Patent ID: 11918351
Assignee: MEDTRONIC MONITORING, INC.
Field: Medical technology (Instruments)
Classification: CPC A | IPC A

Claim 10:
11. A system comprising:
a medical device comprising:
at least one light source configured to provide incident light to patient tissue;
a first photodetector configured to monitor an emission response at a first emission wavelength, wherein the first emission wavelength is selected to correspond with a maximum of the emission response of oxyhemoglobin;
a second photodetector configured to monitor the emission response at a second emission wavelength, wherein the second emission wavelength is selected to correspond with an isosbestic point of the emission response of oxyhemoglobin and the emission response of de-oxyhemoglobin; and
a third photodetector configured to monitor the emission response at a third emission wavelength, wherein the third emission wavelength is selected to correspond with a maximum of the emission response of de-oxyhemoglobin; and

one or more processors configured to:
receive the emission responses at the first emission wavelength, the second emission wavelength, and the third emission wavelength;
calculate a first ratio based on the received emission responses at the first wavelength and the second wavelength, wherein the first ratio is expressed as a numerator divided by a denominator;
calculate a second ratio based on the received emission responses at the third wavelength and the second wavelength, wherein the second ratio is expressed as a numerator divided by a denominator; and
determine a hemoglobin concentration level based on a combination of the first ratio and the second ratio.