Method for enhancing pulse oximetry calculations in the presence of correlated artifacts
First Claim
1. In an oximeter, a method for determining a physiological parameter in the presence of correlated artifact, comprising:
- obtaining two digital waveforms, x and y, said waveforms being representative of the absorption of two wavelengths of electromagnetic energy received from a blood-perfused tissue, and wherein each of said waveforms comprises a component corresponding to a plethysmographic waveform and a component corresponding to the correlated artifact;
calculating a plurality of weighted difference waveforms of the form x−
R*y, wherein R is a multiplier, by varying R over a range;
evaluating said plurality of weighted difference waveforms using a shape characteristic of said weighted difference waveform;
identifying a weighted difference waveform most closely representative of said plethysmographic waveform, using said evaluating;
identifying a weighted difference waveform most different from said plethysmographic waveform, using said evaluating;
determining a pleth-based physiological parameter using said waveform most closely representative of said plethysmographic waveform;
determining at least one artifact-based physiological parameter using said waveform most different from said plethysmographic waveform; and
rejecting other possible candidate values for said pleth-based physiological parameter using said artifact-based physiological parameter.
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Abstract
A method for determining a physiological parameter in the presence of correlated artifact, including obtaining two digital waveforms, x and y, the waveforms being representative of the absorption of two wavelengths of electromagnetic energy received from a blood-perfused tissue, and where each of the waveforms has a component corresponding to a plethysmographic waveform and a component corresponding to the correlated artifact; calculating several weighted difference waveforms of the form x−R*y, where R is a multiplier, by varying R over a range; evaluating the several weighted difference waveforms using a shape characteristic of the weighted difference waveform; identifying a weighted difference waveform most closely representative of and one most different from the plethysmographic waveform; determining a pleth-based physiological parameter using the waveform most closely representative of the plethysmographic waveform; determining at least one artifact-based physiological parameter using the waveform most different from the plethysmographic waveform; and rejecting other possible candidate values for the pleth-based physiological parameter using the artifact-based physiological parameter.
44 Citations
14 Claims
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1. In an oximeter, a method for determining a physiological parameter in the presence of correlated artifact, comprising:
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obtaining two digital waveforms, x and y, said waveforms being representative of the absorption of two wavelengths of electromagnetic energy received from a blood-perfused tissue, and wherein each of said waveforms comprises a component corresponding to a plethysmographic waveform and a component corresponding to the correlated artifact; calculating a plurality of weighted difference waveforms of the form x−
R*y, wherein R is a multiplier, by varying R over a range;evaluating said plurality of weighted difference waveforms using a shape characteristic of said weighted difference waveform; identifying a weighted difference waveform most closely representative of said plethysmographic waveform, using said evaluating; identifying a weighted difference waveform most different from said plethysmographic waveform, using said evaluating; determining a pleth-based physiological parameter using said waveform most closely representative of said plethysmographic waveform; determining at least one artifact-based physiological parameter using said waveform most different from said plethysmographic waveform; and rejecting other possible candidate values for said pleth-based physiological parameter using said artifact-based physiological parameter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification