Autotitrating method and apparatus

• US 20060027234A1
• Filed: 08/05/2005
• Published: 02/09/2006
• Est. Priority Date: 08/06/2004
• Status: Active Grant

• Current Assignee: Fisher & Paykel Healthcare Limited
• Original Assignee: Fisher & Paykel Healthcare Limited
• Inventors: Whiting, David Robin, Gradon, Lewis George, Anderson, Fiona Elizabeth, Gerred, Andrew Gordon, Smith, Gregory Martyn
• Granted Patent: US 7,882,834 B2
• Time in Patent Office: Days
• US Class Current: 128/204.210
• CPC Class Codes: A61M 16/0003 Accessories therefor, e.g. sensors, vibrators, negative pressure
• 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 16/10 Preparation of respiratory gases or vapours
• CPC Class Codes: A61M 16/109 the humidifying liquid or the beneficial agent
• CPC Class Codes: A61M 16/16 Devices to humidify the respiration air A61M16/1045 takes precedence
• CPC Class Codes: A61M 2016/0021 with a proportional output signal, e.g. from a thermistor
• CPC Class Codes: A61M 2016/003 with a flowmeter
• CPC Class Codes: A61M 2016/0033 electrical
• CPC Class Codes: A61M 2205/3334 Measuring or controlling the flow rate
• CPC Class Codes: A61M 2205/3372 Temperature compensation

Abstract

An apparatus and method of controlling the delivery of therapeutic gas delivered to a patient undergoing positive airway pressure therapy is described. The method includes providing a flow of gas to a patient'"'"'s airway at a pressure, obtaining information from the range of 0 to 25 Hz of the frequency domain of the flow, and adjusting the pressure based on the information. The apparatus includes a blower for providing a flow of gas to a patient'"'"'s airway at a pressure, a sensor to measure a characteristic of the flow, a controller to obtain information from the range of 0 to 25 Hz of the frequency domain of the characteristic, and a pressure regulator for adjusting the pressure based on the information.

Claims

1. A method of controlling positive airway pressure therapy, comprising the steps of:

providing a flow of gas to a patient'"'"'s airway at a pressure;

obtaining information from a frequency range of 0 to 25 Hz in a frequency domain of said flow; and

adjusting said pressure based on said information.

2. The method of claim 1, wherein said information comprises at least one information-bearing value generated from said frequency domain information.

3. The method of claim 2, wherein said adjusting step further comprises comparing said at least one information-bearing value to a threshold.

4. The method of claim 2, wherein said adjusting step further comprises comparing said at least one information-bearing value to one of a plurality of thresholds.

5. The method of claim 2, further comprising the steps of calculating a period of a breath of a patient and calculating an inspiratory portion of said period, and wherein said adjusting step comprises comparing said at least one information-bearing value to one of a plurality of thresholds, said one of a plurality of thresholds being selected according to a ratio of said inspiratory portion to said period.

6. The method of claim 2, wherein said information comprises a discrete energy spectrum and said information-bearing value comprises at least an energy in a first harmonic of said discrete energy spectrum and an energy in a second harmonic of said discrete energy spectrum.

7. The method of claim 6, wherein said adjusting step further comprises comparing said at least one information-bearing value to a threshold.

8. The method of claim 6, wherein said adjusting step further comprises comparing said at least one information-bearing value to one of a plurality of thresholds.

9. The method of claim 6, further comprising the steps of calculating a period of a breath of a patient and calculating an inspiratory portion of said period, and wherein said adjusting step comprises comparing said at least one information-bearing value to one of a plurality of thresholds, said one of a plurality of thresholds being selected according to a ratio of said inspiratory portion to said period.

10. The method of claim 2, wherein said information comprises a discrete energy spectrum and said at least one information-bearing value comprises an energy in a first harmonic of said discrete energy spectrum, an energy in a second harmonic of said discrete energy spectrum, a sum of energies of said first harmonic through a thirteenth harmonic of said discrete energy spectrum, and a sum of energies of a fifth harmonic through said thirteenth harmonic of said discrete energy spectrum.

11. The method of claim 10 wherein said adjusting step further comprises comparing said at least one information-bearing value to a threshold.

12. The method of claim 10, wherein said adjusting step further comprises comparing said at least one information-bearing value to one of a plurality of thresholds.

13. The method of claim 10, further comprising the steps of calculating a period of a breath of a patient and calculating an inspiratory portion of said period, and wherein said adjusting step comprises comparing said at least one information-bearing value to one of a plurality of thresholds, said one of a plurality of thresholds being selected according to a ratio of said inspiratory portion to said period.

14. The method of claim 2, wherein said at least one information-bearing value comprises a plurality of information-bearing values.

15. The method of claim 14, wherein said adjusting step further comprises comparing each of said plurality of information-bearing values to a threshold.

16. The method of claim 14, wherein said adjusting step further comprises comparing each of said plurality of information-bearing values to one of a plurality of thresholds.

17. The method of claim 14, further comprising the steps of calculating a period of a breath of a patient and calculating an inspiratory portion of said period, and wherein said adjusting step comprises comparing each of said plurality of information-bearing values to one of a plurality of thresholds, said one of a plurality of thresholds being selected according to a ratio of said inspiratory portion to said period.

18. The method of claim 14, wherein said information comprises a discrete energy spectrum and said plurality of information-bearing values comprises at least an energy in a first harmonic of said discrete energy spectrum and an energy in a second harmonic of said discrete energy spectrum.

19. The method of claim 18, wherein said adjusting step further comprises comparing each of said plurality of information-bearing values to a threshold.

20. The method of claim 18, wherein said adjusting step further comprises comparing each of said plurality of information-bearing values to one of a plurality of thresholds.

21. The method of claim 18, further comprising the steps of calculating a period of a breath of a patient and calculating an inspiratory portion of said period, and wherein said adjusting step comprises comparing each of said plurality of information-bearing values to one of a plurality of thresholds, said one of a plurality of thresholds being selected according to a ratio of said inspiratory portion to said period.

22. The method of claim 14, wherein said information comprises a discrete energy spectrum and said plurality of information-bearing values comprises an energy in a first harmonic of said discrete energy spectrum, an energy in a second harmonic of said discrete energy spectrum, a sum of energies of said first harmonic through a thirteenth harmonic of said discrete energy spectrum, and a sum of energies of a fifth harmonic through said thirteenth harmonic of said discrete energy spectrum.

23. The method of claim 22 wherein said adjusting step further comprises comparing each of said plurality of information-bearing values to a threshold.

24. The method of claim 22, wherein said adjusting step further comprises comparing each of said plurality of information-bearing values to one of a plurality of thresholds.

25. The method of claim 22, further comprising the steps of calculating a period of a breath of a patient and calculating an inspiratory portion of said period, and wherein said adjusting step comprises comparing each of said plurality of information-bearing values to one of a plurality of thresholds, said one of a plurality of thresholds being selected according to a ratio of said inspiratory portion to said period.

26. An apparatus for controlling positive airway pressure therapy, comprising:

a blower for providing a flow of gas to a patient at a pressure;

a sensor to measure a characteristic of said flow;

a controller to obtain information from a frequency range of 0 to 25 Hz in a frequency domain of said characteristic; and

a pressure regulator controlled by said controller for adjusting said pressure based on said information.

27. The apparatus of claim 26, wherein said information comprises at least one information-bearing value generated from said frequency domain information.

28. The apparatus of claim 27, wherein said controller further compares said at least one information-bearing value to a threshold.

29. The apparatus of claim 27, wherein said controller further compares said at least one information-bearing value to one of a plurality of thresholds.

30. The apparatus of claim 27, wherein said controller further calculates a period of a breath of a patient and an inspiratory portion of said period, and further compares said at least one information-bearing value to one of a plurality of thresholds, said one of a plurality of thresholds being selected according to a ratio of said inspiratory portion to said period.

31. The apparatus of claim 26, wherein said information comprises a discrete energy spectrum and said at least one information-bearing value comprises at least an energy in a first harmonic of said discrete energy spectrum and an energy in a second harmonic of said discrete energy spectrum.

32. The apparatus of claim 31, wherein said controller further compares said at least one information-bearing value to a threshold.

33. The apparatus of claim 31, wherein said controller further compares said at least one information-bearing value to one of a plurality of thresholds.

34. The apparatus of claim 31, wherein said controller further calculates a period of a breath of a patient and an inspiratory portion of said period, and further compares said at least one information-bearing value to one of a plurality of thresholds, said one of a plurality of thresholds being selected according to a ratio of said inspiratory portion to said period.

35. The apparatus of claim 26, wherein said information comprises a discrete energy spectrum and said at least one information-bearing value comprises an energy in a first harmonic of said discrete energy spectrum, an energy in a second harmonic of said discrete energy spectrum, a sum of energies of said first harmonic through a thirteenth harmonic of said discrete energy spectrum, and a sum of energies of a fifth harmonic through said thirteenth harmonic of said discrete energy spectrum.

36. The apparatus of claim 35, wherein said controller further compares said at least one information-bearing value to a threshold.

37. The apparatus of claim 35, wherein said controller further compares said at least one information-bearing value to one of a plurality of thresholds.

38. The apparatus of claim 35, wherein said controller further calculates a period of a breath of a patient and an inspiratory portion of said period, and further compares said at least one information-bearing value to one of a plurality of thresholds, said one of a plurality of thresholds being selected according to a ratio of said inspiratory portion to said period.

39. The apparatus of claim 26, wherein said at least one information-bearing value comprises a plurality of information-bearing values.

40. The apparatus of claim 39, wherein said controller further compares each of said plurality of information-bearing values to a threshold.

41. The apparatus of claim 39, wherein said controller further compares said plurality of information-bearing values to one of a plurality of thresholds.

42. The apparatus of claim 39, wherein said controller further calculates a period of a breath of a patient and an inspiratory portion of said period, and further compares said plurality of information-bearing values to one of a plurality of thresholds, said one of a plurality of thresholds being selected according to a ratio of said inspiratory portion to said period.

43. The apparatus of claim 39, wherein said information comprises a discrete energy spectrum and said plurality of information-bearing values comprises at least an energy in a first harmonic of said discrete energy spectrum and an energy in a second harmonic of said discrete energy spectrum.

44. The apparatus of claim 43, wherein said controller further compares each of said plurality of information-bearing values to a threshold.

45. The apparatus of claim 43, wherein said controller further compares each of said plurality of information-bearing values to one of a plurality of thresholds.

46. The apparatus of claim 43, wherein said controller further calculates a period of a breath of a patient and an inspiratory portion of said period, and further compares each of said plurality of information-bearing values to one of a plurality of thresholds, said one of a plurality of thresholds being selected according to a ratio of said inspiratory portion to said period.

47. The apparatus of claim 39, wherein said information comprises a discrete energy spectrum and said plurality of information-bearing values comprises an energy in a first harmonic of said discrete energy spectrum, an energy in a second harmonic of said discrete energy spectrum, a sum of energies of said first harmonic through a thirteenth harmonic of said discrete energy spectrum, and a sum of energies of a fifth harmonic through said thirteenth harmonic of said discrete energy spectrum.

48. The apparatus of claim 47, wherein said controller further compares each of said plurality of information-bearing values to a threshold.

49. The apparatus of claim 47, wherein said controller further compares each of said plurality of information-bearing values to one of a plurality of thresholds.

50. The apparatus of claim 47, wherein said controller further calculates a period of a breath of a patient and an inspiratory portion of said period, and further compares each of said plurality of information-bearing values to one of a plurality of thresholds, said one of a plurality of thresholds being selected according to a ratio of said inspiratory portion to said period.