The Big Consequences of Small Discrepancies: Why Racial Differences in Pulse Oximetry Errors Matter

• Authors: Andre Holder, Emory University; An-Kwok Ian Wong, Duke University
• Journal Title: CRITICAL CARE MEDICINE
• Volume: Volume 50, Number 2
• Publisher: LIPPINCOTT WILLIAMS & WILKINS | 2022-02-01, Pages 335-337
• Type of Work: Article | Post-print: After Peer Review
• Publisher DOI: http://doi.org/10.1097/CCM.0000000000005447
• Subjects: Biology, Biostatistics
• Keywords: Science & Technology; Life Sciences & Biomedicine; Critical Care Medicine; General & Internal Medicine; information bias; measurement bias; occult hypoxemia; pulse oximetry; racial disparities; SKIN PIGMENTATION; ACCURACY; RELIABILITY; BIAS

Abstract

The COVID-19 pandemic has highlighted the need for reliable, point-of-care blood oxygen assessment among hospitalized patients at high risk of acute hypoxemic respiratory failure. However, biases in pulse oximetry measurement among racial minorities has been a concern for at least three decades. (1) The principles of pulse oximetry rely on differential light absorption of oxyhemoglobin and deoxyhemoglobin in capillary blood to indirectly estimate arterial oxygen saturation (SaO2). (2) However, skin pigmentation can impact light absorption independent of the proportion of deoxyhemoglobin, which could lead to erroneous pulse-oximetry-derived oxygen saturation (SpO2) values (measurement bias) in darker-skinned persons. (3) Jubran and colleagues (1) were among the first to identify inaccuracies in oxygen readings inferred from pulse oximetry measurements. Black patients in the ICU had more than a 2-fold higher probability of falsely higher pulse oximetry readings compared to White patients in the ICU. Most studies in the 1990s and 2000s reaffirmed those concerns in various clinical settings. (3–5) Adler and colleagues (6) did not find differences in pulse oximetry measurement bias by skin color among patients in the emergency department, but one-third of darker skinned patients had “suboptimal” signals that could have been erroneous.