US Patent 7899507 Physiological monitor

A patient monitor has multiple sensors adapted to attach to tissue sites of a living subject. The sensors generate sensor signals that are responsive to at least two wavelengths of optical radiation after attenuation by pulsatile blood within the tissue sites. Multiple data channels and associated quality parameters are derived from the sensor signals. A processor is configured to operate on the channels according to the quality parameters so as to provide a robust oxygen status measurement.