Method and apparatus for providing variable positive airway pressure

1. A system for delivering a flow of gas to an airway of a patient, the system comprising:

a gas flow generating system that generates a flow of gas;

a patient circuit coupled to the gas flow generating system and adapted to communicate the flow of gas to an airway of a patient;

a sensor associated with the gas flow generating system or the patient circuit and adapted to measure a characteristic associated with the flow of gas within the patient circuit and to transmit a flow signal indicative thereof;

target value determining means for monitoring an effectiveness of the system in treating Cheyne-Stokes respiration of such a patient and for setting a target value based on the monitored effectiveness;

CSR monitoring means for determining whether such a patient's respiratory activity is indicative of Cheyne-Stokes respiration by comparing the characteristic associated with the flow of gas with the target value; and

controlling means for controlling the gas flow generating system so as to cause the gas to be delivered at a sufficient pressure during at least a portion of a breathing cycle to treat Cheyne-Stokes respiration based on an output of the CRS monitoring means.

2. The system of claim 1 , wherein the gas flow generating system includes:

a pressure generator adapted to generate the flow of gas; and

a pressure control valve associated with the pressure generator or the patient circuit to control a pressure of the flow of gas delivered to a patient by the patient circuit.

3. The system of claim 1 , wherein the target monitoring means sets a value for a target peak flow Q peak(target) as the target value based on whether such a patient's respiratory activity is indicative of Cheyne-Stokes respiration, wherein the CSR monitoring means compares an inspiratory peak flow Q peak(current) to the target peak flow Q peak(target) , and wherein the controlling means causes the gas flow generating system to adjust a pressure of the flow of gas based on the comparison between the inspiratory peak flow Q peak(current) and the target peak flow Q peak(target) .

4. The system of claim 3 , wherein the CSR monitoring means adjusts the value of the target peak flow Q peak(target) , an expiratory positive airway pressure, or both, responsive to a determination that the delivering of pressurized gas in the treatment is not effectively treating Cheyne-Stokes respiration.

5. The system of claim 1 , wherein the controlling means detects I/E transitions between an inspiratory phase and an expiratory phase of a respiratory cycle, and causes the gas flow generating system to deliver a machine breath responsive to a failure to detect a patient initiated breath between within a predetermined period of time.

6. The system of claim 1 , wherein the CSR monitoring means determines magnitudes and times of inspiratory peaks flows and comparing these to a Cheyne-Stokes respiration pattern.

7. The system of claim 1 , wherein the target value determining means, the CSR monitoring means, the controlling means, or a combination thereof are implemented on a common processing system.

8. A method for delivering pressurized gas to an airway of a patient, the method comprising the steps of:

delivering a flow of gas to the airway of the patient from a source of gas via a patient circuit;

sensing a characteristic associated with a flow of gas within the patient circuit and outputting a flow signal;

monitoring an effectiveness of the system in treating Cheyne-Stokes respiration of such a patient and setting a target value based on the monitored effectiveness;

determining whether such a patient's respiratory activity is indicative of Cheyne-Stokes respiration by comparing the characteristic associated with the flow of gas with the target value; and

controlling the delivery of gas so as to cause the flow of gas to be delivered at a sufficient pressure during at least a portion of a breathing cycle to treat Cheyne-Stokes respiration based on a result of the determining step.

9. The method of claim 8 , wherein delivering a flow of gas includes generating a flow of gas via a pressure generator and controlling a pressure of the flow of gas via (1) a pressure control valve associated with the pressure generator or the patient circuit, (2) controlling an operating speed of the pressure generator, or (3) a combination of both (1) and (2).

10. The method of claim 8 , wherein sensing a characteristic associated with a flow of gas within the patient circuit includes determining an inspiratory peak flow Q peak(current) , wherein monitoring the effectiveness of the system includes determining a target peak flow Q peak(target) as the target value, wherein determining whether such a patient's respiratory activity is indicative of Cheyne-Stokes respiration includes comparing the inspiratory peak flow Q peak(current) to the target peak flow Q peak(target) , and wherein controlling the delivery of gas includes adjusting a pressure of the flow of gas based on the comparison between the inspiratory peak flow Q peak(current) and the target peak flow Q peak(target) .

11. The method of claim 10 , wherein monitoring an effectiveness of the system in treating Cheyne-Stokes respiration includes adjusting the target peak flow Q peak(target) , an expiratory positive airway pressure, or both, responsive to a determination that the delivering of pressurized gas in the treatment is not effectively treating Cheyne-Stokes respiration.

12. The method of claim 8 , further comprising:

detecting I/E transitions between an inspiratory phase and an expiratory phase of a respiratory cycle; and

delivering a machine generated breath to a patient responsive to a failure to detect a patient initiated breath between within a predetermined period of time.

13. The method of claim 8 , wherein monitoring whether such a patient's respiratory activity is indicative of Cheyne-Stokes respiration includes determining magnitudes and times of inspiratory peaks flows and comparing these to a Cheyne-Stokes respiration pattern.