The present invention relates to novel lip/cheek probes for detection of
pulse-based differences in light absorbence across the vascularized
tissue of a lip or cheek of a patient. These probes are fabricated to
provide signals to estimate arterial oxygen saturation, and/or to obtain
other photoplethysmographic data. The present invention also relates to a
combined probe/cannula. The present invention also relates to other
devices that combine a pulse oximeter probe with a device supplying
oxygen or other oxygen-containing gas to a person in need thereof, and to
sampling means for exhaled carbon dioxide in combination with the novel
lip/cheek probes. In certain embodiments, an additional limitation of a
control means to adjust the flow rate of such gas is provided, where such
control is directed by the blood oxygen saturation data obtained from the
pulse oximeter probe.