Respiration sensing

A device comprising:

• a sensor securable to a patient to provide a sensor signal, the sensor to sense changes in acceleration indicative of respiration of the patient;
• and
• a control portion configured to:
• determine a midpoint of each respiratory phase of the patient based on the sensor signal;
• identify each expiratory phase or each inspiratory phase of the patient based on the sensor signal;
• and
• predict a midpoint of a future inspiratory phase based on previous midpoints of each respiratory phase.