Characterizing the influence of skin pigmentation on pulse oximetry

SignificancePulse oximeters are frequently used in healthcare settings to noninvasively estimate blood oxygen levels in patients, in turn influencing clinical decision-making. However, numerous studies have found pulse oximeters consistently overestimate oxygen levels in patients of color, with this overestimation increasing as oxygen levels decline. Although some reports postulate skin pigmentation may be the source of bias, to our knowledge, the precise impact of skin pigmentation on pulse oximetry has not been elucidated.AimOur objective is to experimentally characterize the impact of skin pigmentation on pulse oximeters across a broad range of oxygen saturations and determine whether skin pigmentation can explain the observed pulse oximeter bias in patients of color.ResultsUsing a live porcine model, we experimentally demonstrate the impact of skin pigmentation on pulse oximeter calculation. In particular, we show that skin pigmentation attenuates the sensitivity of red-light absorption to changes in oxygen saturation and show that the pulse oximeter output is consequently attenuated in pigmented skin.ConclusionThe systematic animal experiments confirm the confounding impact of skin pigmentation on intermediate calculations of pulse oximetry, and validate existing clinical observations of pulse oximeter bias in patients of color.