Determination of mask fitting pressure and correct mask fit

• US 20060254588A1
• Filed: 07/18/2006
• Published: 11/16/2006
• Est. Priority Date: 12/21/1998
• Status: Active Grant

• Current Assignee: ResMed Pty Ltd. (ResMed Incorporated)
• Original Assignee: Resmed Limited (ResMed Incorporated)
• Inventors: Farrugia, Steven Paul, Brewer, Gregory Newton, Somaiya, Chinmayee, Colla, Gregory Alan
• Granted Patent: US 9,707,361 B2
• Time in Patent Office: Days
• US Class Current: 128/204.180
• CPC Class Codes: A61M 16/00 Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes stimulating the respiratory movement by mechanical, pneumatic or electrical means, iron lungs combined with gas breathing means A61H31/00
• CPC Class Codes: A61M 16/0069 the speed thereof being controlled by respiratory parameters, e.g. by inhalation
• CPC Class Codes: A61M 16/024 including calculation means, e.g. using a processor
• CPC Class Codes: A61M 16/06 Respiratory or anaesthetic masks
• CPC Class Codes: A61M 16/0605 Means for improving the adaptation of the mask to the patient
• CPC Class Codes: A61M 2016/0021 with a proportional output signal, e.g. from a thermistor
• CPC Class Codes: A61M 2016/0036 in the breathing tube and used in both inspiratory and expiratory phase
• CPC Class Codes: A61M 2205/13 with means for the detection of operative contact with patient, e.g. lip sensor
• CPC Class Codes: A61M 2205/15 Detection of leaks
• CPC Class Codes: A62B 27/00 Methods or devices for testing respiratory or breathing apparatus for high altitudesapparatus for testing gastightness in general G01M

Abstract

CPAP treatment apparatus (10), as one form of positive pressure ventilatory assistance, is disclosed. A turbine/blower (14), operated by a mechanically coupled electrical motor (16), receives air or breathable gas at an inlet (18) thereof, and supplies the breathable gas at a delivery pressure to a delivery tube/hose (20) having connection at the other end thereof with a nose mask (12). A microcontroller (38) has an operational “Mask-Fit” mode. An initial constant pressure level is applied by the blower (14) to the mask (12). If the functional mode is a Manual mode, then the mask-fit test pressure is the current ‘set’ pressure. If the functional mode is the Automatic Titration mode, the mask-fit test pressure is the 95th percentile pressure of the previous session, otherwise it is the base treatment pressure, e.g. 10-12 cm H₂O. This constant pressure is applied for a period of time, typically 1-3 minutes. The microcontroller (38) continuously determines mask leak as the value, f_LEAK, from a flow sensor (32), comparing this to a threshold, and providing the patient with a visual indication of degree of leak. In this way the patient can manipulate the mask to ensure correct fitting as indicated by the appropriate message or indication.

Claims

1-26. -26. (canceled)

27. A method for determining a mask-fit test pressure to be applied to a wearer'"'"'s mask by ventilatory assistance apparatus, the method comprising:

determining a percentile pressure of a previous ventilatory assistance session to be said test pressure.

28. The method of claim 27, wherein said percentile pressure is chosen from the range of the 75^th-95^th percentile pressure.

29. The method of claim 28, further comprising determining a base pressure to be said test pressure if there is no previous percentile pressure available.

30. The method of claim 29, wherein said base pressure is in the range of 10-12 cm H₂O.

31. The method of claim 30, further comprising:

determining that a previous pressure is available if a pressure ventilatory assistance session occurred for greater than a predetermined time interval.

32. The method of claim 31, wherein said predetermined time interval is three hours.

33. A method for assessing correct fitting of a mask delivering ventilatory assistance, provided by ventilatory assistance apparatus, to a wearer of the mask, the method comprising:

determining a percentile pressure of a previous ventilatory assistance session to be applied as a test pressure;

determining leak flow from said mask at the test pressure; and

displaying or otherwise indicating a magnitude of the leak flow as an indication of correct mask fitting.

34. The method of claim 33, wherein said leak flow is quantized to represent a degree of leak.

35. The method of claim 34, further comprising:

comparing said leak flow against a threshold value representing zero degree of leak; and

determining that there is correct mask fitting if the threshold is not exceeded.

36. The method of claim 34, further comprising determining a base pressure to be applied as said test pressure if there is no previous percentile pressure available.

37. The method of claim 36, wherein said percentile pressure is chosen from the range of the 75^th-95^th percentile pressure.

38. The method of claim 37, wherein said base pressure is in the range of 10-12 cm H₂O.

39. The method of claim 37, further comprising determining that a previous pressure is available if a pressure ventilatory assistance session occurred for greater than a predetermined time interval.

40. The method of claim 39, wherein said predetermined time interval is three hours.

41. A method for determining a mask-fit positive test pressure to be applied to a wearer'"'"'s mask by ventilatory assistance apparatus, the method comprising:

determining a percentile pressure of a previous ventilatory assistance session to be said positive test pressure.

42. The method of claim 41, wherein said percentile pressure is chosen from the range of the 75^th-95^th percentile pressure.

43. The method of claim 41, comprising determining a base pressure to be said positive test pressure if there is no previous percentile pressure available.

44. The method claim 43, wherein said base pressure is in the range of 10-12 cm H₂O.

45. The method of claim 41, further comprising determining that a previous pressure is available if a pressure ventilatory assistance session occurred for greater than a predetermined time interval.

46. The method of claim 45, wherein said predetermined time interval is three hours.

47. A method for assessing correct fitting of a mask delivering ventilatory assistance, provided by ventilatory assistance apparatus, to a wearer of the mask, the method comprising:

determining a percentile pressure of a previous ventilatory assistance session to be applied as a positive test pressure;

determining leak flow from said mask at the positive test pressure; and

displaying or otherwise indicating a magnitude of the leak flow as an indication of correct mask fitting.

48. The method of claim 47, wherein said leak flow is quantized to represent a degree of leak.

49. The method of claim 47, further comprising:

comparing said leak flow against a threshold value representing zero degree of leak; and

determining that there is correct mask fitting if the threshold is not exceeded.

50. The method of claim 47, further comprising determining a base pressure to be applied as said positive test pressure if there is no previous percentile pressure available.

51. The method of claim 50, wherein said percentile pressure is chosen from the range of the 75^th-95^th percentile pressure.

52. The method of claim 50, wherein said base pressure is in the range of 10-12 cm H₂O.

53. The method of claim 47, further comprising determining that a previous pressure is available if a pressure ventilatory assistance session occurred for greater than a predetermined time interval.

54. The method of claim 53, wherein said predetermined time interval is three hours.