Method and system of detecting faults in a breathing assistance device

• US 20080053441A1
• Filed: 09/01/2006
• Published: 03/06/2008
• Est. Priority Date: 09/01/2006
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Nellcor Puritan Bennett Incorporated (Medtronic Plc)
• Inventors: Fullmer, Michael J., Setzer, Bonny, Gottlib, Kelly S., Snyder, Philip K., Porges, Charles E.
• Granted Patent: US 8,322,339 B2
• Time in Patent Office: Days
• US Class Current: 128/204.23
• CPC Class Codes: A61M 16/0051 with alarm devices
• 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 16/12 by mixing different gases
• CPC Class Codes: A61M 2016/0027 pressure meter
• CPC Class Codes: A61M 2016/0039 in the inspiratory circuit
• CPC Class Codes: A61M 2205/18 with alarm
• CPC Class Codes: A61M 2205/502 User interfaces, e.g. screens or keyboards
• CPC Class Codes: A61M 2205/581 by audible feedback
• CPC Class Codes: A61M 2205/702 automatically during use
• CPC Class Codes: G16H 40/40 for the management of medical equipment or devices, e.g. scheduling maintenance or upgrades

Abstract

A breathing assistance system with functionality for detecting the existence of a fault condition may include a pressure detector, a flow detector and a fault detection system. The pressure detector may take pressure measurements, each measurement comprising a measurement of a gas flow rate in the breathing assistance system. The flow detector may take flow rate measurements, each flow rate measurement comprising a measurement of has flow rate in the breathing assistance system. The fault detection system may process the pressure measurements and/or flow rate measurements to determine the existence of a fault condition associated with the breathing assistance system.

Claims

1. A method of detecting a fault condition in a breathing assistance system, comprising:

receiving a plurality of pressure measurements taken over time, each pressure measurement comprising a measurement of a gas pressure in the breathing assistance system;

determining a filtered pressure error value based at least on the plurality of pressure measurements and a target pressure value, the determination including filtering a plurality of values;

receiving a plurality of flow rate measurements taken over time, each flow rate measurement comprising a measurement of a gas flow rate in the breathing assistance system;

filtering the plurality of flow rate measurements to determine a filtered flow rate value; and

determining the existence of a fault condition based at least on the filtered pressure error value and the filtered flow rate value.

2. A method according to claim 1, wherein at least one of the filtering processes comprises an averaging process.

3. A method according to claim 1, wherein at least one of the filtering processes is performed using a low-pass filter.

4. A method according to claim 3, wherein at least one of the filtering processes is performed using an infinite impulse response (IIR) filter.

5. A method according to claim 1, wherein determining the filtered pressure error value comprises:

filtering the plurality of pressure measurements to determine a filtered pressure measurement; and

comparing the filtered pressure measurement with the target pressure value to determine the filtered pressure error value.

6. A method according to claim 5, wherein filtering the plurality of pressure measurements to determine a filtered pressure measurement comprises averaging the plurality of pressure measurements.

7. A method according to claim 5, wherein filtering the plurality of pressure measurements to determine a filtered pressure measurement comprises using a low-pass filter.

8. A method according to claim 1, wherein determining the filtered pressure error value comprises:

comparing the plurality of pressure measurements with the target pressure value to determine a plurality of pressure error values; and

filtering the plurality of pressure error values to determine the filtered pressure error value.

9. A method according to claim 8, wherein filtering the plurality of pressure error values to determine the filtered pressure error value comprises averaging the plurality of pressure error values.

10. A method according to claim 8, wherein filtering the plurality of pressure error values to determine the filtered pressure error value comprises using a low-pass filter.

11. A method according to claim 1, wherein determining the existence of a fault condition comprises:

comparing the filtered pressure error value with a pressure error threshold value;

comparing the filtered flow rate value with a flow rate threshold value; and

determining the existence of a fault condition based at least on the results of the comparisons.

12. A method according to claim 11, wherein a fault condition is determined if (a) the filtered pressure error value is greater than the pressure error threshold value and (b) the filtered flow rate value is less than the flow rate threshold value.

13. A method according to claim 11, wherein at least one of the flow rate threshold value and the pressure error threshold value can be selected by a user.

14. A method according to claim 11, wherein at least one of the flow rate threshold value and the pressure error threshold value is automatically adjusted over time.

15. A method according to claim 11, wherein determining the existence of a fault condition comprises:

determining number of instances in which (a) the filtered pressure error value is greater than the pressure error threshold value and (b) the filtered flow rate value is less than the flow rate threshold value;

comparing the number of instances to a counter threshold value; and

determining the existence of a fault condition based at least on the results of the comparison.

16. A method according to claim 1, further comprising communicating an alert detectable by a human if a fault condition is determined.

17. A method according to claim 1, further comprising disabling operation a source of pressurized gas flow associated with the breathing assistance system if a fault condition is determined.

18. A method according to claim 17, wherein the source of pressurized gas flow comprises a compressor.

19. A method according to claim 17, wherein the source of pressurized gas flow comprises a blower.

20. A method according to claim 1, wherein the source of pressurized gas flow comprises a wall gas source.

21. A method according to claim 1, wherein determining the existence of a fault condition comprises:

comparing the filtered pressure error value with a pressure error threshold value;

comparing the filtered flow rate value with a first flow rate threshold value; and

determining the existence of a first fault condition if (a) the filtered pressure error value is greater than the pressure error threshold value and (b) the filtered flow rate value is less than the first flow rate threshold value;

comparing the filtered flow rate value to a second flow rate threshold value; and

determining the existence of a second fault condition if (a) the filtered pressure error value is greater than the pressure error threshold value and (b) the filtered flow rate value is greater than the second flow rate threshold value.

22. A method according to claim 21, wherein determining the existence of a fault condition further comprises:

comparing a first counter value threshold to the number of instances in which (a) the filtered pressure error value is greater than the pressure error threshold value and (b) the filtered flow rate value is less than the flow rate threshold value;

determining the existence of the first fault condition based at least on the results of the comparison of the number of instances in which (a) the filtered pressure error value is greater than the pressure error threshold value and (b) the filtered flow rate value is less than the flow rate threshold value;

comparing a second counter value threshold to the number of instances in which (a) the filtered pressure error value is greater than the pressure error threshold value and (b) the filtered flow rate value is greater than the second flow rate threshold value; and

determining the existence of the second fault condition based at least on the results of the comparison of the number of instances in which (a) the filtered pressure error value is greater than the pressure error threshold value and (b) the filtered flow rate value is greater than the second flow rate threshold value.

23. A method according to claim 22, wherein the second fault condition is associated with a decoupling of a patient interface from a patient.

24. A method according to claim 1, wherein determining the existence of a fault condition comprises:

comparing the filtered pressure error value with a pressure error threshold value;

comparing the filtered flow rate value with a first flow rate threshold value;

comparing the filtered flow rate value with a second flow rate threshold value, the second flow rate threshold value being greater than the first flow rate threshold value; and

determining the existence of a fault condition if (a) the filtered pressure error value is greater than the pressure error threshold value and (b) the filtered flow rate value is less than the first flow rate threshold value or greater than the second flow rate threshold value.

25. A method according to claim 1, wherein the breathing assistance system is adapted to provide at least one of continuous positive airway pressure (CPAP) and bi-level CPAP to a patient.

26. A method according to claim 1, wherein the breathing assistance system is adapted to provide ventilation support to a patient.

27. A breathing assistance system, comprising:

a pressure detector operable to take pressure measurements, each pressure measurement comprising a measurement of a gas pressure in the breathing assistance system;

a flow detector operable to take flow rate measurements, each flow rate measurement comprising a measurement of a gas flow rate in the breathing assistance system; and

a fault detection system communicatively coupled to the pressure detector and the flow detector, the fault detection system operable to;

receive a plurality of pressure measurements taken over time from the pressure detector;

determine a filtered pressure error value based at least the plurality of pressure measurements and a target pressure value, the determination including filtering a plurality of values;

receive a plurality of flow rate measurements taken over time, each flow rate measurement comprising a measurement of a gas flow rate in the breathing assistance system;

filter the plurality of flow rate measurements to determine a filtered flow rate value; and

determine the existence of a fault condition based at least on the filtered pressure error value and the filtered flow rate value.

28. A system according to claim 27, wherein the fault detection system includes an averager for determining at least one of the filtered pressure error value and the filtered flow rate value.

29. A system according to claim 27, wherein the fault detection system includes a low-pass filter for determining at least one of the filtered pressure error value and the filtered flow rate value.

30. A system according to claim 29, wherein the low-pass filter comprises an infinite impulse response (IIR) filter.

31. A system according to claim 27, wherein the fault detection system determines the filtered pressure error value at least by:

filtering the plurality of pressure measurements to determine a filtered pressure measurement; and

comparing the filtered pressure measurement with the target pressure value to determine the filtered pressure error value.

32. A system according to claim 31, wherein the fault detection system includes a low-pass filter for filtering the plurality of pressure measurements to determine the filtered pressure measurement.

33. A system according to claim 27, wherein the fault detection system determines the filtered pressure error value at least by:

comparing the plurality of pressure measurements with the target pressure value to determine a plurality of pressure error values; and

filtering the plurality of pressure error values to determine the filtered pressure error value.

34. A system according to claim 33, wherein the fault detection system includes a low-pass filter for filtering the plurality of pressure error values to determine the filtered pressure error value.

35. A system according to claim 27, wherein the fault detection system determines the existence of a fault condition at least by:

comparing the filtered pressure error value with a pressure error threshold value;

comparing the filtered flow rate value with a flow rate threshold value; and

determining the existence of a fault condition based at least on the results of the comparisons.

36. A system according to claim 35, wherein a fault condition is determined if (a) the filtered pressure error value is greater than the pressure error threshold value and (b) the filtered flow rate value is less than the flow rate threshold value.

37. A system according to claim 35, wherein the fault detection system determines the existence of a fault condition at least by:

determining a number of instances in which (a) the filtered pressure error value is greater than the pressure error threshold value and (b) the filtered flow rate value is less than the flow rate threshold value;

comparing the number of instances to a counter value threshold; and

determining the existence of a fault condition based at least on the results of the comparison.

38. A system according to claim 27, wherein the fault detection system is operable to communicate an alert detectable by a human if a fault condition is determined.

39. A system according to claim 27, further comprising:

a source of pressurized gas flow; and

wherein the fault detection system is operable to cause the source of pressurized gas flow to be disabled if a fault condition is determined.

40. A system according to claim 39, wherein the source of pressurized gas flow comprises a compressor.

41. A system according to claim 39, wherein the source of pressurized gas flow comprises a blower.

42. A method according to claim 27, wherein the source of pressurized gas flow comprises a wall gas source.

43. A system according to claim 27, wherein the fault detection system determines the existence of a fault condition at least by:

comparing the filtered pressure error value with a pressure error threshold value;

comparing the filtered flow rate value with a first flow rate threshold value;

determining the existence of a first fault condition if (a) the filtered pressure error value is greater than the pressure error threshold value and (b) the filtered flow rate value is less than the first flow rate threshold value;

comparing the filtered flow rate value to a second flow rate threshold value; and

determining the existence of a second fault condition if (a) the filtered pressure error value is greater than the pressure error threshold value and (b) the filtered flow rate value is greater than the second flow rate threshold value.

44. A system according to claim 43, wherein the fault detection system determines the existence of a fault condition at least by:

comparing a first counter value threshold to the number of instances in which (a) the filtered pressure error value is greater than the pressure error threshold value and (b) the filtered flow rate value is less than the flow rate threshold value;

determining the existence of the first fault condition based at least on the results of the comparison of the number of instances in which (a) the filtered pressure error value is greater than the pressure error threshold value and (b) the filtered flow rate value is less than the flow rate threshold value;

comparing a second counter value threshold to the number of instances in which (a) the filtered pressure error value is greater than the pressure error threshold value and (b) the filtered flow rate value is greater than the second flow rate threshold value; and

determining the existence of the second fault condition based at least on the results of the comparison of the number of instances in which (a) the filtered pressure error value is greater than the pressure error threshold value and (b) the filtered flow rate value is greater than the second flow rate threshold value.

45. A system according to claim 43, wherein the second fault condition is associated with a decoupling of a patient interface from a patient.

46. A system according to claim 27, wherein the fault detection system determines the existence of a fault condition at least by:

comparing the filtered pressure error value with a pressure error threshold value;

comparing the filtered flow rate value with a first flow rate threshold value;

comparing the filtered flow rate value with a second flow rate threshold value, the second flow rate threshold value being greater than the first flow rate threshold value; and

determining the existence of a fault condition if (a) the filtered pressure error value is greater than the pressure error threshold value and (b) the filtered flow rate value is less than the first flow rate threshold value or greater than the second flow rate threshold value.

47. A system according to claim 27, wherein the breathing assistance system is adapted to provide at least one of continuous positive airway pressure (CPAP) and bi-level CPAP to a patient.

48. A system according to claim 27, wherein the breathing assistance system is adapted to provide ventilation support to a patient.

49. A method of detecting a fault condition in a breathing assistance system, comprising:

receiving a plurality of pressure measurements taken over time, each pressure measurement comprising a measurement of a gas pressure in the breathing assistance system;

determining a filtered pressure measurement by processing the plurality of pressure measurements to reduce the effects of outlying pressure measurements;

comparing the filtered pressure measurement with a target pressure value to determine a pressure error value;

determining the existence of a fault condition based at least on the determined pressure error value.

50. A method according to claim 49, further comprising:

receiving a plurality of gas flow measurements taken over time, each gas flow measurement comprising a measurement of a gas flow rate in the breathing assistance system;

determining a filtered flow rate value by processing the plurality of gas flow measurements to reduce the effects of outlying gas flow measurements; and

where determining the existence of a fault condition comprises determining the existence of a fault condition based at least on determined pressure error value and the filtered gas flow value.

51. A method according to claim 50, wherein a fault condition is determined if (a) the determined pressure error value is greater than a pressure error threshold value and (b) the filtered flow rate value is less than a flow rate threshold value.

52. A method according to claim 50, wherein a fault condition is determined if the number of instances in which (a) the determined pressure error value is greater than a pressure error threshold value and (b) the filtered flow rate value is less than a flow rate threshold value, is greater than or equal to a counter value threshold.

53. A method according to claim 49, wherein the filtered pressure measurement is determined using a low-pass filter.

54. A method according to claim 49, further comprising communicating an alert detectable by a human if a fault condition is determined.

55. A method according to claim 49, further comprising disabling operation of a source of pressurized gas flow associated with the breathing assistance system if a fault condition is determined.

56. A method according to claim 55, wherein the source of pressurized gas flow comprises a compressor.

57. A method according to claim 55, wherein the source of pressurized gas flow comprises a blower.

58. A method according to claim 49, wherein the source of pressurized gas flow comprises a wall gas source.

59. A method according to claim 49, wherein the breathing assistance system is adapted to provide at least one of continuous positive airway pressure (CPAP) and bi-level CPAP to a patient.

60. A method according to claim 49, wherein the breathing assistance system is adapted to provide ventilation support to a patient.

61. A method of detecting a fault condition in a breathing assistance system, comprising:

receiving a plurality of pressure measurements taken over time, each pressure measurement comprising a measurement of a gas pressure in the breathing assistance system;

comparing the plurality of pressure measurements with a target pressure value to determine a plurality of pressure error values;

determining a filtered pressure error value by processing the plurality of pressure error values to reduce the effects of outlying pressure error values;

determining the existence of a fault condition based at least on the filtered pressure error value.

62. A method according to claim 61, further comprising:

receiving a plurality of gas flow measurements taken over time, each gas flow measurement comprising a measurement of a gas flow rate in the breathing assistance system;

determining a filtered flow rate value by processing the plurality of gas flow measurements to reduce the effects of outlying gas flow measurements; and

where determining the existence of a fault condition comprises determining the existence of a fault condition based at least on the filtered pressure error value and the filtered gas flow value.

63. A method according to claim 62, wherein a fault condition is determined if (a) the filtered pressure error value is greater than a pressure error threshold value and (b) the filtered flow rate value is less than a flow rate threshold value.

64. A method according to claim 62, wherein a fault condition is determined if the number of instances in which (a) the filtered pressure error value is greater than a pressure error threshold value and (b) the filtered flow rate value is less than a flow rate threshold value, is greater than or equal to a counter value threshold.

65. A method according to claim 61, wherein the filtered pressure measurement is determined using a low-pass filter.

66. A method according to claim 61, further comprising communicating an alert detectable by a human if a fault condition is determined.

67. A method according to claim 61, further comprising disabling operation of a source of pressurized gas flow associated with the breathing assistance system if a fault condition is determined.

68. A method according to claim 61, wherein the source of pressurized gas flow comprises a compressor.

69. A method according to claim 61, wherein the source of pressurized gas flow comprises a blower.

70. A method according to claim 61, wherein the source of pressurized gas flow comprises a wall gas source.

71. A method according to claim 61, wherein the breathing assistance system is adapted to provide at least one of continuous positive airway pressure (CPAP) and bi-level CPAP to a patient.

72. A method according to claim 61, wherein the breathing assistance system is adapted to provide ventilation support to a patient.