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Are Muscle Oxygen Sensors the Next Great Fitness Wearable? - Outside Online

The technology used to measure muscle oxygen is called near-infrared spectroscopy, or NIRS. By shining light through your skin and measuring what’s reflected, NIRS can assess what percentage of hemoglobin and myoglobin molecules in the muscle and tissue underneath are carrying oxygen. If that number is increasing toward 100 percent, it means the oxygen supply exceeds the muscle’s demands; if it’s drifting down toward zero, demand is outstripping supply. Pedaling as hard as you can for five minutes might get your quads down below 20 percent, and elite athletes can push even lower. (The basic idea is similar to pulse oximeters, but those measure oxygen in your bloodstream rather than in a specific muscle.)

Racial Bias in Pulse Oximetry Measurement | NEJM

Thus, in two large cohorts, Black patients had nearly three times the frequency of occult hypoxemia that was not detected by pulse oximetry as White patients. Given the widespread use of pulse oximetry for medical decision making, these findings have some major implications, especially during the current coronavirus disease 2019 (Covid-19) pandemic. Our results suggest that reliance on pulse oximetry to triage patients and adjust supplemental oxygen levels may place Black patients at increased risk for hypoxemia. It is important to note that not all Black patients who had a pulse oximetry value of 92 to 96% had occult hypoxemia. However, the variation in risk according to race necessitates the integration of pulse oximetry with other clinical and patient-reported data.

The Accuracy of Noninvasive Peripheral Pulse Oximetry After Palliative Cardiac Surgery in Patients With Cyanotic Congenital Heart Disease - Gemma E. Scrimgeour, Michael J. Griksaitis, John V. Pappachan, Andrew J. Baldock, 2017

SpO2 (Masimo SET LNCS Neo pulse oximeter) overestimated oxyhemoglobin saturation in 82% of measurements (mean 4.6% ± 6.6%). There was a strong negative correlation between mean bias and SaO2 (r = −.96, P = .002, 95% confidence interval: −0.99 to −0.68).