Carbon dioxide-based bi-level CPAP control

• US 20050279358A1
• Filed: 08/18/2005
• Published: 12/22/2005
• Est. Priority Date: 09/28/2000
• Status: Active Grant

• Current Assignee: Invacare Corporation
• Original Assignee: Invacare Corporation
• Inventors: Richey, Joseph B. II
• Granted Patent: US 8,640,701 B2
• Time in Patent Office: Days
• US Class Current: 128/204.230
• 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 16/085 Gas sampling
• CPC Class Codes: A61M 16/161 with means for measuring the humidity
• CPC Class Codes: A61M 2205/3368 Temperature
• CPC Class Codes: A61M 2230/432 partial CO2 pressure (P-CO2)

Abstract

A system and method of providing bi-level CPAP therapy is provided that incorporates an infrared carbon-dioxide sensor to determine whether a patient is inhaling or exhaling. Patient exhalation causes the infrared light to be absorbed, while patient inhalation reduces the presence of carbon-dioxide causes little or no absorption of carbon-dioxide The level of carbon-dioxide in an associated patient breathing interface is monitored for thresholds that trigger higher CPAP pressure upon inhalation and lower CPAP pressure upon exhalation.

Claims

1-21. -21. (canceled)

22. A system for administering a breathing gas to a patient breathing interface comprising:

(a) a blower for providing positive pressure breathing gas;

(b) a controller in circuit communication with the blower;

(c) an infrared light emitter and detector in circuit communication with the controller for detecting the level of carbon-dioxide associated with the patient breathing interface; and

(d) logic for increasing and decreasing the pressure of the positive pressure breathing gas based on the level of carbon-dioxide detected to maintain open the airway of a patient.

23. The system of claim 22 wherein the logic for increasing and decreasing the pressure of the positive pressure breathing gas based on the level of carbon-dioxide associated with the patient breathing interface comprises logic for comparing the level of carbon-dioxide associated with the patient breathing interface to a threshold parameter.

24. The system of claim 22 further comprising a timer having a variable off time period and predetermined on time period.

25. The system of claim 22 further comprising optical fibers coupled to the infrared emitter and detector.

26. The system of claim 22 wherein the infrared emitter and detector are located within a housing accommodating the controller.

27. The system of claim 22 wherein the infrared emitter and detector are located within the patent breathing interface.

28. The system of claim 22 wherein the infrared emitter and detector are located proximate to a vent of the patient breathing interface.

29. A system for administering a breathing gas to a patient via a patient breathing interface comprising:

(a) a subsystem capable of providing variable positive pressure breathing gas to the patient breathing interface;

(b) a controller in circuit communication with the subsystem;

(c) a carbon dioxide detector in communication with the patient breathing interface for detecting whether the patient is inhaling or exhaling; and

(d) logic in communication with the carbon dioxide detector and the subsystem to cause the subsystem to provide a first pressure of the positive pressure breathing gas if the patient is inhaling and to provide a second pressure of the positive pressure breathing gas if the patient is exhaling.

30. The system of claim 29, wherein the subsystem comprises a blower.

31. The system of claim 30, wherein the subsystem comprises a driver capable of driving the blower through a range of variable speeds.

32. The system of claim 30, wherein the subsystem comprises an adjustable valve responsive to the logic.

33. The system of claim 29, wherein the detector comprises an infrared light emitter and detector.

34. The system of claim 29, wherein the logic is capable of comparing a level of carbon dioxide detected in the patient breathing interface by the detector to a threshold parameter.

35. The system of claim 34, further comprising at least one input device in communication with the logic to enable input of a desired value for the threshold parameter.

36. The system of claim 29, further comprising an input device in communication with the logic to enable input of a desired value for at least one of the first pressure and the second pressure.

37. The system of claim 29, further comprising a device in communication with the logic and capable of causing the subsystem to provide the first pressure of the positive pressure breathing gas for a fixed time period.

38. The system of claim 37, wherein the device comprises a timer.

39. A system for administering breathing gas to a patient breathing interface, comprising:

(a) a variable speed blower providing variable positive pressure breathing gas to the patient breathing interface;

(b) a controller in circuit communication with the blower;

(c) an infrared light emitter and detector in communication with the patient breathing interface for detecting the level of carbon-dioxide associated with the patient breathing interface to determine whether the patient is inhaling or exhaling;

(d) logic in communication with the infrared light detector and the variable speed blower to cause the variable speed blower to provide a first pressure of the positive pressure breathing gas if the patient is inhaling and to provide a second pressure of the positive pressure breathing gas if the patient is exhaling; and

(e) at least one input device in communication with the logic to enable input of a desired value for a threshold parameter and at least one of the first pressure and the second pressure;

wherein the logic is capable of comparing a level of carbon dioxide detected in the patient breathing interface by the detector to the threshold parameter.

40. A system for administering a breathing gas to a patient via a patient breathing interface comprising;

(a) means for providing variable positive pressure breathing gas to the patient breathing interface;

(b) means for determining whether the patient is inhaling or exhaling based on detection of carbon dioxide in the patient breathing interface; and

(c) means for maintaining open the airway of the patient by causing a first pressure of the positive pressure breathing gas to be provided to the patient breathing interface if the patient is inhaling and for causing a second pressure of the positive pressure breathing gas to be provided to the patient breathing interface if the patient is exhaling.

41. The system of claim 40, further comprising means for detecting carbon dioxide.