An improved medical gas supply mask adapted to allow insertion of a broncoscope or endoscope into a patients mouth without removing the mask. The masks gas supply portal is located below the mouth instead of directly below the nose. The mask has an attached, typically extendable, tubular bite block that has an outer orifice on the outside of the mask. The surgeon can thus manipulate a scope tube or other instrument into the esophagus or trachea as desired while still providing oxygen to the patient. The mask includes small closed side-ports to receive items like a CO2 monitor tube and the like. Instruments up to approximately 4 cm may be inserted.
