CA1108039A - System for measurement of oxygen uptake and respiratory quotient - Google Patents
System for measurement of oxygen uptake and respiratory quotientInfo
- Publication number
- CA1108039A CA1108039A CA324,064A CA324064A CA1108039A CA 1108039 A CA1108039 A CA 1108039A CA 324064 A CA324064 A CA 324064A CA 1108039 A CA1108039 A CA 1108039A
- Authority
- CA
- Canada
- Prior art keywords
- flow
- flow resistance
- pneumotachograph
- gases
- resistance means
- 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
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/05—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects
- G01F1/34—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by measuring pressure or differential pressure
- G01F1/36—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by measuring pressure or differential pressure the pressure or differential pressure being created by the use of flow constriction
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/08—Detecting, measuring or recording devices for evaluating the respiratory organs
- A61B5/087—Measuring breath flow
- A61B5/0876—Measuring breath flow using means deflected by the fluid stream, e.g. flaps
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/05—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects
- G01F1/34—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by measuring pressure or differential pressure
- G01F1/36—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by measuring pressure or differential pressure the pressure or differential pressure being created by the use of flow constriction
- G01F1/40—Details of construction of the flow constriction devices
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
- G01N33/483—Physical analysis of biological material
- G01N33/497—Physical analysis of biological material of gaseous biological material, e.g. breath
Landscapes
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Molecular Biology (AREA)
- Biomedical Technology (AREA)
- General Health & Medical Sciences (AREA)
- Fluid Mechanics (AREA)
- Chemical & Material Sciences (AREA)
- Pathology (AREA)
- Biophysics (AREA)
- Physiology (AREA)
- Heart & Thoracic Surgery (AREA)
- Pulmonology (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Surgery (AREA)
- Medical Informatics (AREA)
- Hematology (AREA)
- Urology & Nephrology (AREA)
- Animal Behavior & Ethology (AREA)
- Food Science & Technology (AREA)
- Medicinal Chemistry (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- Immunology (AREA)
- Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
- Investigating Or Analysing Biological Materials (AREA)
- Sampling And Sample Adjustment (AREA)
Abstract
Abstract A system for measuring the oxygen uptake and respiratory quotient of a patient which employs a high resistance gas flow path in parallel with a pneumotachograph. The high resistance path is connected to each side of the diaphragm of the pneumotachograph and a small chamber is included in the high resistance path at each end thereof adjacent its connection to the pneumotachograph. The volume of the high resistance path, together with its resistance relative to that of the pneumotachograph is chosen such that, during respiration of the patient employing the device, the high resistance tube will never be completely flushed through in one direction before flow starts in the opposite direction. The high resistance line is chosen to be a constant resistance such that the amount of flow therethrough is proportional to the flow through the pneumotachograph. Thus by sampling and analyzing a small portion of the the two chamber and measuring the amount of gas flow by the pneumotachograph, the exact amount of oxygen uptake can be calculated.
Description
The direct measurement of oxygen uptake and respiratory quotient is often of importance in medical research or medical care. Many methods are available to make this measurement, but most of them suffer from serious defects. To make the measurement directly from the airway, it is necessary to know the respiratory minute volume, and also the exact concentration of mean inspired gas and mean expired gas for oxygen and carbon dioxide. The measurement of this mean volume and of the two gas concentrations usually requires bulky spirometers and other large apparatus, or else depends upon lligh flow past the nose and mouth, with downstream sampling. Alternately, La ~ha gas concentrations can be measured continuously during inspiration andexplration with the measured concentrations multiplied by the amount of Elow and then integrated to obtain the necessary values; but this requires a gas analyzer of extremely rapid response and very careful control of all Elows in the system. Because of the careful control required such systems have not proved very accurate.
The invention is incorporated in a pneumotachograph to which has been added a sampling tube on each side of its resistance means. Each tube is connected to a small chamber and the chambers are interconnected by means of a relatively high constant resistance path having a sufficient volume to prevent complete flushing thereof in one direction before flow starts in another direction by reason of the patient's breathing.
The invention provides apparatus for use in a system for measuring oxygen uptake and the like comprising first conduit means for conducting flow of respiration gases to and from a patient, said first conduit means includ-ing first flow resistance means~ second conduit means having one end thereof in communication with said first conduit means on one side of said first flow resistance means and the other end thereof in communication with said first conduit means on the other side of said first flow resistance means, said second conduit means including second flow resistance means, the volume of said second conduit means being substantially greater than the volume of gases conducted therethrough by a single breath of the patient whereby flush-ing of the second conduit means is preclwded, and sampling means coupled .~
3~
adjacent the ends of said second conduit means for analyzing the gases therein.
Such apparatus permits very accurate such measurements with rela-tively inexpensive gas analyzers and at the same time without the need of bulky or large apparatus to encumber the patient.
FIGURE 1 is a schematic diagram of apparatus for measuring oxygen -uptake and respiratory quotient in accordance with the invention wherein the high resistance path incorporates a series of small diameter tubes arranged in parallel;
1~ FIGURE 2 is a schematic diagram of another apparatus for measuring oxygen uptake and respiratory quotient in accordance with the invention but wherein the high resistance path is provided by the use of an additional pneumotachograph.
Referring to FIGURE l there is shown a pneumotachograph or sensing head ll. Generally, a pneumotachograph is an instrument for measuring flow by measuring the differential pressure across a resistance in the line of flow. The resistance is constant over a wide range of flow so that the pressure can be read directly as a simple function of the differential pressure. The constant resistance may be created by multiple parallel tubes sufficiently small to maintain the flow laminar. Alternatively, the resistance may be created by a moving orifice or other device, keeping in mind that the resistance is to be constant over the range of flow.
The pneumotachograph 11 shown in FIGURE 1 is substantially as shown in applican~'s United States Patent 4,083~245 entitled "Variable Orifice Gas Flow Sensing Head". As set forth in that application, the sensing head 11 is disposed in a gas flow line 13 through which gas may flow hori~ontally in the direction of the arrows 15. The head may include inlet and outlet por-tions 17 and 18 having ports 19 and 20 each of which carries a flange 21, 23 for securing them together. An orifice membrane 25 is retained ketween the flanges 21, 23 by means of screws 27 and the like. Flap 31 is joined inte-grally with the membrane 25 and hinged at 33.
Pressure ports 35 and 37 are provided in the sensing head 11 and ~ ....
t are connected to a differential pressure gauge 39 by means of the tubes 41 and 43 so as to permit reading of the gas flow. The apex 45 of the orifice in membrane 25 is disposed at the bottom thereof for easy passage of fluids which may be carried in the line.
I~hile the pneumotachograph 11 set forth above is as described in United States 4,083,245 and is the preferred type o pneumotachograph to be utilized in this invention, it is not entirely necessary that this particular type pneumotachograph be employed. Other constant resistance devices may be substituted.
-2a-' '' '' '' "
In addition to the elemerlts set forth above, there are two additional tubes 1~7 and 49 connected to the pneumotachograph 11 on opposite sides of the membrane 25 at openings 51 and 53 which are disposed in the upper region of the pneumo-tachograph so as to avoid interference with free fluids which may be carried 5 through the pneumotachograph.
Each of the tubes 47 and 49 connect with a small chamber 55,57 each of which carries a series of baffles 59. The chamber 57 will be employed ~o sample inspiration gases and the chamber 55 to sample expiration gases.
The opposite ends of the chambers 55 and 57 are connected to ~he opposite ends lû of a series of small parallel tubes 61. Tubes 61 are chosen in size to collectively have a rather high resistance compared to that of the pneumotachograph 11 and to individually be of sufficiently small internal diameter (e.g. 3 mm.) that theflow through it is laminar. In some instances it is satisfactory to employ a single long loop of tubing rather than the multiple tubes.
15 During the course of actual respiration flow passes alternately in each direction through the pneumotachograph 11 and likewise flows through the chambers 553 57 and the tubes 61 alternately back and forth at a fraction of the rate through the pneumotachograph 11. By proper selection of the size of the tubes 61 and the chambers 55, 57 together with the assistance of the baffles 59 to retard mixing 20 in the chambers, the chamber 55 will always contain a sample which is an average of the gas which is passed from left to right through the pneumotachograph 11. The chamber 57 will always contain a sample which is an average oI the gas which is passed from right to left through the pneumo-tachograph 11.
25 By means of taps 63 and 65 the gases in the chambers 55 and 57 may be sampledand their composition determined. The composition of the gas in the chambers 55 and 57 is an average of the expiration and inspiration gases and sampling cantherefore be done at a relatively slow rate, the gas composition not changing rapidly over several breaths.
30 It should be recogni~ed that the resistance o~ the pneumotachograph 11 is con-stant over a large range of flow and rnay be designated Rl. The resistance of the tubes 61 is also constant over a wi~ range since their small internal diameter causes a laminar flow. This resistance may be designated R2. The number~ size 3~
and length of the tubes 61 are chosen such that R2 is much greater than Rl and it has been found convenient to make R2 fifty to one hundred times greater than Rl. Flow through the pneumotachograph 11 and tubes 61 are inversely proportional to their respec~ive resistances. Thus, if R2 is one hundred ~imes 5 greater than Rl, the flow through the pneumotachograph 11 will be exactly 100 times the flow through the loop 61 and the total flow will be 1.01 times the flow through the pneumotachograph or one hundred and one times the flow through the tubes 61.
With the above factors known for any specific embodiment of the invention~ it 10 can be seen that calculation of oxygen uptake is an easy matter. The total flow of gases can be calculated by known means from the reading of the differential pressure gauge 39. The quantitative composition of both expired and inspired gases can be determined by connecting the taps 63 and 65 to a gas analyzer ~as shown with respect to another emhodimen~ in FIGURE 2) and multiplying the 15 readings thereof by a multiplier based upon $he relative resistance of the pneumotachograph 11 and tubes 61.
The actual sizes, volumes and so forth OI the chambers 55 and 57 and tubes loop 61 may vary considerably with the expected respiratory rate and volume~ P~s an example, it may be assumed that a particular patient expires about one liter per20 breath. If the resistance of ~he tubes 61 is one hundred times the resistance of the pneumotachograph 11, about 10 ml. will flow through the tubes 61 during each expiration. If the tubes 61 have a total volume of abou~ 50 ml. it will be seen that the expired gases will move through the tubes 61 only about one-fifth of their length before expiration is comple~e and the direction of flow reversesdue to inspiration. Thus, gases from the chambers 55 and 57 never intermix.
The exact shape of the chambers or the configuration of the tubes 61, or even ofthe pneumotachograph are not Important to the invention. In fact the resistance of the tubes 61 can be supplied by other means, including a pneumotachograph like element of very high resistance such as set forth in FIGURE 2.
30 In the embodiment shown in FIGUR~ 2 elements identical to those of the embodiment shown in FIGURE 1 are identified with like reference numerals and are not further described.
In the embodiment of FIGURE 2 the high resistance ean be provided by an element 67, similar to a pneumotachograph but without lines to a pressure gauge - ~-since flo~v rate therethrough need not be measured. The resistance element 67 isconnected to the tubes 47949 through relatively elongated chambers 69 and 71 each of which carries baffles 73. The baffles 73 serve the same purpose as the baffles 59 in the embodiment shown in FIGURE 1 and the resistance element 67 5 serves the same purpose as ~he tubes 61. The size of the resistance element 67 is considerably smaller than that of the pneumotachograph 11 whereby its resistance is considerably greater than that of the larger ur~. Again, the path from the opening 51 through the chamber 69, resistance element 67 and chamber 71 to the opening 53 has sufficient volume and includes sufficient baffles 73 that 10 they are never completely flushed during a single breath. A slug of gas moves back and forth through the pneumotachograph 67 with boundary interfaces somewhere within the chambers 69 and 71 but essentially never mixing in any large way with the ~ases in those chambers.
To actually calculate the oxygen uptake samples are taken from the chambers 69 15 and 71through the taps 75 and 77, respectively, leading to a gas analyzer 79 through a valve 81. It need only be necessary ~o assure that the volumes drawn for sampling are sufficiently small that there is no appreciable effect on the concentration of the gases in the chambers 69 and 71.
The apparatus of the invention replaces the Oouglas Bags and spirometers of 20 early methods and can be made very small and portable. Even so the device of the invention gives valid samples for measurements which are very reliable and do not require the use of rapid gas analyzers. The invention provides a method for making measurements which greatly reduces the bulk of the bags or tubing required and the gas analyzers need have a response time of only about 15 or 20 25 seconds. Moreover, the devices are simpler, lighter and less susceptible to difficulty from saliva contamination and leaks than are the devices of the priorart~
The invention is incorporated in a pneumotachograph to which has been added a sampling tube on each side of its resistance means. Each tube is connected to a small chamber and the chambers are interconnected by means of a relatively high constant resistance path having a sufficient volume to prevent complete flushing thereof in one direction before flow starts in another direction by reason of the patient's breathing.
The invention provides apparatus for use in a system for measuring oxygen uptake and the like comprising first conduit means for conducting flow of respiration gases to and from a patient, said first conduit means includ-ing first flow resistance means~ second conduit means having one end thereof in communication with said first conduit means on one side of said first flow resistance means and the other end thereof in communication with said first conduit means on the other side of said first flow resistance means, said second conduit means including second flow resistance means, the volume of said second conduit means being substantially greater than the volume of gases conducted therethrough by a single breath of the patient whereby flush-ing of the second conduit means is preclwded, and sampling means coupled .~
3~
adjacent the ends of said second conduit means for analyzing the gases therein.
Such apparatus permits very accurate such measurements with rela-tively inexpensive gas analyzers and at the same time without the need of bulky or large apparatus to encumber the patient.
FIGURE 1 is a schematic diagram of apparatus for measuring oxygen -uptake and respiratory quotient in accordance with the invention wherein the high resistance path incorporates a series of small diameter tubes arranged in parallel;
1~ FIGURE 2 is a schematic diagram of another apparatus for measuring oxygen uptake and respiratory quotient in accordance with the invention but wherein the high resistance path is provided by the use of an additional pneumotachograph.
Referring to FIGURE l there is shown a pneumotachograph or sensing head ll. Generally, a pneumotachograph is an instrument for measuring flow by measuring the differential pressure across a resistance in the line of flow. The resistance is constant over a wide range of flow so that the pressure can be read directly as a simple function of the differential pressure. The constant resistance may be created by multiple parallel tubes sufficiently small to maintain the flow laminar. Alternatively, the resistance may be created by a moving orifice or other device, keeping in mind that the resistance is to be constant over the range of flow.
The pneumotachograph 11 shown in FIGURE 1 is substantially as shown in applican~'s United States Patent 4,083~245 entitled "Variable Orifice Gas Flow Sensing Head". As set forth in that application, the sensing head 11 is disposed in a gas flow line 13 through which gas may flow hori~ontally in the direction of the arrows 15. The head may include inlet and outlet por-tions 17 and 18 having ports 19 and 20 each of which carries a flange 21, 23 for securing them together. An orifice membrane 25 is retained ketween the flanges 21, 23 by means of screws 27 and the like. Flap 31 is joined inte-grally with the membrane 25 and hinged at 33.
Pressure ports 35 and 37 are provided in the sensing head 11 and ~ ....
t are connected to a differential pressure gauge 39 by means of the tubes 41 and 43 so as to permit reading of the gas flow. The apex 45 of the orifice in membrane 25 is disposed at the bottom thereof for easy passage of fluids which may be carried in the line.
I~hile the pneumotachograph 11 set forth above is as described in United States 4,083,245 and is the preferred type o pneumotachograph to be utilized in this invention, it is not entirely necessary that this particular type pneumotachograph be employed. Other constant resistance devices may be substituted.
-2a-' '' '' '' "
In addition to the elemerlts set forth above, there are two additional tubes 1~7 and 49 connected to the pneumotachograph 11 on opposite sides of the membrane 25 at openings 51 and 53 which are disposed in the upper region of the pneumo-tachograph so as to avoid interference with free fluids which may be carried 5 through the pneumotachograph.
Each of the tubes 47 and 49 connect with a small chamber 55,57 each of which carries a series of baffles 59. The chamber 57 will be employed ~o sample inspiration gases and the chamber 55 to sample expiration gases.
The opposite ends of the chambers 55 and 57 are connected to ~he opposite ends lû of a series of small parallel tubes 61. Tubes 61 are chosen in size to collectively have a rather high resistance compared to that of the pneumotachograph 11 and to individually be of sufficiently small internal diameter (e.g. 3 mm.) that theflow through it is laminar. In some instances it is satisfactory to employ a single long loop of tubing rather than the multiple tubes.
15 During the course of actual respiration flow passes alternately in each direction through the pneumotachograph 11 and likewise flows through the chambers 553 57 and the tubes 61 alternately back and forth at a fraction of the rate through the pneumotachograph 11. By proper selection of the size of the tubes 61 and the chambers 55, 57 together with the assistance of the baffles 59 to retard mixing 20 in the chambers, the chamber 55 will always contain a sample which is an average of the gas which is passed from left to right through the pneumotachograph 11. The chamber 57 will always contain a sample which is an average oI the gas which is passed from right to left through the pneumo-tachograph 11.
25 By means of taps 63 and 65 the gases in the chambers 55 and 57 may be sampledand their composition determined. The composition of the gas in the chambers 55 and 57 is an average of the expiration and inspiration gases and sampling cantherefore be done at a relatively slow rate, the gas composition not changing rapidly over several breaths.
30 It should be recogni~ed that the resistance o~ the pneumotachograph 11 is con-stant over a large range of flow and rnay be designated Rl. The resistance of the tubes 61 is also constant over a wi~ range since their small internal diameter causes a laminar flow. This resistance may be designated R2. The number~ size 3~
and length of the tubes 61 are chosen such that R2 is much greater than Rl and it has been found convenient to make R2 fifty to one hundred times greater than Rl. Flow through the pneumotachograph 11 and tubes 61 are inversely proportional to their respec~ive resistances. Thus, if R2 is one hundred ~imes 5 greater than Rl, the flow through the pneumotachograph 11 will be exactly 100 times the flow through the loop 61 and the total flow will be 1.01 times the flow through the pneumotachograph or one hundred and one times the flow through the tubes 61.
With the above factors known for any specific embodiment of the invention~ it 10 can be seen that calculation of oxygen uptake is an easy matter. The total flow of gases can be calculated by known means from the reading of the differential pressure gauge 39. The quantitative composition of both expired and inspired gases can be determined by connecting the taps 63 and 65 to a gas analyzer ~as shown with respect to another emhodimen~ in FIGURE 2) and multiplying the 15 readings thereof by a multiplier based upon $he relative resistance of the pneumotachograph 11 and tubes 61.
The actual sizes, volumes and so forth OI the chambers 55 and 57 and tubes loop 61 may vary considerably with the expected respiratory rate and volume~ P~s an example, it may be assumed that a particular patient expires about one liter per20 breath. If the resistance of ~he tubes 61 is one hundred times the resistance of the pneumotachograph 11, about 10 ml. will flow through the tubes 61 during each expiration. If the tubes 61 have a total volume of abou~ 50 ml. it will be seen that the expired gases will move through the tubes 61 only about one-fifth of their length before expiration is comple~e and the direction of flow reversesdue to inspiration. Thus, gases from the chambers 55 and 57 never intermix.
The exact shape of the chambers or the configuration of the tubes 61, or even ofthe pneumotachograph are not Important to the invention. In fact the resistance of the tubes 61 can be supplied by other means, including a pneumotachograph like element of very high resistance such as set forth in FIGURE 2.
30 In the embodiment shown in FIGUR~ 2 elements identical to those of the embodiment shown in FIGURE 1 are identified with like reference numerals and are not further described.
In the embodiment of FIGURE 2 the high resistance ean be provided by an element 67, similar to a pneumotachograph but without lines to a pressure gauge - ~-since flo~v rate therethrough need not be measured. The resistance element 67 isconnected to the tubes 47949 through relatively elongated chambers 69 and 71 each of which carries baffles 73. The baffles 73 serve the same purpose as the baffles 59 in the embodiment shown in FIGURE 1 and the resistance element 67 5 serves the same purpose as ~he tubes 61. The size of the resistance element 67 is considerably smaller than that of the pneumotachograph 11 whereby its resistance is considerably greater than that of the larger ur~. Again, the path from the opening 51 through the chamber 69, resistance element 67 and chamber 71 to the opening 53 has sufficient volume and includes sufficient baffles 73 that 10 they are never completely flushed during a single breath. A slug of gas moves back and forth through the pneumotachograph 67 with boundary interfaces somewhere within the chambers 69 and 71 but essentially never mixing in any large way with the ~ases in those chambers.
To actually calculate the oxygen uptake samples are taken from the chambers 69 15 and 71through the taps 75 and 77, respectively, leading to a gas analyzer 79 through a valve 81. It need only be necessary ~o assure that the volumes drawn for sampling are sufficiently small that there is no appreciable effect on the concentration of the gases in the chambers 69 and 71.
The apparatus of the invention replaces the Oouglas Bags and spirometers of 20 early methods and can be made very small and portable. Even so the device of the invention gives valid samples for measurements which are very reliable and do not require the use of rapid gas analyzers. The invention provides a method for making measurements which greatly reduces the bulk of the bags or tubing required and the gas analyzers need have a response time of only about 15 or 20 25 seconds. Moreover, the devices are simpler, lighter and less susceptible to difficulty from saliva contamination and leaks than are the devices of the priorart~
Claims (11)
1. Apparatus for use in a system for measuring oxygen uptake and the like comprising first conduit means for conducting flow of respiration gases to and from a patient, said first conduit means including first flow resistance means, second conduit means having one end thereof in communication with said first conduit means on one side of said first flow resistance means and the other end thereof in communication with said first conduit means on the other side of saidfirst flow resistance means, said second conduit means including second flow resistance means, the volume of said second conduit means being substantially greater than the volume of gases conducted therethrough by a single breath of the patient whereby flushing of the second conduit means is precluded, and sampling means coupled adjacent the ends of said second conduit means for analyzing the gases therein.
2. Apparatus as defined in Claim 1 wherein said second flow resistance means affords substantially greater resistance to the flow of gases than said first flow resistance means.
3. Apparatus as defined in Claim 1 wherein said first flow resistance means comprises a pneumotachograph.
4. Apparatus as defined in Claim 1 wherein said second flow resistance means comprises an elongated tube.
5. Apparatus as defined in Claim 1 wherein said second flow resistance means comprises a series of elongated tubes arranged in parallel.
6. Apparatus as defined in Claim 1 wherein said second flow resistance means comprises a housing having inlet and outlet ports and an orifice membrane disposed across the interior of said housing between said inlet and outlet ports, said orifice membrane being formed of an elastic material, said orifice membrane including a partially cut-out portion defining an orifice and a flap integral with and hingably connected to the membrane and substantially coextensive with the orifice,said flap including sides which converge to form the narrowest portion of the flap at that portion thereof most remote from the hinged connection to the orifice membrane, said hinged connection being narrower than the widest portion of said flap.
7. Apparatus as defined in Claim 1 wherein said first and second flow resistancemeans each provide a constant resistance to the flow of respiration gases over awide range of flow velocity.
8. Apparatus as defined in Claim 1 wherein said second flow resistance means affords resistance to the flow of gases fifty times greater than does said firstflow resistance means.
9. Apparatus as defined in Claim 1 wherein said second flow resistance means affords resistance to the flow of gases one hundred times greater than does saidfirst flow resistance means.
10. Apparatus as defined in Claim 1 wherein said second conduit means comprises a first chamber at one end thereof and a second chamber at the other end thereof, said second flow resistance means being disposed in communication between said chambers, said sampling means being coupled to said chambers.
11. Apparatus as defined in Claim 10 together with baffle means disposed within said first and second chambers.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/894,189 US4197857A (en) | 1978-04-06 | 1978-04-06 | System for measurement of oxygen uptake and respiratory quotient |
| US894,189 | 1986-08-07 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1108039A true CA1108039A (en) | 1981-09-01 |
Family
ID=25402733
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA324,064A Expired CA1108039A (en) | 1978-04-06 | 1979-03-23 | System for measurement of oxygen uptake and respiratory quotient |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US4197857A (en) |
| JP (1) | JPS54135489A (en) |
| BE (1) | BE875336A (en) |
| CA (1) | CA1108039A (en) |
| DE (1) | DE2913208A1 (en) |
| FR (1) | FR2421593A1 (en) |
| GB (1) | GB2018426B (en) |
Families Citing this family (55)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2457675A1 (en) * | 1979-05-29 | 1980-12-26 | Research Dev Corp | PITOT TUBE PNEUMOTACHOGRAPHER |
| US4368740A (en) * | 1980-11-03 | 1983-01-18 | Binder Andy S | Physiologic analyzer |
| FI72645C (en) * | 1986-03-19 | 1987-07-10 | Instrumentarium Oy | STRIPMODUL FOER GASSTROEMNING. |
| US4993269A (en) * | 1988-12-16 | 1991-02-19 | Bird Products Corporation | Variable orifice flow sensing apparatus |
| US5072737A (en) * | 1989-04-12 | 1991-12-17 | Puritan-Bennett Corporation | Method and apparatus for metabolic monitoring |
| US4909259A (en) * | 1989-04-21 | 1990-03-20 | Tehrani Fleur T | Method and apparatus for determining metabolic rate ratio |
| US5363857A (en) * | 1990-05-22 | 1994-11-15 | Aerosport, Inc. | Metabolic analyzer |
| US5226728A (en) * | 1991-11-04 | 1993-07-13 | Badger Meter, Inc. | Method and apparatus for measuring mass flow and energy content using a differential pressure meter |
| US5542284A (en) * | 1994-10-18 | 1996-08-06 | Queen's University At Kingston | Method and instrument for measuring differential oxygen concentration between two flowing gas streams |
| DE19545794C2 (en) * | 1995-12-08 | 1998-03-19 | Draegerwerk Ag | Gas sampling system with a mouthpiece |
| US20010044588A1 (en) * | 1996-02-22 | 2001-11-22 | Mault James R. | Monitoring system |
| FI102453B (en) * | 1997-03-17 | 1998-12-15 | Instrumentarium Oy | Improved measuring sensor and system for gas flow measurement |
| US6309360B1 (en) | 1997-03-17 | 2001-10-30 | James R. Mault | Respiratory calorimeter |
| US6572561B2 (en) | 1998-01-16 | 2003-06-03 | Healthetech, Inc. | Respiratory calorimeter |
| WO1999039637A1 (en) | 1998-02-05 | 1999-08-12 | Mault James R | Metabolic calorimeter employing respiratory gas analysis |
| WO2000007498A1 (en) | 1998-08-03 | 2000-02-17 | Mault James R | Method and apparatus for respiratory gas analysis employing measurement of expired gas mass |
| US6406435B1 (en) | 1998-11-17 | 2002-06-18 | James R. Mault | Method and apparatus for the non-invasive determination of cardiac output |
| US6220076B1 (en) | 1999-05-06 | 2001-04-24 | Queen's University At Kingston | Differential gas analyzer |
| US6517496B1 (en) | 1999-05-10 | 2003-02-11 | Healthetech, Inc. | Airway-based cardiac output monitor and methods for using same |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE814021C (en) * | 1948-10-02 | 1951-09-17 | Albert Dargatz Fa | Apparatus for measuring gas metabolism |
| FR1105567A (en) * | 1954-05-28 | 1955-12-05 | Centre Nat Rech Scient | Ion beam device for measuring gas volumes |
| DE1516428A1 (en) * | 1966-03-12 | 1969-08-28 | Medizintechnik Leipzig Veb | Device for measuring the mean respiratory time volume in both spontaneous and artificial breathing |
| DE1958888A1 (en) * | 1969-10-01 | 1971-04-08 | Medizintechnik Leipzig Veb | Tidal volume meter |
| DE1959244C3 (en) * | 1969-11-26 | 1973-09-13 | Siemens Ag, 1000 Berlin U. 8000 Muenchen | Calibration device for elektromedizim see gas pressure gauges |
| US3661528A (en) * | 1970-04-02 | 1972-05-09 | Instrumentation Associates Inc | Breath sampler |
| US3965749A (en) * | 1975-03-19 | 1976-06-29 | The United States Of America As Represented By The Secretary Of The Army | Sampling and dilution method |
| CA1069342A (en) * | 1976-07-29 | 1980-01-08 | Research Development Corporation | Variable orifice gas flow sensing head |
-
1978
- 1978-04-06 US US05/894,189 patent/US4197857A/en not_active Expired - Lifetime
-
1979
- 1979-03-23 CA CA324,064A patent/CA1108039A/en not_active Expired
- 1979-04-03 DE DE19792913208 patent/DE2913208A1/en not_active Withdrawn
- 1979-04-05 FR FR7908624A patent/FR2421593A1/en active Pending
- 1979-04-05 BE BE0/194414A patent/BE875336A/en not_active IP Right Cessation
- 1979-04-05 GB GB7912056A patent/GB2018426B/en not_active Expired
- 1979-04-06 JP JP4243479A patent/JPS54135489A/en active Granted
Also Published As
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|---|---|
| JPS54135489A (en) | 1979-10-20 |
| BE875336A (en) | 1979-07-31 |
| US4197857A (en) | 1980-04-15 |
| DE2913208A1 (en) | 1979-10-11 |
| JPS5549850B2 (en) | 1980-12-15 |
| FR2421593A1 (en) | 1979-11-02 |
| GB2018426B (en) | 1982-09-29 |
| GB2018426A (en) | 1979-10-17 |
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