a body part |
AUPN973596A0 (en) | 1996-05-08 | 1996-05-30 | Resmed Limited | Control of delivery pressure in cpap treatment or assisted respiration |
US6513526B2 (en) | 1996-07-26 | 2003-02-04 | Resmed Limited | Full-face mask and mask cushion therefor |
AUPO126596A0 (en) | 1996-07-26 | 1996-08-22 | Resmed Limited | A nasal mask and mask cushion therefor |
USD498529S1 (en) | 1996-07-26 | 2004-11-16 | Resmed Limited | Portion of a cushion for use with a mask assembly in the application of continuous positive airway pressure (CPAP) |
US5705735A (en) * | 1996-08-09 | 1998-01-06 | Medical Graphics Corporation | Breath by breath nutritional requirements analyzing system |
AUPO163896A0 (en) | 1996-08-14 | 1996-09-05 | Resmed Limited | Determination of respiratory airflow |
AU756622B2 (en) * | 1996-08-14 | 2003-01-16 | Resmed Limited | Determination of leak and respiratory airflow |
US5694923A (en) * | 1996-08-30 | 1997-12-09 | Respironics, Inc. | Pressure control in a blower-based ventilator |
US5701883A (en) * | 1996-09-03 | 1997-12-30 | Respironics, Inc. | Oxygen mixing in a blower-based ventilator |
AUPO247496A0 (en) | 1996-09-23 | 1996-10-17 | Resmed Limited | Assisted ventilation to match patient respiratory need |
AUPO301796A0 (en) * | 1996-10-16 | 1996-11-07 | Resmed Limited | A vent valve apparatus |
EP1015057B1 (en) * | 1996-12-12 | 2006-06-07 | The Johns Hopkins University School Of Medicine | Apparatus for providing ventilatory support to a patient |
AUPO418696A0 (en) | 1996-12-12 | 1997-01-16 | Resmed Limited | A substance delivery apparatus |
US5896857A (en) * | 1996-12-20 | 1999-04-27 | Resmed Limited | Valve for use in a gas delivery system |
AUPO425696A0 (en) | 1996-12-18 | 1997-01-23 | Resmed Limited | A device for preventing or reducing the passage of air through the mouth |
AUPO504597A0 (en) | 1997-02-10 | 1997-03-06 | Resmed Limited | A mask and a vent assembly therefor |
US6561191B1 (en) * | 1997-02-10 | 2003-05-13 | Resmed Limited | Mask and a vent assembly therefor |
AUPO511397A0 (en) | 1997-02-14 | 1997-04-11 | Resmed Limited | An apparatus for varying the flow area of a conduit |
US5881717A (en) * | 1997-03-14 | 1999-03-16 | Nellcor Puritan Bennett Incorporated | System and method for adjustable disconnection sensitivity for disconnection and occlusion detection in a patient ventilator |
KR100454157B1 (en) | 1997-05-07 | 2004-10-26 | 컴퓨메딕스 슬립 피티와이. 리미티드 | Apparatus for controlling gas delivery to patient |
JP2002514114A (en) | 1997-05-16 | 2002-05-14 | ピーター・クレイグ・ファーレル | Nostril respirator as a treatment for stroke |
AUPO742297A0 (en) | 1997-06-18 | 1997-07-10 | Resmed Limited | An apparatus for supplying breathable gas |
DE19738266A1 (en) * | 1997-09-02 | 1999-03-11 | Willi L Schaefer | Apnea mask for use in sleep |
US5954050A (en) * | 1997-10-20 | 1999-09-21 | Christopher; Kent L. | System for monitoring and treating sleep disorders using a transtracheal catheter |
AUPP015097A0 (en) | 1997-11-03 | 1997-11-27 | Resmed Limited | A mounting body |
AUPP026997A0 (en) | 1997-11-07 | 1997-12-04 | Resmed Limited | Administration of cpap treatment pressure in presence of apnea |
SE9704643D0 (en) * | 1997-12-12 | 1997-12-12 | Astra Ab | Inhalation apparatus and method |
US6192876B1 (en) * | 1997-12-12 | 2001-02-27 | Astra Aktiebolag | Inhalation apparatus and method |
US6017315A (en) | 1998-02-25 | 2000-01-25 | Respironics, Inc. | Patient monitor and method of using same |
US20050121033A1 (en) * | 1998-02-25 | 2005-06-09 | Ric Investments, Llc. | Respiratory monitoring during gas delivery |
CA2322193C (en) * | 1998-03-05 | 2006-10-24 | Batelle Memorial Institute | Pulmonary dosing system and method |
USD421298S (en) * | 1998-04-23 | 2000-02-29 | Resmed Limited | Flow generator |
AUPP366398A0 (en) | 1998-05-22 | 1998-06-18 | Resmed Limited | Ventilatory assistance for treatment of cardiac failure and cheyne-stokes breathing |
AUPP370198A0 (en) | 1998-05-25 | 1998-06-18 | Resmed Limited | Control of the administration of continuous positive airway pressure treatment |
US6564797B1 (en) * | 1998-09-30 | 2003-05-20 | Respironics, Inc. | Interactive pressure support system and method |
AUPP693398A0 (en) | 1998-11-05 | 1998-12-03 | Resmed Limited | Fault diagnosis in CPAP and NIPPV devices |
AUPP783198A0 (en) * | 1998-12-21 | 1999-01-21 | Resmed Limited | Determination of mask fitting pressure and correct mask fit |
EP1140263B1 (en) * | 1999-01-15 | 2011-05-11 | ResMed Limited | Method and apparatus to counterbalance intrinsic positive end expiratory pressure |
FR2789593B1 (en) * | 1999-05-21 | 2008-08-22 | Mallinckrodt Dev France | APPARATUS FOR SUPPLYING AIR PRESSURE TO A PATIENT WITH SLEEP DISORDERS AND METHODS OF CONTROLLING THE SAME |
US6467477B1 (en) | 1999-03-26 | 2002-10-22 | Respironics, Inc. | Breath-based control of a therapeutic treatment |
AUPP996499A0 (en) | 1999-04-23 | 1999-05-20 | Australian Centre For Advanced Medical Technology Ltd | A treatment for hypertension caused by pre-eclampsia |
US6135967A (en) | 1999-04-26 | 2000-10-24 | Fiorenza; Anthony Joseph | Respiratory ventilator with automatic flow calibration |
AUPQ019899A0 (en) * | 1999-05-06 | 1999-06-03 | Resmed Limited | Control of supplied pressure in assisted ventilation |
US6240919B1 (en) * | 1999-06-07 | 2001-06-05 | Macdonald John J. | Method for providing respiratory airway support pressure |
FR2794635B1 (en) | 1999-06-14 | 2001-08-03 | Taema | APPARATUS FOR DIAGNOSING OR TREATING SLEEP BREATHING DISORDERS AND METHOD OF OPERATION |
WO2000078379A1 (en) * | 1999-06-16 | 2000-12-28 | Resmed Ltd. | Apparatus with automatic respiration monitoring and display |
US6739335B1 (en) | 1999-09-08 | 2004-05-25 | New York University School Of Medicine | Method and apparatus for optimizing controlled positive airway pressure using the detection of cardiogenic oscillations |
DE60032929T2 (en) * | 1999-09-15 | 2007-10-25 | ResMed Ltd., Bella Vista | SYNCHRONIZING A VENTILATION DEVICE THROUGH DOUBLE PHASE SENSORS |
US6758216B1 (en) * | 1999-09-15 | 2004-07-06 | Resmed Limited | Ventilatory assistance using an external effort sensor |
US7225809B1 (en) * | 1999-11-01 | 2007-06-05 | Ric Investments, Llc | Method and apparatus for monitoring and controlling a medical device |
DE10014427A1 (en) * | 2000-03-24 | 2001-10-04 | Weinmann G Geraete Med | Method for controlling a ventilator and device for monitoring |
US6584977B1 (en) | 2000-04-06 | 2003-07-01 | Respironics, Inc. | Combined patient interface and exhaust assembly |
US6595212B1 (en) | 2000-04-17 | 2003-07-22 | Richard J. Arnott | Method and apparatus for maintaining airway patency |
US6581594B1 (en) * | 2000-05-15 | 2003-06-24 | Resmed Limited | Respiratory mask having gas washout vent and gas washout vent for respiratory mask |
DE10031079A1 (en) | 2000-06-30 | 2002-02-07 | Map Gmbh | Measuring patient breathing and state, correlates present respiration signals with prior reference measurements, to adjust CPAP therapy pressure accordingly |
US6532960B1 (en) | 2000-07-10 | 2003-03-18 | Respironics, Inc. | Automatic rise time adjustment for bi-level pressure support system |
US6814073B2 (en) | 2000-08-29 | 2004-11-09 | Resmed Limited | Respiratory apparatus with improved flow-flattening detection |
JP2002085568A (en) | 2000-09-21 | 2002-03-26 | Ngk Spark Plug Co Ltd | Oxygen supplier, controller and recording medium therefor |
JP4293581B2 (en) * | 2000-09-21 | 2009-07-08 | 日本特殊陶業株式会社 | Oxygen concentrator, control device, and recording medium |
CA2421808C (en) | 2000-09-28 | 2009-12-15 | Invacare Corporation | Carbon dioxide-based bi-level cpap control |
US6546930B1 (en) * | 2000-09-29 | 2003-04-15 | Mallinckrodt Inc. | Bi-level flow generator with manual standard leak adjustment |
US6644310B1 (en) * | 2000-09-29 | 2003-11-11 | Mallinckrodt Inc. | Apparatus and method for providing a breathing gas employing a bi-level flow generator with an AC synchronous motor |
US6622726B1 (en) * | 2000-10-17 | 2003-09-23 | Newport Medical Instruments, Inc. | Breathing apparatus and method |
DE10103810A1 (en) | 2001-01-29 | 2002-08-01 | Map Gmbh | Device for supplying a breathing gas |
US7066175B2 (en) * | 2001-05-07 | 2006-06-27 | Emergent Respiratory Products, Inc. | Portable gas powered positive pressure breathing apparatus and method |
US6851425B2 (en) | 2001-05-25 | 2005-02-08 | Respironics, Inc. | Exhaust port assembly for a pressure support system |
CA2351217C (en) * | 2001-06-19 | 2008-12-02 | Teijin Limited | An apparatus for supplying a therapeutic oxygen gas |
FR2826282B1 (en) | 2001-06-22 | 2004-05-28 | Taema | RESPIRATORY APPARATUS WITH STABILIZED PRESSURE TURBINE, TURBINE AND METHOD THEREOF |
SE0102400D0 (en) * | 2001-07-04 | 2001-07-04 | Siemens Elema Ab | Fluid flow regulation system |
US7938114B2 (en) * | 2001-10-12 | 2011-05-10 | Ric Investments Llc | Auto-titration bi-level pressure support system and method of using same |
US7168429B2 (en) * | 2001-10-12 | 2007-01-30 | Ric Investments, Llc | Auto-titration pressure support system and method of using same |
AU2002363780B2 (en) | 2001-11-16 | 2007-05-31 | Fisher & Paykel Healthcare Limited | A nasal positive pressure device |
US6892729B2 (en) | 2001-11-20 | 2005-05-17 | Fisher & Paykel Healthcare Limited | Patient interfaces |
AU2003225926B2 (en) | 2002-03-22 | 2006-09-28 | Invacare Corporation | Nasal mask |
US9155855B2 (en) | 2002-12-06 | 2015-10-13 | Fisher & Paykel Healthcare Limited | Mouthpiece |
US20040200472A1 (en) * | 2003-01-09 | 2004-10-14 | Suny Stony Brook/Respironics | Method of treating functional somatic syndromes and diagnosing sleep disorders based on functional somatic syndrome symptoms |
FR2850284B1 (en) * | 2003-01-27 | 2012-11-30 | Saime Sarl | BREATHING DEVICE AND REGULATION METHOD |
US7565906B2 (en) * | 2003-04-28 | 2009-07-28 | Ric Investments, Inc. | Pressure/flow control valve and system using same |
EP1477199A1 (en) * | 2003-05-15 | 2004-11-17 | Azienda Ospedaliera Pisana | Apparatus for non-invasive mechanical ventilation |
US7559326B2 (en) | 2003-06-18 | 2009-07-14 | Resmed Limited | Vent and/or diverter assembly for use in breathing apparatus |
US8020555B2 (en) * | 2003-06-18 | 2011-09-20 | New York University | System and method for improved treatment of sleeping disorders using therapeutic positive airway pressure |
DE10337138A1 (en) * | 2003-08-11 | 2005-03-17 | Freitag, Lutz, Dr. | Method and arrangement for the respiratory assistance of a patient as well as tracheal prosthesis and catheter |
US7588033B2 (en) | 2003-06-18 | 2009-09-15 | Breathe Technologies, Inc. | Methods, systems and devices for improving ventilation in a lung area |
AU2003903138A0 (en) * | 2003-06-20 | 2003-07-03 | Resmed Limited | Method and apparatus for improving the comfort of cpap |
US7152598B2 (en) | 2003-06-23 | 2006-12-26 | Invacare Corporation | System and method for providing a breathing gas |
US7621270B2 (en) | 2003-06-23 | 2009-11-24 | Invacare Corp. | System and method for providing a breathing gas |
US9789274B2 (en) * | 2003-07-09 | 2017-10-17 | Resmed R&D Germany Gmbh | Respiratory mask arrangement as well as headband arrangement and respiratory gas evacuation device for a respiratory mask |
US7114497B2 (en) * | 2003-07-18 | 2006-10-03 | Acoba, Llc | Method and system of individually controlling airway pressure of a patient's nares |
US7118536B2 (en) * | 2003-07-25 | 2006-10-10 | Ric Investments, Llc. | Apnea/hypopnea detection system and method |
US6988994B2 (en) * | 2003-08-14 | 2006-01-24 | New York University | Positive airway pressure system and method for treatment of sleeping disorder in patient |
EP1660004A4 (en) | 2003-08-18 | 2017-05-31 | Breathe Technologies, Inc. | Method and device for non-invasive ventilation with nasal interface |
US7044129B1 (en) * | 2003-09-03 | 2006-05-16 | Ric Investments, Llc. | Pressure support system and method |
US7343917B2 (en) * | 2003-09-22 | 2008-03-18 | Resmed Limited | Clear cycle for ventilation device |
US7041049B1 (en) * | 2003-11-21 | 2006-05-09 | First Principles, Inc. | Sleep guidance system and related methods |
US7866318B2 (en) * | 2004-01-07 | 2011-01-11 | Resmed Limited | Methods for providing expiratory pressure relief in positive airway pressure therapy |
US8011366B2 (en) * | 2004-02-04 | 2011-09-06 | Devilbiss Healthcare Llc | Method for acclimating a CPAP therapy patient to prescribed pressure |
US8783257B2 (en) | 2004-02-23 | 2014-07-22 | Fisher & Paykel Healthcare Limited | Breathing assistance apparatus |
EP1718356B1 (en) | 2004-02-25 | 2016-09-21 | Resmed Limited | Cardiac monitoring and therapy using a device for providing pressure treatment of sleep disordered breathing |
DE102004014538A1 (en) * | 2004-03-23 | 2005-10-13 | Seleon Gmbh | Method for controlling a BiLevel device and BiLevel device |
US9072852B2 (en) | 2004-04-02 | 2015-07-07 | Fisher & Paykel Healthcare Limited | Breathing assistance apparatus |
WO2005094928A1 (en) | 2004-04-02 | 2005-10-13 | Fisher & Paykel Healthcare Limited | Breathing assistance apparatus |
NZ550348A (en) | 2004-04-09 | 2011-02-25 | Resmed Ltd | Nasal assembly with vent and baffle |
WO2005099801A1 (en) | 2004-04-15 | 2005-10-27 | Resmed Limited | Positive-air-pressure machine conduit |
US7267121B2 (en) * | 2004-04-20 | 2007-09-11 | Aerogen, Inc. | Aerosol delivery apparatus and method for pressure-assisted breathing systems |
GB2413499A (en) * | 2004-04-28 | 2005-11-02 | Newcastle Upon Tyne Hospitals | Leak measurement around an uncuffed endo-tracheal tube |
US7276031B2 (en) * | 2004-05-12 | 2007-10-02 | New York University | System and method for classifying patient's breathing using artificial neural network |
US20050268912A1 (en) * | 2004-06-04 | 2005-12-08 | Norman Robert G | System and method for automated titration of continuous positive airway pressure |
US20060005834A1 (en) * | 2004-07-07 | 2006-01-12 | Acoba, Llc | Method and system of providing therapeutic gas to a patient to prevent breathing airway collapse |
US7882834B2 (en) * | 2004-08-06 | 2011-02-08 | Fisher & Paykel Healthcare Limited | Autotitrating method and apparatus |
US20060042627A1 (en) * | 2004-08-31 | 2006-03-02 | Macmillan Nicholas J | PAP titrate control method and apparatus |
US7717110B2 (en) | 2004-10-01 | 2010-05-18 | Ric Investments, Llc | Method and apparatus for treating Cheyne-Stokes respiration |
US20060096596A1 (en) * | 2004-11-05 | 2006-05-11 | Occhialini James M | Wearable system for positive airway pressure therapy |
US20060174885A1 (en) * | 2005-02-08 | 2006-08-10 | Acoba, Llc | Method and related system to control applied pressure in CPAP systems |
US7322356B2 (en) * | 2005-02-24 | 2008-01-29 | Restore Medical, Inc. | Combination sleep apnea treatment |
US7347205B2 (en) * | 2005-08-31 | 2008-03-25 | The General Electric Company | Method for use with the pressure triggering of medical ventilators |
EP1926517A2 (en) | 2005-09-20 | 2008-06-04 | Lutz Freitag | Systems, methods and apparatus for respiratory support of a patient |
US8025052B2 (en) * | 2005-11-21 | 2011-09-27 | Ric Investments, Llc | System and method of monitoring respiratory events |
WO2007062400A2 (en) * | 2005-11-23 | 2007-05-31 | Jianguo Sun | Method and apparatus for providing positive airway pressure to a patient |
NZ607280A (en) * | 2006-03-06 | 2014-06-27 | Resmed Ltd | Method and apparatus for improved flow limitation detection of obstructive sleep apnea |
DE102007011924A1 (en) * | 2006-03-08 | 2007-12-27 | Weinmann Geräte für Medizin GmbH & Co. KG | Method and device for controlling a ventilator |
JP4224610B2 (en) * | 2006-04-17 | 2009-02-18 | 興研株式会社 | Simulated breathing device for evaluation test of respiratory protective equipment |
CN101541365A (en) | 2006-05-18 | 2009-09-23 | 呼吸科技公司 | Tracheostoma tracheotomy method and device |
CA2890556C (en) | 2006-07-14 | 2018-05-01 | Fisher & Paykel Healthcare Limited | Breathing assistance apparatus |
JP2009544371A (en) | 2006-07-28 | 2009-12-17 | レスメド・リミテッド | Providing respiratory therapy |
NZ610755A (en) | 2006-07-28 | 2015-03-27 | Resmed Ltd | Delivery of respiratory therapy |
JP2009545384A (en) | 2006-08-03 | 2009-12-24 | ブリーズ テクノロジーズ, インコーポレイテッド | Method and apparatus for minimally invasive respiratory assistance |
US8069853B2 (en) * | 2006-08-14 | 2011-12-06 | Immediate Response Technologies | Breath responsive powered air-purifying respirator |
WO2008025080A1 (en) * | 2006-08-30 | 2008-03-06 | Resmed Ltd | Distinguishing closed and open respiratory airway apneas by complex admittance values |
US8322339B2 (en) * | 2006-09-01 | 2012-12-04 | Nellcor Puritan Bennett Llc | Method and system of detecting faults in a breathing assistance device |
US8316847B2 (en) * | 2006-09-01 | 2012-11-27 | Ventific Holdings Pty Ltd | Automatic positive airway pressure therapy through the nose or mouth for treatment of sleep apnea and other respiratory disorders |
US20080142013A1 (en) * | 2006-09-11 | 2008-06-19 | Michael David Hallett | Exhaust Apparatus For Use in Administering Positive Pressure Therapy Through the Nose or Mouth |
US20080060647A1 (en) * | 2006-09-12 | 2008-03-13 | Invacare Corporation | System and method for delivering a breathing gas |
CA2602005A1 (en) | 2006-09-18 | 2008-03-18 | Invacare Corporation | Breathing mask |
US20080078389A1 (en) * | 2006-09-29 | 2008-04-03 | Yang Xiao | Heliox delivery system and method with positive pressure support |
US20080078385A1 (en) * | 2006-09-29 | 2008-04-03 | Yang Xiao | System and method for delivery of medication via inhalation |
US8205615B1 (en) | 2006-09-29 | 2012-06-26 | Ric Investments, Llc | Self directing exhaust port assembly |
US20080114618A1 (en) | 2006-11-03 | 2008-05-15 | Kevin Pysnik | Patient information management system |
US20080114689A1 (en) * | 2006-11-03 | 2008-05-15 | Kevin Psynik | Patient information management method |
EP2101855B1 (en) | 2006-12-15 | 2013-08-21 | ResMed Limited | Respiratory Mask |
CH704346B1 (en) * | 2007-02-05 | 2012-07-13 | Imtmedical Ag | Control valve for ventilators. |
US8789527B2 (en) * | 2007-02-12 | 2014-07-29 | Ric Investments, Llc | Pressure support system with automatic comfort feature modification |
US7918226B2 (en) | 2007-04-10 | 2011-04-05 | General Electric Company | Method and system for detecting breathing tube occlusion |
US20080257348A1 (en) * | 2007-04-20 | 2008-10-23 | Piper S David | Emergency and mass casualty ventilator |
WO2008144589A1 (en) | 2007-05-18 | 2008-11-27 | Breathe Technologies, Inc. | Methods and devices for sensing respiration and providing ventilation therapy |
US8794235B2 (en) * | 2007-06-08 | 2014-08-05 | Ric Investments, Llc | System and method for treating ventilatory instability |
CA2696773A1 (en) | 2007-08-23 | 2009-02-26 | Invacare Corporation | Method and apparatus for adjusting desired pressure in positive airway pressure devices |
US20090078258A1 (en) * | 2007-09-21 | 2009-03-26 | Bowman Bruce R | Pressure regulation methods for positive pressure respiratory therapy |
US20090078255A1 (en) * | 2007-09-21 | 2009-03-26 | Bowman Bruce R | Methods for pressure regulation in positive pressure respiratory therapy |
CA2700878C (en) | 2007-09-26 | 2018-07-24 | Breathe Technologies, Inc. | Methods and devices for providing inspiratory and expiratory flow relief during ventilation therapy |
CN101888868B (en) | 2007-09-26 | 2014-01-22 | 呼吸科技公司 | Methods and devices for treating sleep apnea |
EP2220579B1 (en) * | 2007-12-04 | 2019-02-13 | Koninklijke Philips N.V. | Medical device |
US20090165795A1 (en) * | 2007-12-31 | 2009-07-02 | Nellcor Puritan Bennett Llc | Method and apparatus for respiratory therapy |
WO2009123981A1 (en) * | 2008-03-31 | 2009-10-08 | Nellcor Puritan Bennett Llc | Leak-compensated proportional assist ventilation |
US8267085B2 (en) | 2009-03-20 | 2012-09-18 | Nellcor Puritan Bennett Llc | Leak-compensated proportional assist ventilation |
US8272380B2 (en) | 2008-03-31 | 2012-09-25 | Nellcor Puritan Bennett, Llc | Leak-compensated pressure triggering in medical ventilators |
US8746248B2 (en) | 2008-03-31 | 2014-06-10 | Covidien Lp | Determination of patient circuit disconnect in leak-compensated ventilatory support |
WO2009123980A1 (en) | 2008-03-31 | 2009-10-08 | Nellcor Puritan Bennett Llc | System and method for determining ventilator leakage during stable periods within a breath |
EP2274036A4 (en) | 2008-04-18 | 2014-08-13 | Breathe Technologies Inc | Methods and devices for sensing respiration and controlling ventilator functions |
US8776793B2 (en) | 2008-04-18 | 2014-07-15 | Breathe Technologies, Inc. | Methods and devices for sensing respiration and controlling ventilator functions |
US8251876B2 (en) | 2008-04-22 | 2012-08-28 | Hill-Rom Services, Inc. | Breathing exercise apparatus |
US8752546B2 (en) | 2008-04-23 | 2014-06-17 | General Electric Company | System and method for mobilizing occlusions from a breathing tube |
AU2009245393B2 (en) * | 2008-05-07 | 2014-07-17 | Koninklijke Philips Electronics, N.V. | Exhaust assembly |
US10792451B2 (en) | 2008-05-12 | 2020-10-06 | Fisher & Paykel Healthcare Limited | Patient interface and aspects thereof |
US10258757B2 (en) | 2008-05-12 | 2019-04-16 | Fisher & Paykel Healthcare Limited | Patient interface and aspects thereof |
WO2009149355A1 (en) | 2008-06-06 | 2009-12-10 | Nellcor Puritan Bennett Llc | Systems and methods for monitoring and displaying respiratory information |
US11660413B2 (en) | 2008-07-18 | 2023-05-30 | Fisher & Paykel Healthcare Limited | Breathing assistance apparatus |
US8677999B2 (en) | 2008-08-22 | 2014-03-25 | Breathe Technologies, Inc. | Methods and devices for providing mechanical ventilation with an open airway interface |
EP2349420B1 (en) | 2008-09-25 | 2016-08-31 | Covidien LP | Inversion-based feed-forward compensation of inspiratory trigger dynamics in medical ventilators |
US8302602B2 (en) | 2008-09-30 | 2012-11-06 | Nellcor Puritan Bennett Llc | Breathing assistance system with multiple pressure sensors |
CA2739435A1 (en) | 2008-10-01 | 2010-04-08 | Breathe Technologies, Inc. | Ventilator with biofeedback monitoring and control for improving patient activity and health |
WO2010041966A1 (en) | 2008-10-10 | 2010-04-15 | Fisher & Paykel Healthcare Limited | Nasal pillows for a patient interface |
CN102186525B (en) * | 2008-10-17 | 2016-02-03 | 皇家飞利浦电子股份有限公司 | Fixing fabric structure in medical ventilator |
EP2334360B1 (en) | 2008-10-17 | 2016-12-14 | Koninklijke Philips N.V. | Inlet airflow assembly in a medical ventilator |
EP2445082B1 (en) | 2008-10-17 | 2014-07-02 | Koninklijke Philips N.V. | Medical ventilator comprising detachable battery pack |
CN102256649B (en) * | 2008-10-17 | 2014-12-17 | 皇家飞利浦电子股份有限公司 | Porting block for a medical ventilator |
JP5575789B2 (en) | 2008-11-19 | 2014-08-20 | インスパイア・メディカル・システムズ・インコーポレイテッド | How to treat sleep-disordered breathing |
AU2009325991B2 (en) * | 2008-12-09 | 2014-11-13 | Koninklijke Philips Electronics, N.V. | Automatic rise time adjustment |
WO2010070498A1 (en) | 2008-12-19 | 2010-06-24 | Koninklijke Philips Electronics, N.V. | System and method for treating lung disease using positive pressure airway support |
WO2010076712A1 (en) | 2008-12-30 | 2010-07-08 | Koninklijke Philips Electronics, N.V. | System and respiration appliance for supporting the airway of a subject |
WO2010076713A1 (en) | 2008-12-30 | 2010-07-08 | Koninklijke Philips Electronics, N.V. | System and respiration appliance for supporting the airway of a subject |
US9132250B2 (en) | 2009-09-03 | 2015-09-15 | Breathe Technologies, Inc. | Methods, systems and devices for non-invasive ventilation including a non-sealing ventilation interface with an entrainment port and/or pressure feature |
NZ612275A (en) * | 2009-02-11 | 2014-03-28 | Resmed Ltd | Acoustic detection for respiratory treatment apparatus |
US10137266B2 (en) * | 2009-02-25 | 2018-11-27 | Koninklijke Philips N.V. | Patient-ventilator dyssynchrony detection |
AU2010217313B2 (en) | 2009-02-25 | 2015-02-19 | Koninklijke Philips Electronics, N.V. | Pressure support system with machine delivered breaths |
US8424521B2 (en) | 2009-02-27 | 2013-04-23 | Covidien Lp | Leak-compensated respiratory mechanics estimation in medical ventilators |
US8418691B2 (en) | 2009-03-20 | 2013-04-16 | Covidien Lp | Leak-compensated pressure regulated volume control ventilation |
CA2757591C (en) | 2009-04-02 | 2021-01-05 | Breathe Technologies, Inc. | Methods, systems and devices for non-invasive open ventilation with gas delivery nozzles within an outer tube |
US9962512B2 (en) | 2009-04-02 | 2018-05-08 | Breathe Technologies, Inc. | Methods, systems and devices for non-invasive ventilation including a non-sealing ventilation interface with a free space nozzle feature |
US9392964B2 (en) | 2009-04-22 | 2016-07-19 | Resmed Limited | Detection of asynchrony |
US20100288283A1 (en) * | 2009-05-15 | 2010-11-18 | Nellcor Puritan Bennett Llc | Dynamic adjustment of tube compensation factor based on internal changes in breathing tube |
US8545231B2 (en) * | 2009-06-25 | 2013-10-01 | Charles Richard Lloyd | Obstructive sleep apnea demonstration model device |
CA2774902C (en) | 2009-09-03 | 2017-01-03 | Breathe Technologies, Inc. | Methods, systems and devices for non-invasive ventilation including a non-sealing ventilation interface with an entrainment port and/or pressure feature |
US8215302B2 (en) * | 2009-09-22 | 2012-07-10 | Kassatly L Samuel A | Discontinuous positive airway pressure device and method of reducing sleep disordered breathing events |
US8544468B2 (en) * | 2009-10-07 | 2013-10-01 | Richard J. Arnott | System, apparatus and method for maintaining airway patency and pressure support ventilation |
US10137271B2 (en) | 2009-11-18 | 2018-11-27 | Fisher & Paykel Healthcare Limited | Nasal interface |
GB2534305A (en) | 2009-12-23 | 2016-07-20 | Fisher & Paykel Healthcare Ltd | Patient interface and headgear |
US20120266884A1 (en) | 2009-12-28 | 2012-10-25 | Koninklijke Philips Electronics N.V. | Exhaust port assembly that minimizes noise |
BR112012017107A2 (en) | 2010-01-14 | 2017-10-17 | Koninl Philips Electronics Nv | systems for administering a breath gas flow to a patient's airway, method of ventilating a patient, and system for ventilating a patient |
EP2523715B1 (en) | 2010-01-14 | 2015-09-23 | Koninklijke Philips N.V. | Servo ventilation using negative pressure support |
AU2010343682B2 (en) | 2010-01-22 | 2015-01-29 | Koninklijke Philips Electronics N.V. | Automatically controlled ventilation system |
US8707952B2 (en) | 2010-02-10 | 2014-04-29 | Covidien Lp | Leak determination in a breathing assistance system |
WO2011107909A1 (en) | 2010-03-02 | 2011-09-09 | Koninklijke Philips Electronics N.V. | Helmet-type of patient interface device and method use |
AU2010201464B2 (en) * | 2010-04-14 | 2014-10-23 | Hallett, Michael | Automatic Positive Airway Pressure Therapy through the Nose or Mouth for Treatment of Sleep Apnea and Other Respiratory Disorders |
WO2011145014A1 (en) | 2010-05-17 | 2011-11-24 | Koninklijke Philips Electronics N.V. | System and method for estimating upper airway resistance and lung compliance employing induced central apneas |
CN107626026B (en) | 2010-06-04 | 2020-07-14 | 皇家飞利浦电子股份有限公司 | Automatic humidity control in a pressure support system |
JP5919263B2 (en) | 2010-06-04 | 2016-05-18 | コーニンクレッカ フィリップス エヌ ヴェKoninklijke Philips N.V. | Automatic temperature control in patient circuit |
CA2807416C (en) | 2010-08-16 | 2019-02-19 | Breathe Technologies, Inc. | Methods, systems and devices using lox to provide ventilatory support |
US20120060835A1 (en) * | 2010-09-13 | 2012-03-15 | General Electric Company | Anesthesia system and method |
WO2012045051A1 (en) | 2010-09-30 | 2012-04-05 | Breathe Technologies, Inc. | Methods, systems and devices for humidifying a respiratory tract |
US10569045B2 (en) | 2010-10-05 | 2020-02-25 | Richard J. Arnott | Apparatus and method for maintaining airway patency and pressure support ventilation |
US9561338B2 (en) | 2010-10-08 | 2017-02-07 | Fisher & Paykel Healthcare Limited | Breathing assistance apparatus |
US8844537B1 (en) | 2010-10-13 | 2014-09-30 | Michael T. Abramson | System and method for alleviating sleep apnea |
CN103260682B (en) | 2010-12-20 | 2016-03-16 | 皇家飞利浦电子股份有限公司 | Depend on the Respiration assistance of breathing rate |
US8991392B1 (en) | 2010-12-21 | 2015-03-31 | Fisher & Paykel Healthcare Limited | Pressure adjustment method for CPAP machine |
US8783250B2 (en) | 2011-02-27 | 2014-07-22 | Covidien Lp | Methods and systems for transitory ventilation support |
US9084859B2 (en) | 2011-03-14 | 2015-07-21 | Sleepnea Llc | Energy-harvesting respiratory method and device |
CN103561805A (en) * | 2011-03-30 | 2014-02-05 | 皇家飞利浦有限公司 | Methods to transition adjacent to or in conjunction with a secondary airway pressure therapy |
US8714154B2 (en) | 2011-03-30 | 2014-05-06 | Covidien Lp | Systems and methods for automatic adjustment of ventilator settings |
DE112012007300B4 (en) | 2011-04-15 | 2024-04-25 | Fisher & Paykel Healthcare Ltd. | Interface with a movable nose bridge |
US10603456B2 (en) | 2011-04-15 | 2020-03-31 | Fisher & Paykel Healthcare Limited | Interface comprising a nasal sealing portion |
US8776792B2 (en) | 2011-04-29 | 2014-07-15 | Covidien Lp | Methods and systems for volume-targeted minimum pressure-control ventilation |
JP6188682B2 (en) | 2011-05-20 | 2017-08-30 | コーニンクレッカ フィリップス エヌ ヴェKoninklijke Philips N.V. | Rotary electrical connector and breathing gas supply system using this connector |
JP6092212B2 (en) | 2011-08-11 | 2017-03-08 | インスパイア・メディカル・システムズ・インコーポレイテッドInspire Medical Systems, Inc. | System for selecting a stimulation protocol based on detection results of respiratory effort |
MX347550B (en) | 2011-09-21 | 2017-05-02 | Koninklijke Philips Nv | Upper airway resistance measurement device. |
US9364624B2 (en) | 2011-12-07 | 2016-06-14 | Covidien Lp | Methods and systems for adaptive base flow |
US9498589B2 (en) | 2011-12-31 | 2016-11-22 | Covidien Lp | Methods and systems for adaptive base flow and leak compensation |
US9022031B2 (en) | 2012-01-31 | 2015-05-05 | Covidien Lp | Using estimated carinal pressure for feedback control of carinal pressure during ventilation |
CN104379204A (en) | 2012-02-15 | 2015-02-25 | 费雪派克医疗保健有限公司 | System, apparatus and methods for supplying gases |
US9180271B2 (en) | 2012-03-05 | 2015-11-10 | Hill-Rom Services Pte. Ltd. | Respiratory therapy device having standard and oscillatory PEP with nebulizer |
WO2013148754A1 (en) * | 2012-03-28 | 2013-10-03 | Vapotherm, Inc. | Systems and methods for providing respiratory therapy with varying flow rates |
US9327089B2 (en) | 2012-03-30 | 2016-05-03 | Covidien Lp | Methods and systems for compensation of tubing related loss effects |
US8844526B2 (en) | 2012-03-30 | 2014-09-30 | Covidien Lp | Methods and systems for triggering with unknown base flow |
US9993604B2 (en) | 2012-04-27 | 2018-06-12 | Covidien Lp | Methods and systems for an optimized proportional assist ventilation |
AU2013263072B2 (en) * | 2012-05-14 | 2015-10-15 | Resmed Motor Technologies Inc. | Control of pressure for breathing comfort |
EP2859482A2 (en) | 2012-06-08 | 2015-04-15 | Koninklijke Philips N.V. | Patient sleep therapy self management tool |
US10362967B2 (en) | 2012-07-09 | 2019-07-30 | Covidien Lp | Systems and methods for missed breath detection and indication |
CN107626023B (en) | 2012-08-08 | 2021-03-02 | 费雪派克医疗保健有限公司 | Interface assembly for use in providing respiratory therapy |
EP2892596B1 (en) | 2012-09-04 | 2023-07-26 | Fisher&Paykel Healthcare Limited | Valsalva mask |
US9878123B2 (en) * | 2012-09-11 | 2018-01-30 | Fisher & Paykel Healthcare Limited | Surgical humidifier control |
US9375542B2 (en) | 2012-11-08 | 2016-06-28 | Covidien Lp | Systems and methods for monitoring, managing, and/or preventing fatigue during ventilation |
RU2015129063A (en) | 2012-12-20 | 2017-01-26 | Конинклейке Филипс Н.В. | AUTOMATIC PAIRING OF WIRELESS PERIPHERAL DEVICES WITH A SYSTEM SUCH AS A RESPIRATORY THERAPY SYSTEM WITH PRESSURE SUPPORT |
JP6792333B2 (en) * | 2012-12-26 | 2020-11-25 | コーニンクレッカ フィリップス エヌ ヴェKoninklijke Philips N.V. | Systems and methods for limiting flow and / or pressure compensation during limited flow respiratory therapy |
US9492629B2 (en) | 2013-02-14 | 2016-11-15 | Covidien Lp | Methods and systems for ventilation with unknown exhalation flow and exhalation pressure |
US9358355B2 (en) | 2013-03-11 | 2016-06-07 | Covidien Lp | Methods and systems for managing a patient move |
US9981096B2 (en) | 2013-03-13 | 2018-05-29 | Covidien Lp | Methods and systems for triggering with unknown inspiratory flow |
US10342942B2 (en) | 2013-03-15 | 2019-07-09 | Fisher & Paykel Healthcare Limited | Respiratory assistance device and method of controlling said device |
AU2014233838A1 (en) | 2013-03-21 | 2015-11-12 | Koninklijke Philips N.V. | A gas delivery system including a flow generator employing a continuously variable transmission |
US9610417B2 (en) | 2013-05-07 | 2017-04-04 | Gabrielle M Kassatly | Portable discontinuous positive airway pressure (DPAP) device and method of using the same |
US10493223B2 (en) * | 2013-06-19 | 2019-12-03 | Koninklijke Philips N.V. | Determining of subject zero flow using cluster analysis |
RU2677056C2 (en) | 2013-06-28 | 2019-01-15 | Конинклейке Филипс Н.В. | Humidifier assembly and method of providing moisture to supplied gas in a pressure support system |
JP6006903B2 (en) | 2013-08-12 | 2016-10-12 | コーニンクレッカ フィリップス エヌ ヴェKoninklijke Philips N.V. | Detection of fit of patient interface device |
US9675771B2 (en) | 2013-10-18 | 2017-06-13 | Covidien Lp | Methods and systems for leak estimation |
WO2015092695A1 (en) | 2013-12-18 | 2015-06-25 | Koninklijke Philips N.V. | Gas delivery system and method of sanitizing the gas flow path within a gas delivery system |
US9808591B2 (en) | 2014-08-15 | 2017-11-07 | Covidien Lp | Methods and systems for breath delivery synchronization |
GB2587307B (en) | 2014-08-25 | 2021-10-27 | Fisher & Paykel Healthcare Ltd | Respiratory mask and related portions, components or sub-assemblies |
TW202332392A (en) | 2014-09-16 | 2023-08-16 | 紐西蘭商費雪 & 佩凱爾關心健康有限公司 | Intramold headgear |
US10646680B2 (en) | 2014-09-19 | 2020-05-12 | Fisher & Paykel Healthcare Limited | Headgear assemblies and interface assemblies with headgear |
US9950129B2 (en) | 2014-10-27 | 2018-04-24 | Covidien Lp | Ventilation triggering using change-point detection |
US9925346B2 (en) | 2015-01-20 | 2018-03-27 | Covidien Lp | Systems and methods for ventilation with unknown exhalation flow |
US11497870B2 (en) | 2015-02-24 | 2022-11-15 | Somnetics International, Inc. | Systems and methods for estimating flow in positive airway pressure therapy |
CN113908438A (en) | 2015-03-19 | 2022-01-11 | 启迪医疗仪器公司 | Stimulation for treating sleep disordered breathing |
EP3277351B1 (en) | 2015-04-02 | 2019-06-05 | Hill-Rom Services PTE. LTD. | Manifold for respiratory device |
US20180133419A1 (en) | 2015-05-07 | 2018-05-17 | Koninklijke Philips N.V. | Monitoring the degradation of a component of a patient interface device |
US10792458B2 (en) | 2015-06-03 | 2020-10-06 | Koninklijke Philips N.V. | Rainout control in a pressure support system |
EP3313493B8 (en) | 2015-06-29 | 2020-04-01 | Koninklijke Philips N.V. | Collapsible humidifier |
EP3316949B1 (en) | 2015-06-30 | 2021-11-17 | Koninklijke Philips N.V. | Barometric pressure sensor for variable resistance positive airway pressure device circuit compensation |
US11298481B2 (en) | 2015-09-16 | 2022-04-12 | 12th Man Technologies, Inc. | Non-gas analyzer monitor of inspired gas concentration |
US10843015B2 (en) | 2015-10-22 | 2020-11-24 | Honeywell International Inc. | Smart respiratory face mask module |
US11298074B2 (en) | 2015-12-08 | 2022-04-12 | Fisher & Paykel Healthcare Limited | Flow-based sleep stage determination |
US20190001090A1 (en) | 2015-12-22 | 2019-01-03 | Koninklijke Philips N.V. | Pressure support device including sensor to detect non-sleep disordered breathing conditions |
AU2017234346B2 (en) | 2016-03-16 | 2022-06-30 | Fisher & Paykel Healthcare Limited | Directional lock for interface headgear arrangement |
CN115212416A (en) | 2016-03-16 | 2022-10-21 | 费雪派克医疗保健有限公司 | Bandage subassembly |
SG11201807697QA (en) | 2016-03-16 | 2018-10-30 | Fisher & Paykel Healthcare Ltd | Intra-mould substrate |
USD882066S1 (en) | 2016-05-13 | 2020-04-21 | Fisher & Paykel Healthcare Limited | Frame for a breathing mask |
JP7090618B2 (en) | 2016-12-23 | 2022-06-24 | コーニンクレッカ フィリップス エヌ ヴェ | Pressure assist devices and methods to identify changes in the patient circuit |
USD823454S1 (en) | 2017-02-23 | 2018-07-17 | Fisher & Paykel Healthcare Limited | Cushion assembly for breathing mask assembly |
USD824020S1 (en) | 2017-02-23 | 2018-07-24 | Fisher & Paykel Healthcare Limited | Cushion assembly for breathing mask assembly |
USD823455S1 (en) | 2017-02-23 | 2018-07-17 | Fisher & Paykel Healthcare Limited | Cushion assembly for breathing mask assembly |
US11458268B2 (en) | 2017-03-31 | 2022-10-04 | Koninklijke Philips N.V. | Systems and methods for concurrent airway stabilization and pulmonary stretch receptor activation |
US11298486B2 (en) | 2017-06-30 | 2022-04-12 | Koninklijke Philips N.V. | Systems and methods for concurrent airway stabilization and pulmonary stretch receptor activation |
JP7313341B2 (en) | 2017-09-28 | 2023-07-24 | コーニンクレッカ フィリップス エヌ ヴェ | Systems and methods for detecting stroke in patients during pressure support therapy |
WO2019063744A1 (en) | 2017-09-29 | 2019-04-04 | Koninklijke Philips N.V. | Pressure support device and method of providing an alert for non-effective pressure compensation regimen |
US10792449B2 (en) | 2017-10-03 | 2020-10-06 | Breathe Technologies, Inc. | Patient interface with integrated jet pump |
EP3525857B1 (en) | 2017-11-14 | 2020-01-29 | Covidien LP | Systems for drive pressure spontaneous ventilation |
US11116931B2 (en) | 2017-12-18 | 2021-09-14 | Koninklijke Philips N.V. | System and method for controlling conduit heating |
EP3727542A1 (en) | 2017-12-22 | 2020-10-28 | Koninklijke Philips N.V. | Improved delivery of a pressure support therapy |
AU2019235660A1 (en) | 2018-03-16 | 2020-09-24 | Fisher & Paykel Healthcare Limited | Headgear with lock disengagement mechanism |
EP3793656A1 (en) | 2018-05-14 | 2021-03-24 | Covidien LP | Systems and methods for respiratory effort detection utilizing signal distortion |
US11534568B2 (en) | 2018-06-28 | 2022-12-27 | Koninklijke Philips N.V. | Pressure support system and method of providing pressure support therapy to a patient |
US11517691B2 (en) | 2018-09-07 | 2022-12-06 | Covidien Lp | Methods and systems for high pressure controlled ventilation |
JP2022500101A (en) | 2018-09-21 | 2022-01-04 | コーニンクレッカ フィリップス エヌ ヴェKoninklijke Philips N.V. | Airway pressure support device powered by radio frequency |
US11752287B2 (en) | 2018-10-03 | 2023-09-12 | Covidien Lp | Systems and methods for automatic cycling or cycling detection |
WO2020136035A1 (en) | 2018-12-24 | 2020-07-02 | Koninklijke Philips N.V. | Pressure support system and method of providing pressure support therapy to a patient |
US11324954B2 (en) | 2019-06-28 | 2022-05-10 | Covidien Lp | Achieving smooth breathing by modified bilateral phrenic nerve pacing |
US11420007B2 (en) | 2020-08-05 | 2022-08-23 | Effortless Oxygen, Llc | Flow triggered gas delivery |
US11318276B2 (en) | 2020-08-05 | 2022-05-03 | Effortless Oxygen, Llc | Flow triggered gas delivery |
US11247008B1 (en) | 2020-08-05 | 2022-02-15 | Effortless Oxygen, Llc | Flow triggered gas delivery |
WO2022175487A1 (en) | 2021-02-22 | 2022-08-25 | Koninklijke Philips N.V. | Method for providing comfort feature in a pressure support device and pressure support device including same |
CN116916992A (en) | 2021-02-22 | 2023-10-20 | 皇家飞利浦有限公司 | Pressure support device |
CN112915330B (en) * | 2021-02-24 | 2023-02-14 | 浙江工业大学 | Mechanical ventilation platform pressure measurement compliance evaluation method |
Family Cites Families (65)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3191596A (en) * | 1960-09-19 | 1965-06-29 | Forrest M Bird | Respirator |
US3267935A (en) * | 1961-05-04 | 1966-08-23 | Air Shield Inc | Respiratory assister |
US3362404A (en) * | 1964-11-16 | 1968-01-09 | Bennett Respiration Products I | Respiration apparatus for administering intermittent positive pressure breathing therapy |
US3485243A (en) * | 1965-08-02 | 1969-12-23 | Bird F M | Respirator with improved exhalation valve and control means |
US3580051A (en) * | 1969-10-03 | 1971-05-25 | Us Army | Method for leak testing masks |
US3669108A (en) * | 1969-10-20 | 1972-06-13 | Veriflo Corp | Ventilator |
US3741208A (en) * | 1971-02-23 | 1973-06-26 | B Jonsson | Lung ventilator |
US4036221A (en) * | 1972-05-01 | 1977-07-19 | Sutter Hospitals Medical Research Foundation | Respirator |
US3972327A (en) * | 1973-03-22 | 1976-08-03 | Hoffmann-La Roche Inc. | Respirator |
US3896800A (en) * | 1973-07-27 | 1975-07-29 | Airco Inc | Method and apparatus for triggering the inspiratory phase of a respirator |
CH568756A5 (en) * | 1973-09-07 | 1975-11-14 | Hoffmann La Roche | |
US4031885A (en) * | 1975-10-15 | 1977-06-28 | Puritan-Bennett Corporation | Method and apparatus for determining patient lung pressure, compliance and resistance |
US4050458A (en) * | 1976-01-26 | 1977-09-27 | Puritan-Bennett Corporation | Respiration system with patient assist capability |
DE2651217B1 (en) * | 1976-11-10 | 1978-04-06 | Draegerwerk Ag, 2400 Luebeck | Test device for the tight fit of respiratory masks |
US4323064A (en) * | 1976-10-26 | 1982-04-06 | Puritan-Bennett Corporation | Volume ventilator |
US4207884A (en) * | 1976-12-20 | 1980-06-17 | Max Isaacson | Pressure controlled breathing apparatus |
US4082093A (en) * | 1977-04-27 | 1978-04-04 | Bourns, Inc. | Compensator valve |
GB1583273A (en) * | 1977-05-06 | 1981-01-21 | Medishield Corp Ltd | Lung ventilators |
SE418456B (en) * | 1979-06-21 | 1981-06-09 | Engstrom Medical Ab | ventilator |
SE434799B (en) * | 1980-06-18 | 1984-08-20 | Gambro Engstrom Ab | SET AND DEVICE FOR CONTROL OF A LUNG FAN |
US4457303A (en) * | 1980-11-26 | 1984-07-03 | Tritec Industries, Inc. | Respirating gas supply control method and apparatus therefor |
WO1982003326A1 (en) * | 1981-03-26 | 1982-10-14 | Kiszel Janos | Respirator device particularly for use in perinatal medicine |
US4592349A (en) * | 1981-08-10 | 1986-06-03 | Bird F M | Ventilator having an oscillatory inspiratory phase and method |
DE3119814C2 (en) * | 1981-05-19 | 1984-07-26 | Drägerwerk AG, 2400 Lübeck | HFJ ventilator with a controllable breathing gas source and device for generating negative pressure |
DE3206482C2 (en) * | 1982-02-23 | 1984-03-15 | Drägerwerk AG, 2400 Lübeck | Ventilation device with a device for safety monitoring |
FR2530148B1 (en) * | 1982-07-13 | 1985-11-29 | France Prod Oxygenes Co | DEVICE FOR THE TREATMENT OF PATIENT RESPIRATORY FAILURE |
US4550726A (en) * | 1982-07-15 | 1985-11-05 | Mcewen James A | Method and apparatus for detection of breathing gas interruptions |
US4461293A (en) * | 1982-12-03 | 1984-07-24 | Kircaldie, Randall, And Mcnab | Respirating gas supply method and apparatus therefor |
DE3401384A1 (en) * | 1984-01-17 | 1985-07-25 | Drägerwerk AG, 2400 Lübeck | DEVICE FOR THE SUPPLY OF VENTILATION GAS IN THE CLOSED BREATHING CIRCUIT OF A MEDICAL VENTILATOR |
US4655213A (en) * | 1983-10-06 | 1987-04-07 | New York University | Method and apparatus for the treatment of obstructive sleep apnea |
JPS6099268A (en) * | 1983-11-04 | 1985-06-03 | シャープ株式会社 | Constant flow control system |
DE3429345A1 (en) * | 1983-12-09 | 1985-06-13 | Drägerwerk AG, 2400 Lübeck | CIRCUIT BREATHING PROTECTOR FOR OVERPRESSURE OPERATION |
JPS60124940U (en) * | 1984-02-02 | 1985-08-23 | シャープ株式会社 | artificial respirator |
US4584996A (en) * | 1984-03-12 | 1986-04-29 | Blum Alvin S | Apparatus for conservative supplemental oxygen therapy |
US4612928A (en) * | 1984-08-28 | 1986-09-23 | Tiep Brian L | Method and apparatus for supplying a gas to a body |
US4527557A (en) * | 1984-11-01 | 1985-07-09 | Bear Medical Systems, Inc. | Medical ventilator system |
FR2573311B1 (en) * | 1984-11-20 | 1988-06-24 | Boc Sa Ohmeda | ARTIFICIAL VENTILATION APPARATUS HAVING A VOLUMETRIC INSPIRATORY ASSISTANCE DEVICE |
US4686975A (en) * | 1985-05-03 | 1987-08-18 | Applied Membrane Technology, Inc. | Electronic respirable gas delivery device |
JPS6294175A (en) * | 1985-10-18 | 1987-04-30 | 鳥取大学長 | Respiration synchronous type gas blowing apparatus and method |
US4846166A (en) * | 1985-11-12 | 1989-07-11 | University Of Cincinnati | Non-invasive quantitative method for fit testing respirators and corresponding respirator apparatus |
US4637385A (en) * | 1986-01-13 | 1987-01-20 | Tibor Rusz | Pulmonary ventilator controller |
US4773411A (en) * | 1986-05-08 | 1988-09-27 | Downs John B | Method and apparatus for ventilatory therapy |
US4674492A (en) * | 1986-07-25 | 1987-06-23 | Filcon Corporation | Alarm system for respirator apparatus and method of use |
US4765325A (en) * | 1986-12-12 | 1988-08-23 | Crutchfield Clifton D | Method and apparatus for determining respirator face mask fit |
IT1200044B (en) * | 1986-12-31 | 1989-01-05 | Elmed Ginevri Srl | CONSTANT FLOW PRESSURE BREATHER AND CONTROLLED VENTILATION |
GB8704104D0 (en) * | 1987-02-21 | 1987-03-25 | Manitoba University Of | Respiratory system load apparatus |
US5086768A (en) * | 1987-02-24 | 1992-02-11 | Filcon Corporation | Respiratory protective device |
US4765326A (en) * | 1987-04-20 | 1988-08-23 | Minnesota Mining And Manufacturing Company | Low-flow alarm system for powdered air-purifying respirator |
US4830008A (en) * | 1987-04-24 | 1989-05-16 | Meer Jeffrey A | Method and system for treatment of sleep apnea |
US4807616A (en) * | 1987-07-09 | 1989-02-28 | Carmeli Adahan | Portable ventilator apparatus |
US4823787A (en) * | 1987-07-09 | 1989-04-25 | Carmeli Adahan | Portable ventilator apparatus |
US4941469A (en) * | 1987-11-12 | 1990-07-17 | Carmeli Adahan | Portable ventilator apparatus |
US4782832A (en) * | 1987-07-30 | 1988-11-08 | Puritan-Bennett Corporation | Nasal puff with adjustable sealing means |
US4802485A (en) * | 1987-09-02 | 1989-02-07 | Sentel Technologies, Inc. | Sleep apnea monitor |
FR2623404A1 (en) * | 1987-11-19 | 1989-05-26 | Air Liquide | RESPIRATORY ASSISTANCE DEVICE |
FR2624744B1 (en) * | 1987-12-18 | 1993-09-17 | Inst Nat Sante Rech Med | METHOD FOR REGULATING AN ARTIFICIAL VENTILATION DEVICE AND SUCH A DEVICE |
US5065756A (en) * | 1987-12-22 | 1991-11-19 | New York University | Method and apparatus for the treatment of obstructive sleep apnea |
US4914957A (en) * | 1988-04-15 | 1990-04-10 | Westinghouse Electric Corp. | Leak test adaptor apparatus for facilitating leak testing face mask respirators |
US4823788A (en) * | 1988-04-18 | 1989-04-25 | Smith Richard F M | Demand oxygen controller and respiratory monitor |
US4957107A (en) * | 1988-05-10 | 1990-09-18 | Sipin Anatole J | Gas delivery means |
US5134995A (en) * | 1989-05-19 | 1992-08-04 | Puritan-Bennett Corporation | Inspiratory airway pressure system with admittance determining apparatus and method |
US5107831A (en) * | 1989-06-19 | 1992-04-28 | Bear Medical Systems, Inc. | Ventilator control system using sensed inspiratory flow rate |
US5148802B1 (en) * | 1989-09-22 | 1997-08-12 | Respironics Inc | Method and apparatus for maintaining airway patency to treat sleep apnea and other disorders |
US5161525A (en) * | 1990-05-11 | 1992-11-10 | Puritan-Bennett Corporation | System and method for flow triggering of pressure supported ventilation |
US5117819A (en) * | 1990-09-10 | 1992-06-02 | Healthdyne, Inc. | Nasal positive pressure device |
-
1989
- 1989-09-22 US US07411012 patent/US5148802B1/en not_active Expired - Lifetime
-
1990
- 1990-08-31 CA CA002024477A patent/CA2024477C/en not_active Expired - Lifetime
- 1990-09-17 FI FI904566A patent/FI105651B/en not_active IP Right Cessation
- 1990-09-21 EP EP90310357A patent/EP0425092B1/en not_active Expired - Lifetime
- 1990-09-21 DE DE199090310357T patent/DE425092T1/en active Pending
- 1990-09-21 ES ES90310357T patent/ES2034923T3/en not_active Expired - Lifetime
- 1990-09-21 DE DE69021681T patent/DE69021681T2/en not_active Expired - Lifetime
- 1990-09-25 JP JP2252032A patent/JPH0716517B2/en not_active Expired - Fee Related
-
1992
- 1992-06-19 US US07/901,506 patent/US5313937A/en not_active Expired - Lifetime
- 1992-09-18 US US07/947,156 patent/US5433193A/en not_active Expired - Lifetime
-
1995
- 1995-09-08 AU AU30679/95A patent/AU695046B2/en not_active Withdrawn - After Issue
- 1995-09-11 AU AU30678/95A patent/AU3067895A/en not_active Abandoned
Also Published As
Publication number | Publication date |
---|---|
AU3067995A (en) | 1995-11-16 |
US5148802B1 (en) | 1997-08-12 |
ES2034923T1 (en) | 1993-04-16 |
DE69021681T2 (en) | 1996-02-15 |
AU3850893A (en) | 1993-07-29 |
AU661575B2 (en) | 1995-07-27 |
AU695046B2 (en) | 1998-08-06 |
EP0425092A1 (en) | 1991-05-02 |
JPH03222963A (en) | 1991-10-01 |
AU3067895A (en) | 1995-11-16 |
AU638054B2 (en) | 1993-06-17 |
CA2024477A1 (en) | 1991-03-23 |
EP0425092B1 (en) | 1995-08-16 |
US5433193A (en) | 1995-07-18 |
US5313937A (en) | 1994-05-24 |
FI105651B (en) | 2000-09-29 |
FI904566A0 (en) | 1990-09-17 |
DE69021681D1 (en) | 1995-09-21 |
DE425092T1 (en) | 1993-02-25 |
JPH0716517B2 (en) | 1995-03-01 |
US5148802A (en) | 1992-09-22 |
AU6222190A (en) | 1991-03-28 |
ES2034923T3 (en) | 1995-10-01 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CA2024477C (en) | Method and apparatus for providing breathing gas to a person, especially during treatment of sleep apnea | |
USRE35295E (en) | Sleep apnea treatment apparatus | |
US5239995A (en) | Sleep apnea treatment apparatus | |
US6305374B1 (en) | Breathing gas delivery method and apparatus | |
US5535738A (en) | Method and apparatus for providing proportional positive airway pressure to treat sleep disordered breathing | |
US5794615A (en) | Method and apparatus for providing proportional positive airway pressure to treat congestive heart failure | |
AU2004203313B2 (en) | Method and apparatus for providing breathing gas to a patient | |
AU734319B2 (en) | Method and apparatus for providing breathing gas to a patient | |
AU766227B2 (en) | Method and apparatus for providing breathing gas to a patient | |
AU723681B2 (en) | Method for treatment of sleep apnea | |
CA2259795C (en) | Method of determining leak component of gas flow | |
AU2008200756A1 (en) | Method and apparatus for providing breathing gas to a patient | |
AU2004203432B2 (en) | Method and apparatus for providing positive airway pressure to a patient | |
AU733655B2 (en) | Breathing gas delivery method |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
EEER | Examination request | ||
MKEX | Expiry |