Patent ID: RE42843

Claim:
A nasal cannula for use with a constant positive pressure air supply, comprising: first and second nasal inserts for insertion into a patient's nares; said inserts adapted for a sealing relationship with the patient's nares; a left and a right delivery tube, each coupled to both of said nasal inserts, each of said delivery tubes is sufficient to provide all of the air required by the patient; a coupler located remote from said nasal inserts for coupling said cannula to a source of respiration gas; two tubular bleed ports having an internal lumen directly opening into said delivery tubes connecting an interior of the cannula with an exterior of the cannula; each of said bleed ports having a characteristic area expressed as a bleed port diameter called BPD, and separated by a distance called L; each of said tubular bleed ports located beneath each of said nasal inserts such that a first bleed port is located beneath a first insert and a second bleed port is located beneath a second insert, for preferentially intercepting expired gas during exhalation; the sum total of said bleed port diameters, called the Total Bleed Port Diameter (TBPD), have a T BPD/L ratio of between 0.1 and 0.5 such that for the two bleed ports: 0.5>2*BPD/L>0.1