A physiological monitoring system including an optical probe configured to output one or more intensity signals representative of at least one physiological characteristic of body tissue, and a signal processing device configured to accept the one or more intensity signals and configured to determine a resulting value indicative of the at least one physiological characteristic, the physiological monitoring system comprising: an optical probe including a light-sensitive detector configured to detect light of at least first and second wavelengths attenuated by body tissue carrying pulsing blood and configured to output one or more intensity signals based on the detected light; and a signal processing device including: a first calculator capable of utilizing a first calculation technique to determine at least a first ratio representative of at least one physiological characteristic of the pulsing blood based on at least one of the one or more intensity signals generated from said detection of said light at said at least first and second wavelengths, a second calculator capable of utilizing a second calculation technique different from the first calculation technique, to determine at least a second ratio representative of the at least one physiological characteristic based on at least one of the one or more intensity signals generated from said detection of said light at said at least first and second wavelengths, and a processing module configured to utilize at least one of the first and second calculators to determine a resulting value indicative of the at least one physiological characteristic. view more

The physiological monitoring system of claim 1, wherein the at least one physiological characteristic comprises a blood constituent level.

The physiological monitoring system of claim 2, wherein the blood constituent level comprises blood oxygen saturation.

The physiological monitoring system of claim 3, wherein the resulting value comprises a ratio.

The physiological monitoring system of claim 3, wherein the resulting value of the blood oxygen saturation is significantly free of an influence of motion induced noise.

The physiological monitoring system of claim 1, wherein said utilization of said at least one of the first and second calculators is based at least in part on a property of the one or more intensity signals.

The physiological monitoring system of claim 15, wherein said property comprises a correlation between at least two of said intensity signals.

The physiological monitoring system of claim 1, wherein the processing module is programmed to evaluate at least one of the one or more intensity signals to obtain an indication of reliability for at least one of the first and second calculation techniques. view more

The physiological monitoring system of claim 1, wherein the processing module is programmed to qualify at least one of the first and second ratios as usable to determine the resulting value.

The physiological monitoring system of claim 1, wherein the first and second calculators are capable of relying on at least partially differing strengths in processing at least one of the one or more intensity signals.

A method of determining a physiological characteristic of pulsing blood, the method comprising: receiving first and second intensity signals from a light-sensitive detector which detects light of at least first and second wavelengths transmitted through body tissue carrying pulsing blood; and utilizing at least one of at least first and second calculation techniques to determine a value indicative of the physiological parameter based upon at least one of the first and second intensity signals, wherein the utilizing comprises qualifying the value for inclusion, depending upon different conditions of the first and second intensity signals, and wherein the first calculation technique is different from the second calculation technique. view more

A physiological monitoring system comprising: a light-sensitive detector which detects light of at least first and second wavelengths attenuated by body tissue carrying pulsing blood and outputs one or more intensity signals based on the detected light, the one or more intensity signals representative of at least one physiological characteristic of the body tissue; and a signal processing device which accepts the one or more intensity signals and determines a resulting value indicative of the at least one physiological characteristic, the signal processing device including: a first calculator capable of utilizing at first calculation technique to determine at least a first value representative of the at least one physiological characteristic of the pulsing blood, a second calculator capable of utilizing a second calculation technique different from the first calculation technique, to determine at least a second value representative of the at least one physiological characteristic, and a processing module which utilizes at least one of the first and second calculators to determine a resulting value indicative of the at least one physiological characteristic, said utilization based at least in part on a property of the one or more intensity signals. view more

The patient monitoring apparatus of claim 53, wherein said property comprises a correlation between at least two of said intensity signals.

A physiological monitor that computes arterial oxygen saturation in tissue material having arterial and venous blood, the physiological monitor comprising:</claim-text> a light emitter which emits light of at least first and second wavelengths; a detector responsive to light from said light emitter which has passed through body tissue having arterial and venous blood, said light detector providing at least first and second intensity signals associated with said at least first and second wavelengths, each of said first and second intensity signals having, during motion of the tissue, at least a first signal portion indicative of arterial blood and a second signal portion indicative of motion induced noise; and a signal processor responsive to the first and second intensity signals to calculate arterial oxygen saturation without significant interference in the calculation from the motion induced noise portion of the first and second intensity signals. view more

The physiological monitor of claim <HIL><BOLD>17</BOLD></HIL>, wherein said motion induced noise is indicative of the attenuation due to venous blood in the tissue during motion.