Pulse Oximetry Is Less Accurate in Patients with Darker Skin Pigmentation

Pulse oximeters estimate the oxygen saturation of blood (SpO₂) noninvasively by passing two wavelengths of light through the body and measuring the change in absorbance. This reading can be affected by the amount of melanin in the skin, and recent data from various hospital settings suggest that readings sometimes might differ from the arterial blood gas (ABG)–derived oxygen saturation (SaO₂).

In a retrospective study from three U.S. hospitals, researchers paired 128,000 SpO₂ measurements with their associated SaO₂ readings in 26,000 adult intensive care unit (ICU) or surgical inpatients. After adjusting for potential confounders, self-identified Black patients were significantly more likely to have occult hypoxemia (defined as SaO₂ <88% des…