A SpO2 measurement system includes at least one light transmitter configured to transmit a first wavelength light and a second wavelength light into tissue of a patient, wherein the second wavelength is shorter than the first wavelength, and a detection device that detects the first wavelength light and the second wavelength light emitted from the tissue of the patient. The SpO2 measurement system operates the at least one light transmitter in a high power mode during a first time period to determine a SpO2 value and a high power DC ratio based on the first wavelength light and the second wavelength light detected during operation in the high power mode. The SpO2 measurement operates the at least one light transmitter in a low power mode during a second time period to determine a low power DC ratio based on the first wavelength light and the second wavelength light detected during operation in the low power mode, and to determine a blood oxygenation status for the patient based on the low power DC ratio.
