Methods and apparatus for controlling mask leak in CPAP treatment

Patent metadata

Field	Value
Publication number	US-10342941-B2
Application number	US-201414298115-A
Country	US
Kind code	B2
Filing date	Jun 6, 2014
Priority date	Jun 14, 2005
Publication date	Jul 9, 2019
Grant date	Jul 9, 2019

Abstract

A method of operating a device for treating sleep disordered breathing (SDB), wherein the device provides continuous positive airway pressure during sleep, includes determining whether treatment pressure at the patient interface is below a desired value, in response to the determining, increasing pressure generated by the flow generator, in response to the increasing, making a determination that the increase in flow generator pressure has resulted in less than a desired increase in treatment pressure at the patient interface, and in response to the determination, reducing or inhibiting further increase of the flow generator pressure.

First claim

What is claimed is:

1. An apparatus configured for sealed delivery of a flow of breathable gas at a continuously positive pressure with respect to ambient air pressure to an entrance of a patient's airways including at least an entrance of the patient's nares while the patient is sleeping to treat sleep disordered breathing (SDB), the apparatus comprising:
a blower configured to generate and pressurize the flow of breathable gas; and
a controller configured to (1) adjust the blower to increase the pressure of the breathable gas when a treatment pressure is below a predetermined threshold, (2) determine whether the increase in the pressure of the breathable gas resulting from the adjustment of the blower is less than a predetermined increase in the treatment pressure and (3) generate the flow of breathable gas at a reduced positive pressure or inhibit a further increase in the pressure of the breathable gas when the increase in pressure resulting from the adjustment of the blower is less than the predetermined increase in the treatment pressure.

2. The apparatus according to claim 1 , wherein the controller is configured to adjust the blower based on a comparison between a leak parameter and a leak threshold.

3. The apparatus according to claim 2 , wherein the leak parameter is a mask leak impedance parameter.

4. The apparatus according to claim 2 , wherein the leak threshold is based on a patient arousal index.

5. The apparatus according to claim 4 , wherein the patient arousal index includes at least one of an Apnea Hypopnea Index (AHI) and a sleep phase index of the patient.

6. The apparatus according to claim 5 , wherein the sleep phase index is based on at least one of: brain waves of the patient and respiration of the patient.

7. The apparatus according to claim 5 , wherein the patient arousal index is based on body position.

8. The apparatus according to claim 5 , wherein the patient arousal index is based on snoring.

9. The apparatus according to claim 2 , wherein the leak threshold varies as a function of indications of a flow limitation.

10. The apparatus according to claim 9 , wherein the indications of a flow limitation include flow flattening, snore, apnea, hypopnea, and/or Apnea Hypopnea Index (AHI).

11. The apparatus according to claim 2 , wherein the controller is configured to adjust the leak threshold or turn off a leak control function.

12. The apparatus according to claim 2 , wherein the controller is configured to maintain a record of incidents where the blower is adjusted to reduce the pressure of the breathable gas in response to an excessive leak for subsequent review by a clinician to facilitate patient interface selection and/or adjustment for the patient.

13. The apparatus according to claim 2 , wherein the controller is configured to operate in one or more leak control modes.

14. The apparatus according to claim 13 , wherein the one or more leak control modes are selectable depending on patient preference and/or compliance levels.

15. The apparatus according to claim 13 , wherein the one or more leak control modes includes a first mode in which the controller adjusts the blower to reduce the pressure of the breathable gas upon detection of a leak and maintain the pressure of the breathable gas at a level below a full-therapeutic pressure to allow a patient interface to seal against the patient's face.

16. The apparatus according to claim 13 , wherein the one or more leak control modes includes a second mode in which the controller adjusts the blower to reduce the pressure of the breathable gas to a sub-therapeutic pressure for a brief predetermined period to allow a patient interface to reseal against the patient's face, and then ramp back up to a full-therapeutic pressure.

17. The apparatus according to claim 16 , wherein the brief predetermined period is 15-60 seconds.

18. The apparatus according to claim 13 , wherein the one or more leak control modes includes a third mode in which the controller adjusts the blower to reduce the pressure of the breathable gas upon detection of a leak in excess of the leak threshold to a ramp start pressure used for commencement of a therapy session, and then ramp back up to full therapeutic pressure over a shortened ramp time.

19. The apparatus according to claim 18 , wherein the shortened ramp time is 50% of a ramp time used at the commencement of the therapy session.

20. The apparatus according to claim 13 , wherein the one or more leak control modes includes a fourth mode in which the controller adjusts the blower to reduce the pressure of the breathable gas by a set increment upon detection of a leak in excess of the leak threshold, measure the leak parameter for a set period of time, and further incrementally reduce the pressure of the breathable gas if the leak remains above the leak threshold.

21. The apparatus according to claim 20 , wherein the set increment is 1 cmH 2 O.

22. The apparatus according to claim 2 , wherein the controller is configured to adjust the blower to re-increase the pressure of the breathable gas to re-assess a patient interface-to-patient seal after a predetermined period of operation below the leak threshold.

23. The apparatus according to claim 1 , wherein the apparatus further comprises:
a patient interface configured to sealingly engage the patient's face; and
an air delivery tube fluidly connected to the blower and configured to deliver the pressurized breathable gas to the patient interface.

24. The apparatus according to claim 23 , wherein the controller is configured to operate in a patient interface fitting operational mode in which the controller controls the blower to apply a normal range treatment pressure in order to perform a patient interface seal testing and patient interface fitting regimen and fit the patient interface to the patient in a clinical setting.

25. The apparatus according to claim 24 , wherein the controller is configured to adjust the blower to limit a flow rate of the breathable gas to a flow approximately equal to or slightly above a vent flow rate for the patient interface.

26. The apparatus according to claim 23 , wherein the controller is configured to adjust the blower to maintain a therapy pressure at the patient interface in a range of about 2 cmH 2 O to about 40 cmH 2 O above ambient air pressure.

27. The apparatus according to claim 23 , further comprising a pressure sensor configured to detect a pressure of the breathable gas at the patient interface.

28. The apparatus according to claim 23 , wherein said less than a predetermined increase in the treatment pressure is indicative of a greater than desired gas leak or increase in gas leak at the patient interface.

29. The apparatus according to claim 1 , further comprising a flow sensor positioned downstream of the blower, the flow sensor being configured to detect a flow rate of the pressurized breathable gas provided by the blower.

30. The apparatus of claim 1 , wherein the reduced positive pressure is sufficient to provide airway support to the patient during sleep disordered breathing therapy.

31. An apparatus configured for sealed delivery of a flow of breathable gas at a continuously positive pressure with respect to ambient air pressure to an entrance of a patient's airways including at least an entrance of the patien

Assignees

• ResMed Pty Ltd

Inventors

• Kwok Philip Rodney
• Richard Ron
• Selvarajan Karthikeyan
• Richards Glenn
• Reed Nicholas Jerome
• Puckeridge Larry

Classifications

• A61M16/0875

  Connecting tubes · CPC title

• A61B5/4818

  Sleep apnoea · CPC title

• A61M16/0003

  Accessories therefor, e.g. sensors, vibrators, negative pressure · CPC title

• A61M16/0069 Primary

  the speed thereof being controlled by respiratory parameters, e.g. by inhalation · CPC title

• A61B5/4812

  Detecting sleep stages or cycles · CPC title