System and method for correcting for errors dependent upon spectral characteristics of tissue
Inventors
Mcgonigle, Scott J. • DOVE, Jacob D. • Baker, Jr., Clark R. • Batchelder, Keith A. • Meehan, Christopher J. • VandeRiet, David M. • Prince, Chekema N. • REUSTLE, LINDEN A.
Assignees
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Publication Number
US-12458295-B2
Publication Date
2025-11-04
Expiration Date
Abstract
The present disclosure provides systems and methods for correcting for errors dependent upon spectral characteristics of tissue for a medical device by estimating a spectral characteristic of tissue providing error due to scattering or absorption of emitted light based upon a ratio of measurements for a patient.
Core Innovation
A medical monitoring system determines a physiological parameter based on a sensor signal generated by a sensor that includes a light emitter and a light detector. The system determines one or more input signals based on the sensor signal, where the input signals comprise a ratio of direct current (DC) components. The system determines a correction factor based on the ratio of DC components and adjusts the physiological parameter based on the correction factor.
In the described implementations, the correction factor is derived from tissue spectral characteristics estimated from the red and infrared light used in pulse oximetry/photoplethysmography. The estimation uses ratios of DC components, including variants based on RedDC/IRDC and expressions using SpO2 with the DC-component ratio. Additional embodiments normalize the spectral characteristic correction using a power ratio for the sensor stored in sensor memory, such as an EEPROM.
The adjustment of the physiological parameter is applied to modify the physiological output based on the derived correction factor, including modification of saturation-curve slope/number and use of ratio-of-ratios or calibration/gamma/power ratio parameters. Alternative implementations include determining the correction factor using a neural network classifier, fuzzy/evolutionary/genetic classifier training with additional signals, using temporal averaging and thresholding pigment groups, and supporting reflective-mode estimation where the emitter and detector are on a same side. Additional embodiments describe correction of hemoglobin/other measurements using additional wavelengths.
Claims Coverage
Two independent claims are present: one directed to a medical monitoring system and one directed to a method of operating the medical monitoring system. Both independent claims share the same core inventive approach: deriving a correction factor from a ratio of direct current (DC) components and adjusting the physiological parameter based on that correction factor.
Sensor-derived physiological parameter adjustment using DC-component ratio correction factor
A medical monitoring system determines a physiological parameter based on a sensor signal; determines one or more input signals based on the sensor signal where the input signals comprise a ratio of direct current (DC) components; determines a correction factor based on the ratio of DC components; and adjusts the physiological parameter based on the correction factor.
Processor-based correction factor from sensor DC-component ratio to adjust physiological parameter
A method of operating a medical monitoring system receives, at a processor and from a sensor, a sensor signal indicative of light detected by a detector of the sensor; determines, via the processor, a physiological parameter based on the sensor signal; determines, via the processor, one or more input signals based on the sensor signal where the input signals comprise a ratio of direct current (DC) components; determines, via the processor, a correction factor based on the ratio of DC components; and adjusts, via the processor, the physiological parameter based on the correction factor.
Across both independent claims, the claim coverage centers on computing a correction factor from a ratio of DC components derived from the sensor signal and then adjusting the determined physiological parameter using that correction factor.
Stated Advantages
Not explicitly described in patent.
Documented Applications
Not explicitly described in patent.
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