Diagnosis and treatment of respiratory disorders

1. A method in a processor for detecting a respiratory effort-related arousal in a respiratory airflow signal of a patient, the method comprising:

receiving or calculating in a processor a measure of consistency of inspiratory flow limitation over a plurality of recent breaths from the respiratory airflow signal;

receiving or calculating in the processor a measure of step change in ventilation of the patient indicating a sudden big breath;

. . . and

generating in the processor a maximum measure of inspiratory flow limitation over said plurality of recent breaths,

. . .

controlling, in a controller of a flow generator, adjustment of the respiratory therapy using the parameter, the respiratory therapy produced by the flow generator.

2. The method according to claim 1 , wherein the processor calculates the measure of consistency of inspiratory flow limitation over a plurality of recent breaths from the signal.

3. A method according to claim 2 , wherein calculating the measure of consistency of inspiratory flow limitation comprises calculating a fraction of recent flow limitation measures that exceed a predetermined threshold.

4. The method according to claim 1 wherein the processor calculates the measure of step change in ventilation indicating a sudden big breath.

5. A method according to claim 4 , wherein calculating the measure of step change in ventilation comprises calculating a difference between a current value of a ventilation ratio and a previous value of the ventilation ratio, wherein the ventilation ratio is computed as a mean inspiratory flow rate divided by a measure of current ventilation.

6. A method according to claim 5 , wherein the measure of step change in ventilation is the difference mapped to a range [0, 1].

7. A method according to claim 5 , . . . wherein the mean inspiratory flow rate is computed as an average of inspiratory and expiratory tidal volumes divided by an inspiratory time for a current breath.

8. A method according to claim 1 , further comprising comparing the degree of confidence of occurrence of a respiratory effort-related arousal with a predetermined threshold to provide an indication of whether the patient is currently experiencing a respiratory effort-related arousal.

9. A method according to claim 8 , further comprising calculating a respiratory disturbance index from a number of indications of respiratory effort-related arousals in a predetermined interval.

10. A non-transitory computer-readable memory storage medium having program instructions encoded thereon configured to cause a processor to perform a method of detecting a respiratory effort-related arousal in a respiratory airflow signal of a patient, the method program instructions comprising:

program instructions to generate a measure of consistency of inspiratory flow limitation over a plurality of recent breaths from the respiratory airflow signal;

program instructions to generate a measure of step change in ventilation of the patient indicating a sudden big breath; and

. . .

program instructions to generate a maximum measure of inspiratory flow limitation over said plurality of recent breaths,

. . . control adjustment of the respiratory therapy using the parameter, the respiratory therapy produced by the flow generator.

11. A device for detecting a respiratory effort-related arousal in a respiratory airflow signal of a patient, the device comprising a sensor configured to provide a signal representative of patient respiratory airflow, a processor configured to generate an output indication of a detection of a respiratory effort- related arousal, wherein the processor is configured to:

generate a measure of consistency of inspiratory flow limitation over a plurality of recent breaths from the signal representative of patient respiratory airflow;

generate a measure of step change in ventilation of the patient indicating a sudden big breath;

. . . and

generate a maximum measure of inspiratory flow limitation over said plurality of recent breaths,

. . . controlling adjustment of the respiratory therapy using the parameter, the respiratory therapy produced by the flow generator.