An oxygen mask for delivering oxygen to a patient comprises a mask body adapted to substantially cover a patients nose and mouth and having a peripheral edge adapted to substantially seal against the patients face and forming a compartment, an oxygen inflow port defined in the mask body, an L-shaped connector coupled to the oxygen inflow port, an oxygen conduit coupled to the L-shaped connector and having access to the compartment in the mask body via the oxygen inflow port, the oxygen conduit adapted to conduct oxygen flow from an oxygen supply to the compartment in the mask body, and an expired gas sampling tube coupled to the mask body and having access to the compartment in the mask body, the expired gas sampling tube having a perforated segment with a plurality of perforations attached to an interior surface of the mask body, the expired gas sampling tube adapted to couple to an instrument operable to monitor the expired gases.
