Adaptive cycling for respiratory treatment apparatus

A respiratory treatment apparatus for cycling synchronized respiratory pressure treatment through a patient interface to direct a breathable gas, the respiratory treatment apparatus comprising:

• a flow generator adapted to couple with the patient interface to generate the breathable gas in inspiratory and expiratory pressure cycles through the patient interface;
• a flow sensor to provide a first signal indicative of patient flow through the patient interface;
• a pressure sensor to provide a second signal indicative of pressure at the patient interface;
• a processor, coupled with the flow generator, the pressure sensor and the flow sensor, the processor configured to:
• determine a first flow measure attributable to a patient respiratory muscle effort based on the first signal;
• determine a second flow measure attributable to a flow of the respiratory treatment apparatus;
• determine a pressure measure based on the second signal;
• determine an estimate of the patient respiratory muscle effort as a function of the first flow measure, the second flow measure and the pressure measure;
• and
• derive a cycling control signal as a function of the estimate of respiratory muscle effort.

An automated processing method for cycling a respiratory treatment apparatus that controls a delivery of a synchronized respiratory treatment, the method comprising:

• determining a flow measure with a flow sensor;
• determining a pressure measure with a pressure sensor;
• determining, with a processor, an estimate of muscle effort as a function of the flow measure and pressure measure;
• and
• deriving, with the processor, a cycling control signal as a function of the estimate of muscle effort,
• wherein the determining the estimate is a further function of an estimate of respiratory resistance and compliance,
• wherein the estimate of respiratory resistance and compliance is determined as a function of a portion of patient expiration,
• wherein the estimate is derived from pressure, flow and volume measures taken during the portion of patient expiration,
• wherein the derived estimate is produced by multiple linear regression processing of the pressure, flow and volume measures taken during the portion of patient expiration beginning at patient expiration and ending when approximately ninety percent of a tidal volume has been expired.

A respiratory treatment apparatus for cycling synchronized respiratory pressure treatment through a patient interface to direct a breathable gas, the apparatus comprising:

• a flow generator adapted to couple with the patient interface to generate the breathable gas in inspiratory and expiratory pressure cycles through the patient interface;
• a flow sensor to provide a signal indicative of patient flow through the patient interface;
• a pressure sensor to provide a signal indicative of pressure at the patient interface;
• a processor, coupled with the flow generator, the pressure sensor and the flow sensor, the processor configured to control:
• a determination of a flow measure with the flow sensor;
• a determination of a pressure measure with the pressure sensor;
• a determination of an estimate of muscle effort as a function of the flow measure and pressure measure;
• and
• a derivation of a cycling control signal as a function of the estimate of muscle effort,
• wherein the determination of the estimate is a further function of an estimate of respiratory resistance and compliance,
• wherein the estimate of respiratory resistance and compliance is determined as a function of a portion of patient expiration,
• wherein the estimate is derived from pressure, flow and volume measures taken during the portion of patient expiration,
• wherein the derived estimate is produced by multiple linear regression processing of the pressure, flow and volume measures taken during the portion of patient expiration beginning at patient expiration and ending when approximately ninety percent of a tidal volume has been expired.