An oxygen delivery and gas sensing nasal cannula system, comprising a main
prong assembly and a pair of nasal prongs. There is also provided a pair
of oxygen conduit tubes and a main oxygen delivery tube. There is also
provided an adjustment sleeve to adjust the fit of the cannula system on a
patient's head. There is also included a gas sampling, a gas sampling
conduit end piece and a flared main oxygen delivery tube end piece to be
receivably coupled to an oxygen supply.