WO2007051230A1

WO2007051230A1 - Sensing cuff for breathing apparatus

Info

Publication number: WO2007051230A1
Application number: PCT/AU2006/001615
Authority: WO
Inventors: Ian Malcolm Smith; Christopher Kingsley Blunsden; Adam Schindhelm
Original assignee: Resmed Ltd
Priority date: 2005-10-31
Filing date: 2006-10-27
Publication date: 2007-05-10

Abstract

A sensing cuff (12) for use with a breathing apparatus that delivers a supply of pressurized gas along a gas delivery path to a patient for treatment includes a conduit portion (30) adapted to be communicated with the gas delivery path and a sensing arrangement (40) provided to the conduit portion (30). The sensing arrangement (40) is configured to sense or sample one or more characteristics of the gas passing through the conduit portion (30) in use and wirelessly transmit characteristic data of the gas to a remote device.

Description

SENSING CUFF FOR BREATHING APPARATUS

CROSS REFERENCE TO APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No.

60/731 ,483, filed October 31 , 2005, which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

[0002] The present invention relates to a breathing apparatus that delivers breathable gas to a patient.

BACKGROUND OF THE INVENTION

[0003] Breathing apparatus to deliver breathable gas to a patient typically includes a flow generator, an air or gas delivery conduit, and a patient interface, hi use, the air delivery conduit delivers pressurized air or gas from the flow generator to the patient interface in contact with the patient's face.

[0004] The usual methods for sensing the physical parameters relating to delivered air conditions (e.g., pressure, temperature, humidity) involve electrical or pneumatic connections from the flow generator to the patient interface. For example, known methods for sensing the physical parameters include running small-bore air tubing between the flow generator and patient interface for pressure sensing, running small-bore air tubing between the flow generator and a fitting located somewhere along the air delivery conduit for pressure sensing, and running wiring from the flow generator to the patient interface, in which sensors are fitted, to detect pressure and possibly other parameters.

[0005] Such electrical or pneumatic connections typically add weight and bulk to the air delivery conduit and the patient interface causing patient discomfort and inconvenience. Such electrical or pneumatic connections also require special cleaning care, and are prone to unreliability due to the patient having to unmake/make connections. In addition, if electrical wiring is part of such connections, there may be issues with fragility at the connections. [0006] Another known method for sensing pressure is measuring pressure at the flow generator and then performing mathematical modeling to work out the pressure drop along the air delivery conduit to calculate the mask pressure and respiratory flow. A disadvantage of this method is that the modeling does not take into account the device-to-device variations in the air delivery conduit and the patient mask diffuser flow characteristics. Thus, this method leads to errors in measured mask pressure and respiratory flow.

[0007] Further, the system sensors currently reside in the flow generator with no direct information obtained about the patient's state of arousal during the night. Thus, the patient's state of arousal is inferred from detected events such as apneas or flow flattening, or from other characteristics of the air flow.

[0008] The present invention provides improvements to known breathing apparatus to overcome these limitations in order to enhance and/or facilitate the treatment session.

SUMMARY OF THE INVENTION

[0009] One aspect of the invention relates to a sensing cuff provided along the air delivery conduit that includes one or more wireless sensors that are wirelessly communicated with the flow generator.

[0010] Another aspect of the invention relates to a sensor provided to the patient interface that detects patient movement and sleeping position. [0011] Another aspect of the invention relates to a sensing cuff for use with a breathing apparatus that delivers a supply of pressurized gas along a gas delivery path to a patient for treatment. The sensing cuff includes a conduit portion adapted to be communicated with the gas delivery path and a sensing arrangement provided to the conduit portion. The sensing arrangement is configured to sense or sample one or more characteristics of the gas passing through the conduit portion in use and wirelessly transmit characteristic data of the gas to a remote device.

[0012] Another aspect of the invention relates to a method for operating a flow generator that generates a supply of pressurized gas to be provided along a gas delivery path to a patient for treatment. The method includes sensing or sampling one or more characteristics of the gas passing along the gas delivery path, wirelessly transmitting characteristic data of the gas to the flow generator, and operating the flow generator at least in part based on the characteristic data. [0013] Yet another aspect of the invention relates to a sensing arrangement for a patient interface. The sensing arrangement includes a pressure sensor configured to sense pressure at the patient interface in use and a silicone or other plastic membrane provided to the pressure sensor. The membrane forms a sheath around the pressure sensor so that the membrane shields the sensor from direct contact with air provided within the patient interface.

[0014] Other aspects, features, and advantages of this invention will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, which are a part of this disclosure and which illustrate, by way of example, principles of this. invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings facilitate an understanding of the various embodiments of this invention. In such drawings:

[0016] Fig. 1 is a schematic view of a breathing apparatus including a sensing cuff according to an embodiment of the present invention;

[0017] Fig. 2 is a top perspective view of a sensing cuff according to an embodiment of the present invention;

[0018] Fig. 3 is a cross-sectional view through line 3-3 in Fig. 2;

[0019] Fig. 4 is a block diagram of the sensing cuff shown in Fig. 2;

[0020] Fig. 5 is a perspective view of a sensing cuff according to an embodiment of the present invention;

[0021] Fig. 6 is a perspective view of a breathing apparatus including a sensing cuff according to another embodiment of the present invention;

[0022] Fig. 7 is a side perspective view of the sensing cuff shown in Fig. 6 removed from the breathing apparatus;

[0023] Fig. 8 is a front perspective view of the sensing cuff shown in Fig. 6 removed from the breathing apparatus; and

[0024] Fig. 9 is a cross-sectional view of a sensing arrangement according to another embodiment of the present invention. DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

[0025] Fig. 1 illustrates a breathing apparatus 10 including a sensing cuff 12 according to an embodiment of the present invention. The breathing apparatus 10 is structured to deliver a supply of pressurized breathable air or gas to a patient for treatment, e.g., of Sleep Disordered Breathing (SDB) with CPAP or Non-Invasive Positive Pressure Ventilation (NIPPV). The breathing apparatus 10 generally includes a flow generator 14, an air or gas delivery conduit 16, and a patient interface 18. As discussed in greater detail below, the sensing cuff 12 is provided along the air or gas delivery path of the breathing apparatus 10 and includes one or more wireless sensors that are wirelessly communicated with the flow generator 14 and/or other devices 20, e.g., gas mixture device, humidifier, data log, etc.

[0026] As is known in the art, the flow generator 14 is operable to provide a pressurized flow of air or gas at an outlet. The supply of pressurized air is delivered to the patient via an air delivery conduit 16 that includes one end communicated to the outlet of the flow generator 14 and an opposite end communicated to the patient interface 18. The patient interface 18 comfortably engages the patient's face and provides a seal in use. The patient interface 18 may have any suitable configuration as is known in the art, e.g., full-face mask, nasal mask, oro-nasal mask, mouth mask, nasal prongs, etc.

[0027] In the illustrated embodiment, the air delivery conduit 16 includes a first

, conduit 22 provided between the flow generator 14 and one end of the sensing cuff 12 and a second conduit 24 provided between the patient interface 18 and the other end of the sensing cuff 12 (see Figs. 1 and 2). However, the sensing cuff 12 may be provided along the air delivery path in other suitable manners. For example, the sensing cuff 12 may be provided between an. air delivery conduit and an air inlet, e.g., elbow, of a patient interface (e.g., see Fig. 6). The sensing cuff 12 is preferably placed as close to the patient interface, e.g., mask, as possible to ensure that the measured pressure is close to the mask pressure, i.e., to minimize the pressure drop along the air delivery conduit.

[0028] While the sensing cuff 12 is described as being implemented into a breathing arrangement 10 of the type described above, it may be implemented into other arrangements where it is desirable to sample conveyed gas or liquid and transmit that information to a controller for diagnostic and/or control purposes. That is, the breathing arrangement 10 is merely exemplary, and aspects of the present invention may be incorporated into any suitable arrangement.

1. First Illustrated Embodiment of Sensing Cuff

[0029] Figs. 2-4 illustrate a sensing cuff 12 according to an embodiment of the present invention. As best shown in Figs. 2-3, the sensing cuff 12 includes a conduit portion 30 communicated with the air delivery path and a sensing arrangement 40 provided to the conduit portion 30 that is configured to sense one or more characteristics or parameters of the air passing through the conduit portion 30 and wirelessly transmit characteristic data to the flow generator 14 and/or other device 20.

1.1 Conduit Portion

[0030] As shown in Fig. 2, the conduit portion 30, e:g., constructed of plastic, is a cylindrical tube or cuff removably connected between first and second conduits 22, 24 of the air delivery conduit 16. Specifically, the conduit portion 30 includes a first end 32, e.g., with a reduced diameter, that is removably connected to an end of the first conduit 22, and a second end 34 that is removably connected to an end of the second conduit 24. In use, pressurized air from the flow generator 14 passes through the first conduit 22, through the conduit portion 30, and through the second conduit 24 to the patient interface 18. Thus, the conduit portion 30 forms a portion of the air delivery path in use.

[0031] Also, the conduit portion 30 includes one or more holes, e.g., first and second holes 36, 38, along its length to allow the sensing arrangement 40 to sense or sample the air passing through the conduit portion 30.

1.2 Sensing Arrangement

[0032] As shown in Figs. 3 and 4, the sensing arrangement 40 includes a sensor network 42 providing one or more sensors, a micro-controller or electronic module 44 communicated with the sensor network 42 for receiving data, an RF transceiver or RF module 46 communicated with the micro-controller 44 for transmitting data from the micro-controller 44 to the flow generator 14 and/or other device 20, and a power supply 48 that provides power to the sensor network 42, micro-controller 44, and RF transceiver 46. [0033] The sensor network 42 includes one or sensors that sense one or more characteristics of the air passing through the conduit portion 30. For example, the sensor network 42 may include sensors to monitor air flow, pressure (e.g., relative to atmospheric pressure), temperature, humidity (e.g., relative or absolute), and/or specific gas concentrations (e.g., CO₂, 0₂). In an embodiment, the sensor network 42 may include a sensor in the form of a microphone that is configured to monitor the patient's snoring. However, other sensors are possible depending on application.

[0034] As shown in Fig. 3, the sensor network 40 includes a pressure sensor 50 and a humidity sensor 52. Each sensor 50, 52 includes a sampling tube 54, 56, respectively, that extends through a respective hole 36, 38 in the conduit portion 30 so that the sampling tubes 54, 56 are positioned in the air path. As illustrated, the pressure sensor 50 is supported in the hole 36-by an o-ring 58 to provide a pressure seal. However, other support arrangements are possible, hi an embodiment, one or more of the sensors in the sensing arrangement 40 may be covered by a thin silicone membrane or sheath to isolate the sensor from the air path (e.g., see embodiment of Fig. 9). The membrane maybe constructed from other suitable materials, e.g., even polycarbonate if the membrane is formed sufficiently thin. [0035] The micro-controller 44 is mounted to a shield or shroud 60 that encloses the sensing arrangement 40, e.g., by mounting members 62. The micro-controller 44 is communicated with the sensors 50, 52 in the sensor network 42, and controls and processes data collection by the sensors 50, 52. In an embodiment, the micro-controller 44 is in the form of an ultra low power mixed signal microprocessor that includes an internal temperature sensor and data acquisition channel (microphone). However, the micro-controller 44 may include more complex signal processing "smarts" or intelligence. [0036] In an embodiment, the sensing cuff 12 may incorporate an additional microprocessor into the system. Hence, functionality that previously was not included in the software due to processing power limitations could now be performed in the additional microprocessor, thereby further reducing external parts counts. For example, some hardware may be used to perform high pass filtering and RMS to DC conversion of a patient snore signal in order to allow a low sample rate from the main microprocessor to avoid overloading the main microprocessor. The sensing cuff could perform this signal processing in its secondary microprocessor prior to sending the processed information to the main microprocessor at the lower data rate.

[0037] The processed data from micro-controller 44 is communicated to the flow generator 14 and/or other device 20 via the RF transceiver 46. The RF transceiver 46 provides a wireless arrangement for transmitting data.

[0038] In an embodiment, the RF transceiver 46 operates with a spread spectrum or frequency hopping arrangement to reduce the chance of interference from other RF sources. For example, the RF transceiver 46 may have frequency bands of 403 MHz (international band for medical devices) and ~2 GHz. These high frequencies ensure that the antenna is physically small enough to fit inside the sensing cuff. In another embodiment, unlicensed frequency bands maybe used such as 420-450 MHz, 902-928 MHz, 2.4 MHz (2400-2485.5 MHz) and 5.8 GHz. Also, licensed frequency bands may be used but permission would be required.

[0039] In an embodiment, the RF transceiver 46 may be a transceiver manufactured by Nordic Semiconductors, such as nRF2401A with ShockBurst™ protocol. This is a 2.4 GHz transceiver and the ShockBurst™ feature is used in both receive and transmit mode to greatly simplify software and protocol design. The ShockBurst™ feature includes features for CRC computation in both receive and transmit mode, and addresses decoding in receive mode to greatly reduce the load and cost of the MCU running the RF protocol compared to existing transceivers in the market. Furthermore, the ShockBurst™ feature is capable of buffering up to 32 Bytes of payload coupled with short start-up times, which enables very low power duty cycled systems.

[0040] However, the RF transceiver 46 may have other suitable arrangements to transmit data. For example, a wireless link may be established using any suitable wireless protocol such as Bluetooth™ or Zigby™ protocols. It is noted that a transceiver (for talking both ways with the sensing cuff, e.g., configuring sensing cuff and reading data from sensing cuff) would be incorporated into the flow generator 14 and/or other device 20 to receive data transmitted by the RF transceiver 46. In alternative embodiments, data may be transmitted by the micro-controller 44 by other methods, e.g., wire to flow generator, fiber optics, etc. In another embodiment, data may be transmitted by Infra Red communication methods such as IRDA.

[0041] The power supply 48 provides power to the sensors 50, 52, micro-controller ^'

44, and RF transceiver 46 and may be in the form of one or more batteries, e.g., one or more AA or AAA batteries. The batteries may be primary (single use) or secondary (rechargeable) types. In an embodiment, power boost may be regulated to 3.3 V and 5 V. However, other power arrangements are possible. For example, power may potentially be generated from the air flow since the sensors typically only require very small amounts of power. [0042] The shield or shroud 60 that encloses the sensing arrangement 40 may be constructed of a similar material as the conduit portion 30, e.g., plastic, and may be secured and/or sealed to the conduit portion 30 in any suitable manner, e.g., mechanical interlock, adhesive. The shroud 60 is preferably water resistant to prevent damage to the sensor arrangement due to condensation in the air path and/or cleaning.

[0043] In use, the pressure sensor 50 collects pressure data and the humidity sensor 52 collects humidity data of the air passing through the conduit portion 30. This data is processed by the micro-controller 44, and then the data is wirelessly transmitted to the flow generator 14 and/or other device 20 via the RF transceiver 46. The flow generator 14 and/or other device 20, e.g., gas mixture device, humidifier, data log, etc., may use the data to optimize the operating parameters of the flow generator 12 and/or other device 20. The data may also be stored in a data log for analysis by a clinician. Thus, the sensing cuff 12 allows the flow generator 14 and/or other device 20 to operate more efficiently. However, the data may be used in other suitable manners in order to enhance and/or facilitate the treatment session.

[0044] The conduit portion 30 and enclosed sensing arrangement 40 provide the sensing cuff 12 with a structure that is robust, water-proof, cleanable and lightweight. As a result, the sensing cuff 12 may be placed anywhere along the air delivery path, e.g., using standard flexible hose fittings or male/female ISO standard taper-lock type fittings. Preferably, the sensing cuff 12 is placed close to the patient interface, e.g., mask, to minimize the pressure drop along the air delivery conduit. 1.3 Advantages

[0045] The sensing cuff 12 is superior to existing sensing arrangements for several reasons. For example, the sensing cuff 12 is wirelessly communicated with the flow generator 12 and/or other device 20 so it eliminates the bulk of additional commμnication tubing. This arrangement also eliminates issues relating to pneumatic or electrical connections at both the flow generator 14/other device 20 and the patient interface 18. In addition, the sensing cuff 12 can be made more robust and reliable than wires or tubing with connections.

[0046] The wireless arrangement also allows the sensing cuff 12 to communicate remotely with other medical devices, e.g., other devices 20, other than the flow generator 14. This allows other devices to utilize the data obtained from the sensors to enhance and/or facilitate the treatment session. For example, the sensing cuff 12 may communicate with implanted medical devices, e.g., pacemakers, to exchange information in order to better optimize therapy. In this arrangement, the sensing cuff 12 may need to use suitable RF bands for communication, e.g., medical implant band around 403 MHz. This aspect maybe particularly advantageous for physicians.

[0047] In addition, other wireless sensors may be provided in the breathing apparatus to provide additional data to the flow generator and/or other device. That is, the breathing apparatus may include other wireless sensors (not located in the sensing cuff 12), e.g., pulse oximeter or ECG leads, in order to avoid long cables communicating or running back to the flow generator and/or other device.

[0048] The sensing cuff 12 is also more accurate than known systems since the sensing cuff 12 is sensing parameters closer to the patient interface than systems which estimate a value for those parameters from measurements made by sensors located within the flow generator. [0049] The wireless arrangement of the sensing cuff 12 is more comfortable for the patient because it adds virtually no extra bulk and only a small extra weight. Also, if the sensing cuff 12 is placed a short distance away from the patient interface (e.g., 30-50 cm), then the extra weight of the sensing cuff 12 would be essentially unnoticed. In addition, the sensing cuff is easy to use for the patient, e.g., lack of connections, easy cleaning. In an embodiment, user IO buttons may be provided on the sensing cuff 12 to make it easier for the patient to control the breathing apparatus during the night.

[0050] The sensing cuff 12 provides better accuracy of air parameters including pressure and humidity. In particular, if the absolute humidity level is sensed (either directly with a sensor, or calculated from sensing the air relative humidity (RH) and temperature), then control of a humidifier can be closed-loop resulting in significant advantages. For example, the breathing arrangement can adjust the heater power to maintain through the night as the patient's original subjective setting, or adjust the heater power to maintain a specific humidity level during the course of the night. The value of set humidity (e.g., in mg/L water in air density) can be either marked on the humidifier controls, or an optimum value for clinical benefit/comfort can be provided as a 'default' setting.

[0051] Further, with the absolute humidity known close to the patient interface (or otherwise within the air delivery conduit), then the system can also reduce heater power as necessary to eliminate condensation of water in the air delivery conduit ('rain-out'). [0052] The sensing cuff 12 also provides several advantages to the physician. For example, the sensing cuff 12 is easy to administer, e.g., lack of connections. The sensing cuff 12 may be offered as an upgrade module that adds on to a base model by connecting an RF module in the flow generator at the external module port. The sensing cuff 12 provides improved compliance due to more comfortable hardware compared to systems with additional small tubing. The sensing cuff 12 also provides improved compliance in a system sensing the humidity level, due to optimized control over the humidity level throughout, the night. This results in reduced incidence of dry, sore throat, airway irritability, and reduced mucous production.

[0053] Another advantage of the sensing cuff 12 is that it provides the potential for monitoring gas concentrations remotely, i.e., without electrical connections back to the flow generator, which may offer a safety advantage over systems whereby O₂ levels are being monitored that involve electrical wiring in proximity to the main power via the flow generator. The sensing cuff 12 also provides the potential for monitoring gas concentrations remotely from a separate device, e.g., other device 20.

[0054] The compact structure of the sensing cuff 12 may also provide cost advantages, e.g., cheaper.

[0055] A further advantage relates to the ability to use a small bore air delivery conduit as the sensing cuff can measure pressure, etc., at the mask to ensure that the flow generator is accurately compensating for the large pressure drop along the small bore air delivery conduit. Such a small bore air delivery conduit is described in U.S. Patent Application. No. 60/707,950, filed August 15, 2005, the entirety incorporated herein by reference. The traditional method of calculating the pressure drop from measured values in the flow generator may not work accurately enough with a small bore air delivery conduit.

1.4 Activity Sensor

[0056] In an embodiment, the sensing cuff 12 may be provided with an activity sensor that detects patient movement and sleeping position or orientation. The activity sensor may be implemented using an accelerometer (e.g., 2 or 3 axis) to detect the patient's sleeping position or orientation (e.g., left side, right side, stomach, or back) as well as events such as movements during the night, which correlate with arousal (e.g., movement of the head). [0057] Silicon accelerometers respond to movement (e.g., acceleration) as well as the effect of gravity at different orientations. From the relative changes in the 3 axis readings (X, Y, and Z), the orientation of the patient's head can be inferred provided the sensing cuff is positioned close enough to the patient interface, e.g., mask. Erratic movements that become apparent during arousal (e.g., head movements) may also be detected. [0058] These metrics and events could then be correlated with other information, e.g., patient sleeping position and apnea events, to gain more insight into the particular circumstances of the patient. The activity sensor could also provide some objective feedback on the benefit of different therapy settings, e.g., the relative restlessness could be logged and compared under different therapy settings during the night.

[0059] The activity sensor could be battery powered and the collected data could be transmitted via the RF transceiver 46 back to the flow generator 14 and/or other device 20 as described above. In another embodiment, the activity sensor may be a remote sensor provided at the patient interface.

[0060] The activity sensor provides several advantages to the patient. For example, the activity sensor may be incorporated into the wireless sensing cuff 12 which makes it comfortable for the patient and easy to use. In use, the activity sensor provides the patient with feedback about his/her restlessness during sleep, and therapy can be better tailored to the patient's needs.

[0061] The activity sensor also provides several advantages to the physician. For example, the activity sensor may be incorporated into the wireless sensing cuff 12 which makes it easy for the physician to administer. The activity sensor provides the physician with more objective information about how restless the patient was during the night so the therapy can be more optimized. Also, the therapy settings could be automatically adjusted during the night by the system and the arousal monitored. The physician can then correlate arousal with therapy settings and determine the most effective compromise between comfort and treatment.

2. Second Illustrated Embodiment of Sensing Cuff

[0062] Fig. 5 illustrates another embodiment of a sensing cuff 212. As illustrated, the conduit portion 230 of the sensing cuff 212 is in the form of a basic cylindrical cuff fitting that provides opposing ends 232, 234 with a reduced diameter for removable connection between first and second conduits of an air delivery conduit. Similar to the above, the conduit portion 230 is provided with a sensing arrangement 240 including one or more sensors. As illustrated, the sensing cuff 212 provides an overall small, cleanable, and unobtrusive fitting.

3. Third Illustrated Embodiment of Sensing Cuff

[0063] Figs. 6-8 illustrate a sensing cuff 312 according to another embodiment. As best shown in Fig. 6, the conduit portion 330, e.g., constructed of plastic, includes a first end 332, e.g., with a reduced diameter, that is removably connected to an end of the air delivery conduit 316, and a second end 334 that is removably connected to the swivel 327 of an elbow 326 coupled to the patient interface 318. Also, the conduit portion 330 includes a hole or port 336 that allows a sensing arrangement 340 to sense or sample the air passing through the conduit portion 330. However, the conduit portion 330 may include more than one hole or port for air sampling purposes.

[0064] The sensing arrangement 340, similar to sensing arrangement 40, includes one or more wireless sensors (e.g., pressure, humidity, etc.) that sample air through the one or more ports 336 of the conduit portion 330. In the illustrated embodiment, the shroud or housing 360 of the sensing arrangement 340 encloses a battery power source. A removable cover plate 361 is provided to the housing 360 for battery access in order to facilitate periodic battery replacement.

[0065] hi another embodiment, the sensing arrangement may attach onto, e.g., clip onto, the air delivery conduit and a short length of tube may extend to the patient interface, e.g., mask, to sense the mask pressure.

4. Sensing Arrangement at the Patient Interface

[0066] Fig. 9 illustrates a sensing arrangement 440 according to another embodiment of the present invention. In the illustrated embodiment, the sensing arrangement 440 includes a pressure sensor 450 configured to sense pressure at the patient interface, e.g., mask 418, and a thin silicone membrane or sheath 470 around the sensor 450. The membrane may be constructed from other suitable materials, e.g., polycarbonate if the membrane is formed sufficiently thin.

[0067] A typical problem for sensors at the patient interface is the disinfection of the sensor. As illustrated, the sensor 450 is shielded from direct contact with the delivered air. Specifically, the sensor 450 is isolated from the mask air by the thin silicone membrane 470 that forms a sheath around the sensor 450. The sensor 450 may have a jagged or threaded exterior surface to secure the sensor 450 to the membrane 470. Moderate air-tightness between the membrane 470 and the mask frame 419 and between the membrane 470 and the sensor 450 ensure pressure coupling across the membrane 470. A bleed hole may be provided between membrane 470 and the sensor 450 to prevent trapped pressure within the sensor chamber. The membrane 470 may either be cleaned or discarded between patients. [0068] As illustrated, the sensor 450 and membrane 470 are retained within a mounting structure 421 provided to the mask frame 419. The sensor 450 includes a handle or extension 451 to facilitate mounting and removing the sensor arrangement 440 to the mounting structure 421. The mask frame 419 includes an opening 423 that allows the sensor 450 to communicate with the mask air. The membrane 470 has a thin or stretched section 472 that passes over the opening 423 to shield the sensor 450 from the mask air. However, the stretched section 472 allows pressure sensor 450 to sense pressure in the mask. [0069] A sensor cable 480 communicates data from the sensor 450 to a remote device, e.g., flow generator. A strain relief 482 may be provided to help prevent cable damage, hi another embodiment, the data may be wirelessly communicated to a remote device, e.g., via an RF transceiver.

[0070] It is noted that the wireless sensing arrangement 40 described above may also be incorporated or built into the patient interface, e.g., mask. That is, the wireless sensing arrangement 40 maybe provided to the mask rather than along the air delivery conduit or inline hose. This arrangement may be the best configuration for the activity sensor as the mask is secured to the patient's head to allow the activity sensor to best track the patient's head movements.

[0071] While the invention has been described in connection with what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. Also, the various embodiments described above may be implemented in conjunction with other embodiments, e.g., aspects of one embodiment may be combined with aspects of another embodiment to realize yet other embodiments. In addition, while the invention has particular application to patients who suffer from OSA, it is to be appreciated that patients who suffer from other illnesses (e.g., congestive heart failure, diabetes, morbid obesity, stroke, barriatric surgery, etc.) can derive benefit from the above teachings. Moreover, the above teachings have applicability with patients and non-patients alike in nonmedical applications.

Claims

WHAT IS CLAIMED IS:

1. A sensing cuff for use with a breathing apparatus that delivers a supply of pressurized gas along a gas delivery path to a patient for treatment, the sensing cuff comprising: a conduit portion adapted to be communicated with the gas delivery path; and a sensing arrangement provided to the conduit portion, the sensing arrangement configured to sense or sample one or more characteristics of the gas passing through the conduit portion in use and wirelessly transmit characteristic data of the gas to a remote device.

2. The sensing cuff according to claim 1 , wherein the conduit portion includes one or more holes or ports along its length to allow the sensing arrangement to sense or sample the gas passing through the conduit portion.

3. The sensing cuff according to any one of claims 1 -2, wherein the conduit portion is a cylindrical tube having first and second ends.

4. The sensing cuff according to claim 3, wherein the first end has a smaller . diameter than the second end.

5. The sensing cuff according to any one of claims 1-4, wherein the sensing arrangement includes a sensor network providing one or more sensors that sense one or more characteristics of the gas passing through the conduit portion, a micro-controller communicated with the sensor network for receiving characteristic data, an RF transceiver communicated with the micro-controller for wirelessly transmitting the characteristic data from the micro-controller to the remote device, and a power supply that provides power to the sensor network, micro-controller, and RF transceiver.

6. The sensing cuff according to claim 5, wherein the one or more sensors monitor at least one of gas flow, pressure, temperature, humidity, specific gas concentrations, and patient snoring.

7. The sensing cuff according to any one of claims 5-6, wherein the microcontroller controls and processes data collection by the sensors.

8. The sensing cuff according to any one of claims 5-7, wherein the power supply includes one or more batteries.

9. The sensing cuff according to any one of claims 5-8, further comprising a shroud that encloses the sensing arrangement.

10. The sensing cuff according to any one of claims 5-9, wherein the one or more sensors includes an activity sensor that detects patient movement and sleeping position.

11. The sensing cuff according to claim 10, wherein the activity sensor includes an accelerometer.

12. A breathing apparatus comprising: a flow generator that generates a supply of pressurized air; a patient interface engagable with a patient's face to provide a seal; an air delivery conduit provided between the flow generator and the patient interface to deliver the supply of pressurized air along a gas delivery path from the flow generator to the patient interface; and the sensing cuff according to any one of claims 1-11.

13. The breathing apparatus according to claim 12, wherein the remote device is the flow generator, the flow generator including a transceiver to receive characteristic data transmitted by the sensing arrangement.

14. The breathing apparatus according to any one of claims 12-13, wherein the remote device is at least one of a gas mixture device, humidifier, and data log.

15. The breathing apparatus according to any one of claims 12-14, wherein the air delivery conduit includes a first conduit provided between the flow generator and one end of the conduit portion and a second conduit provided between the patient interface and the other end of the conduit portion.

16. The breathing apparatus according to any one of claims 12-14, wherein the conduit portion is provided between the air delivery conduit and an elbow of the patient interface.

17. A method for operating a flow generator that generates a supply of pressurized gas to be provided along a gas delivery path to a patient for treatment, the method comprising: sensing or sampling one or more characteristics of the gas passing along the gas delivery path; wirelessly transmitting characteristic data of the gas to the flow generator; and operating the flow generator at least in part based on the characteristic data.

18. A sensing arrangement for a patient interface, comprising: a pressure sensor configured to sense pressure at the patient interface in use; and a silicone or other plastic membrane provided to the pressure sensor, wherein the membrane forms a sheath around the pressure sensor so that the membrane shields the sensor from direct contact with air provided within the patient interface.

19. The sensing arrangement according to claim 18, wherein the sensor is communicated with the air provided within the patient interface via an opening provided to the patient interface, and the membrane includes a thin or stretched section that passes over the opening to shield the sensor from direct contact with the air.

20. The sensing arrangement according to any one of claims 18-19, further comprising a sensor cable that communicates data from the sensor to a remote device.

21. The sensing arrangement according to any one of claims 18-19, wherein data from the sensor is wirelessly communicated to a remote device.

22. A mask assembly, comprising: a mask frame; a face-contacting portion provided to the mask frame; and the sensing arrangement according to any one of claims 18-21, wherein the mask frame includes a mounting structure to mount the sensing arrangement.