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 method for sealing a patient interface with respect to a patient, comprising:
providing the patient interface with an inflatable bladder configured to engage the face of the patient, the bladder having a side wall, and the side wall being thinner in a face contacting region of the bladder than in a face non-contacting region, the side wall thickness being progressively thicker from the face contacting region to the face non-contacting region, wherein a rate of the thickening of the side wall varies around the face contacting region of the bladder; and
pressurizing the bladder to a pressure that exceeds an instantaneous pressure to be applied to an interior of the patient interface by a positive amount, the pressure being chosen so that the patient interface seals comfortably at any instantaneous pressure applied to the interior of the patient interface.
2. The method as claimed in claim 1 , wherein the positive amount is a constant amount over an entire range of instantaneous pressures.
3. The method as claimed in claim 1 , further comprising forming the inflatable bladder in the form of a hollow a quasi-toroidal bladder.
4. A method for sealing a mask to a patient comprising:
providing a mask with a sealing element including a bladder configured to engage the face of the patient, the bladder having a side wall, and the side wall being thinner in a face contacting region of the bladder than in a face non-contacting region, the side wall thickness being progressively thinner from the face non-contacting region to the face contacting region, wherein a rate of the thickening of the side wall varies around the face contacting region of the bladder;
pressurizing the bladder to a bladder pressure; and
adjusting the bladder pressure in accordance with a range of instantaneous pressures to be applied to an interior of the mask, to thereby adaptively seal a portion of the mask against the patient's face.
5. A method as claimed in claim 4 , wherein the bladder pressure is offset from the instantaneous pressures by a positive amount.
6. A method as claimed in claim 5 , wherein the positive offset amount is a constant amount over the range of instantaneous pressures.
7. A method as claimed in claim 5 , wherein the positive offset amount increases with increases to the instantaneous pressures.
8. A method for adjusting the sealing force applied to a patient by a patient interface, comprising:
providing a sealing element with an inflatable bladder configured to engage the patient's face, the bladder having a side wall, and the side wall being thinner in a face contacting region of the bladder than in a face non-contacting region, the side wall thickness being progressively thicker from the face contacting region to the face non-contacting region, wherein a rate of the thickening of the side wall varies around the face contacting region of the bladder, and
pressurizing the bladder to a pressure which exceeds an instantaneous pressure to be applied to an interior of the sealing element by an amount that increases with increasing instantaneous pressure.
9. The method of claim 8 , wherein the bladder pressure may be an affine function of the instantaneous pressure.
10. An apparatus comprising:
a blower to deliver an instantaneous pressure to a user; and
a user interface including an inflatable element configured to engage the user's face, the inflatable element having a side wall, and the side wall being thinner in a face contacting region of the inflatable element than in a face non-contacting region, the side wall thickness being progressively thicker from the face contacting region to the face non-contacting region, wherein a rate of the thickening of the side wall varies around the face contacting region of the inflatable element, and under a positive offset pressure that is higher than the instantaneous pressure to thereby maintain a seal between the user's face and the user interface.
11. The apparatus of claim 10 , further comprising a weighted or spring-loaded piston.
12. The apparatus of claim 10 , further comprising a balloon, wherein the positive offset pressure is derived from recoil pressure of the balloon.
13. The apparatus of claim 10 , further comprising an impedance pump.
14. The apparatus of claim 13 , wherein the low impedance pump includes at least one of a centrifugal and/or an axial fan.
15. The apparatus of claim 10 , further comprising an impedance pump provided with an impedance bypass configured to remove oscillations induced by the impedance pump.
16. The apparatus of claim 15 , wherein the impedance bypass includes at least on of a spring-loaded blow-off valve and/or a water-trap blow-off valve.
17. The apparatus of claim 10 , further comprising at least one of a weighted and/or spring-loaded piston or balloon, in parallel with an impedance pump and/or an adjustable shunt.
18. The apparatus of claim 17 , wherein the adjustable shunt includes at least one of a valve, a spring-loaded blow-off valve, and/or a water-trap blow-off valve.
19. The apparatus as claimed in claim 10 , wherein the positive offset pressure is constant over an entire range of the instantaneous pressures.
20. The apparatus as claimed in claim 10 , wherein the positive offset pressure varies with changes in the instantaneous pressure.
21. The apparatus of claim 20 , wherein the positive offset pressure is between about 1-10 cmH 2 O.
22. A mask assembly comprising:
a frame;
a cushion provided to the frame and defining a nasal chamber subject to an instantaneous pressure; and
a bladder configured to engage the face of a wearer of the mask assembly, the bladder having a side wall, and the side wall being thinner in a face contacting region of the bladder than in a face non-contacting region, the side wall thickness being progressively thicker from the face contacting region to the face non-contacting region, wherein a rate of the thickening of the side wall varies around the face contacting region of the bladder, the bladder being associated with the cushion and subject to a bladder pressure that is higher than the instantaneous pressure.
23. The apparatus of claim 22 , wherein the bladder pressure is a fixed amount above the instantaneous pressure.
24. The apparatus of claim 23 , wherein the fixed amount is about 5 cmH 2 O.
25. The apparatus of claim 22 , wherein the bladder is configured such that the bladder pressure variably changes with changes in the instantaneous pressure.
26. The apparatus of claim 25 , wherein the bladder pressure ranges from about 1-10 cmH 2 O.
27. The apparatus of claim 26 , wherein the bladder pressure ranges from about 3-8 cmH 2 O.
28. The apparatus of claim 22 , wherein the bladder pressure is dependent on the instantaneous pressure.
29. A method for sealing a patient interface with respect to a patient, comprising:
providing the patient interface with an inflatable bladder, the bladder having a side wall, and the side wall being thinner in a face contacting region of the bladder than in a face non-contacting region, the side wall thickness being progressively thicker from the face contacting region to the face non-contacting region, wherein a rate of the thickening of the side wall varies around the face contacting region of the bladder;
engaging the face of the patient with the inflatable bladder;
pressurizing the bladder to a pressure that exceeds an instantaneous pressure to be applied to an interior of the patient interface by a positive amount, the amount being chosen so that the patient interface seals comfortably at any instantaneous pressure applied to the interior of the patient interface.
30. A method according to claim 29 , wherein the positive amount is a constant amount over an entire range of instantaneous pressures.