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