The controller detects {HEAD ~ transitions} between inspiration and expiration via a flow signal to discriminate between {TAIL ~ the respiratory phases} of the patient 
The controller detects { HEAD ~ transitions } between inspiration and expiration via a flow signal to discriminate between { TAIL ~ the respiratory phases } of the patient
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH