{HEAD ~ A nitrous oxide} and {TAIL ~ oxygen supply}, vacuum source, a breather bag, and a nasal delivery interface system are fluidly connected to the fluid control system and a patient 
{ HEAD ~ A nitrous oxide } and { TAIL ~ oxygen supply } , vacuum source , a breather bag , and a nasal delivery interface system are fluidly connected to the fluid control system and a patient
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH