Method and apparatus for adjusting respiratory mask sealing force
View Patent ↗A mask assembly includes a mask with an inflatable bladder. The internal pressure of the inflatable bladder can be set to be higher than the delivered therapeutic pressure. The pressure offset may be constant, or it may vary over the range of therapeutic pressures. Thus, the force necessary to maintain a contact seal between the mask and the patient can be reduced, thereby providing a system that is more comfortable to the patient, which increases patient compliance.
1. A patient interface for delivering 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, throughout the patient's respiratory cycle, while the patient is sleeping, to ameliorate sleep disordered breathing to the patient, the patient interface comprising:
a cushion with a bladder, the cushion being configured to sealingly engage the patient's face and the bladder being defined by a sidewall with a varied thickness, a portion of the sidewall being configured to seal against the patient's face;
a chamber defined at least in part by the cushion, the chamber structured to communicate the positively pressurized breathable gas to the patient's airways;
a port configured to convey pneumatic signals corresponding to a first gas pressure in the chamber, the pneumatic signals being indicative of the patient's respiratory phase; and
headgear configured to secure the patient interface to the patient's head,
wherein the cushion with the bladder is configured to cooperate with the headgear to generate and adjust a force against the patient's face as a function of the pneumatic signals conveyed by the port, the force being sufficient to maintain a seal between the patient's face and the patient interface.
2. A patient interface according to claim 1 , wherein the cushion with the bladder is configured to cooperate with the headgear to increase the force against the patient's face as the first gas pressure in the chamber increases.
3. A patient interface according to claim 2 , wherein the cushion with the bladder is configured to cooperate with the headgear to increase the force against the patient's face at a faster rate than a rate of increase of the first gas pressure in the chamber.
4. A patient interface according to claim 1 , wherein the cushion with the bladder is configured to cooperate with the headgear to decrease the force against the patient's face as the first gas pressure in the chamber decreases.
5. A patient interface according to claim 1 , wherein the cushion is configured to maintain a second gas pressure within the bladder that is greater than the first gas pressure in the chamber by an offset value.
6. A patient interface according to claim 5 , wherein a magnitude of the headgear tension is related to the second gas pressure in the bladder.
7. A patient interface according to claim 6 , wherein a magnitude of the force against the patient's face is related to the headgear tension and the second gas pressure in the bladder.
8. A patient interface according to claim 7 , wherein the force against the patient's face is a minimum force necessary to achieve the seal between the patient's face and the patient interface at the instant first gas pressure in the chamber.
9. A patient interface according to claim 8 , wherein the offset value is constant.
10. A patient interface according to claim 8 , wherein the offset value is variable as a function of the first gas pressure in the chamber.
11. A patient interface according to claim 10 , wherein the cushion is configured to increase the offset value as the first gas pressure in the chamber increases.
12. A patient interface according to claim 1 , wherein the bladder sidewall is progressively thinner toward a side of the cushion configured to engage the patient's face.
13. A patient interface system according to claim 1 , wherein the first gas pressure is maximal during an inspiration phase of the patient's respiratory cycle and is minimal during an exhalation phase of the patient's respiratory cycle.
14. A patient interface for delivering 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, throughout the patient's respiratory cycle, while the patient is sleeping, to ameliorate sleep disordered breathing to the patient, the patient interface comprising:
a cushion with a bladder, the cushion being configured to sealingly engage the patient's face and the bladder being defined by a sidewall with a varied thickness, a portion of the sidewall being configured to seal against the patient's face;
a chamber defined at least in part by the cushion, the chamber structured to communicate the positively pressurized breathable gas to the patient's airways; and
headgear configured to secure the patient interface to the patient's head,
wherein the cushion with the bladder is configured to cooperate with the headgear to generate and adjust a force against the patient's face as a function of the patient's respiratory phase, the force being sufficient to maintain a seal between the patient's face and the patient interface.
15. A patient interface according to claim 14 , wherein the cushion with the bladder is configured to cooperate with the headgear to increase the force against the patient's face during inspiration.
16. A patient interface according to claim 14 , wherein the cushion with the bladder is configured to cooperate with the headgear to decrease the force against the patient's face during expiration.
17. A patient interface according to claim 14 , wherein the cushion is configured to maintain a second gas pressure within the bladder that is greater than a first gas pressure in the chamber.
18. A patient interface according to claim 17 , wherein a magnitude of the headgear tension is related to the second gas pressure in the bladder.
19. A patient interface according to claim 18 , wherein a magnitude of the force against the patient's face is related to the headgear tension and the second gas pressure in the bladder.
20. A patient interface according to claim 19 , wherein the force against the patient's face is a minimum force necessary to achieve the seal between the patient's face and the patient interface at the instant first gas pressure in the chamber.
21. A patient interface according to claim 14 , wherein the headgear comprises extensible straps.
22. A patient interface according to claim 14 , wherein the headgear comprises inextensible straps.
23. A patient interface according to claim 14 , wherein the bladder sidewall is progressively thinner toward a side of the cushion configured to engage the patient's face.
24. A patient interface for delivering 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, throughout the patient's respiratory cycle, while the patient is sleeping, to ameliorate sleep disordered breathing to the patient, the patient interface comprising:
a cushion with a bladder, the cushion being configured to sealingly engage the patient's face and the bladder being defined by a sidewall with a varied thickness, a portion of the sidewall being configured to seal against the patient's face;
a chamber defined at least in part by the cushion, the chamber structured to communicate the positively pressurized breathable gas to the patient's airways;
headgear configured to secure the patient interface to the patient's head; and
a controller configured to adjust a second gas pressure in the bladder to generate and adjust, in conjunction with the headgear, a force against the patient's face based on a detected first gas pressure in the chamber, the force being sufficient to maintain a seal between the patient's face and the patient interface,
wherein the controller is configured so that the second gas pressure is variable as a function of the patient's breathing phase.
25. A patient interface according to claim 24 , further comprising a sensor configured to generate a signal indicative of the first gas pressure in the chamber, the controller adjusting the second gas pressure in the bladder based on the generated signal.
26. A patient interface according to claim 25 , wherein the controller is configured to adjust the second gas pressure in the bladder to increase, in conjunction with the headgear, the force against the patient's face as the first gas pressure in the chamber increases.
27. A patient interface according to claim 26 , wherein the controller is configured to adjust the second gas pressure in the bladder to increase, in conjunction with the headgear, the force against the patient's face at a faster rate than a rate of increase of the first gas pressure in the chamber.
28. A patient interface according to claim 26 , wherein the controller is configured to adjust the second gas pressure in the bladder to decrease, in conjunction with the headgear, the force against the patient's face as the first gas pressure in the chamber decreases.
29. A patient interface according to claim 26 , wherein the controller is configured to maintain the second gas pressure within the bladder at a level greater than the first pressure in the chamber by an offset value.
30. A patient interface according to claim 24 , wherein the bladder sidewall is progressively thinner toward a side of the cushion configured to engage the patient's face.
31. A patient interface system for delivering 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, throughout the patient's respiratory cycle, while the patient is sleeping, to ameliorate sleep disordered breathing to the patient, the patient interface comprising:
the patient interface of claim 1 ; and
a source of positively pressurized gas,
wherein the cushion is in pneumatic communication with the source of positively pressurized gas, and
wherein the source of positively pressurized gas is configured to vary the first gas pressure as a function of the patient's respiratory phase within the patient's respiratory cycle.
32. A patient interface system for delivering 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, throughout the patient's respiratory cycle, while the patient is sleeping, to ameliorate sleep disordered breathing to the patient, the patient interface comprising:
the patient interface of claim 14 ; and
a source of positive pressure gas,
wherein the cushion is in communication with the source of positive pressure gas,
wherein the source of positive pressure gas and the cushion with the bladder are configured to cooperate with the headgear to generate and adjust the force against the patient's face as a function of the patient's respiratory phase, the force being sufficient to maintain a seal between the patient's face and the patient interface.