Apparatus and methods for ventilatory treatment

A method for treating a respiratory disorder, the method comprising:

• computing a measure of M-shaped inspiratory flow limitation,
• compute a proportion of maximum increase in expiratory positive airway pressure (EPAP) as a function of the measure of the M-shaped inspiratory flow limitation,
• adjust the proportion of maximum increase in EPAP dependent on a ratio of breathwise ventilation to typical recent ventilation,
• increasing an EPAP value according to the adjusted proportion of maximum increase in EPAP;
• and
• controlling, with a controller and a therapy device, delivery of pressure based on the EPAP value.

A non-transitory computer readable storage medium comprising stored processor control instructions configured to control a processor of a respiratory apparatus for treating a respiratory disorder, wherein the stored processor control instructions, when executed by the processor, cause the processor to:

• compute a measure of M-shaped inspiratory flow limitation,
• compute a proportion of maximum increase in expiratory positive airway pressure (EPAP) as a function of the measure of the M-shaped inspiratory flow limitation,
• adjust the proportion of maximum increase in EPAP dependent on a ratio of breathwise ventilation to typical recent ventilation,
• increase an EPAP value according to the adjusted proportion of maximum increase in EPAP, and
• control delivery of pressure based on the EPAP value.

An apparatus for treating a respiratory disorder, the apparatus comprising a controller of a therapy device, the apparatus being configured to:

• compute a measure of M-shaped inspiratory flow limitation,
• compute a plurality of separate pressure components for an increase in expiratory positive airway pressure (EPAP), wherein a pressure component of the computed plurality of separate pressure components is a proportion of a maximum increase in expiratory positive airway pressure (EPAP) that is due to the measure of M-shaped inspiratory flow limitation,
• adjust the pressure component that is the proportion of maximum increase in EPAP, dependent on a ratio of breathwise ventilation to typical recent ventilation, and
• increase an EPAP value with the pressure component that is the adjusted proportion of maximum increase in EPAP
• control, with the controller and the therapy device, delivery of pressure based on the EPAP value.