A flow generator coupled to {TAIL ~ a gas delivery system} delivers {HEAD ~ breathable gas} to the patients airway 
A flow generator coupled to { TAIL ~ a gas delivery system } delivers { HEAD ~ breathable gas } to the patients airway
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH