Skin Pigmentation and Accuracy of Pulse Oximetry Values

First introduced in the 1970s, pulse oximetry has been a mainstay in patient monitoring and respiratory management for more than 50 years.¹  Using sensors placed on the fingertip, earlobe, or forehead, this simple, low-cost noninvasive technology uses the principle of photoplethysmography. With photoplethysmography, the intensity of light traveling through tissue is modulated by the absorption of light by pulsatile blood.²  Oxygenated and deoxygenated hemoglobin absorb different amounts of certain wavelengths of light. Specifically, oxygenated hemoglobin absorbs more infrared light whereas deoxygenated hemoglobin absorbs more red light. Pulse oximeters calculate oxygen saturation values by comparing the ratio of red to infrared light absorption in arterial blood against manufacturers’ empirically derived calibration curves mapped to known arterial oxygen saturation (Sao₂) values.^1,3 

While the COVID-19 pandemic broadened the use of pulse oximetry to assess blood oxygenation rapidly in hospital and home settings, the pandemic also further...