Racial Bias in Pulse Oximetry Measurement Among Patients About to Undergo ECMO in 2019-2020, A Retrospective Cohort Study.

Abstract Background Pulse oximeters may be less accurate in non-White patients. Research Question Do pulse oximeter less effectively detect arterial hypoxemia in Black, Hispanic, and/or Asian patients than in White patients in respiratory failure about to initiate Extracorporeal Membrane Oxygenation (ECMO)? Study Design and Methods Extracorporeal Life Support Organization (ELSO) Registry of adult patients with respiratory failure readings 6 hours prior to ECMO from 324 centers, January 2019 and July 2020. Our primary analysis was of rates of occult hypoxemia—low arterial oxygen saturation (SaO2 ≤ 88%) on arterial blood gas despite a pulse oximetry reading in the ranges of 92-96%. Results The rate of pre-ECMO occult hypoxemia of SaO2 ≤ 88% was 10.2% (95%CI, 6.2%, 15.3%) for 186 White patients with SpO2 92-96%; 21.5% (95%CI, 11.3%, 35.3%) for 51 Black patients (p=0.031 vs White); 8.6% (95%CI 3.2%, 17.7%) for 70 Hispanic patients (p=0.693 vs White); and 9.2% (95%CI 3.5%, 19.0%) for 65 Asian patients (p=0.820 vs White). Black patients with respiratory failure had a statistically significantly higher risk of occult hypoxemia with an odds ratio (OR) of 2.57 (95%CI, 1.12, 5.92) compared to White patients (p=0.026). The risk of occult hypoxemia for Hispanic and Asian patients was equivalent to that of White patients. In a secondary analysis of patients with SaO2 ≤ 88% despite SpO2 >96%, Black patients had over three times the risk compared to White patients OR=3.52 (95% CI 1.12,11.10) p=0.032. Interpretation Compared to White patients, prevalence of occult hypoxemia was higher in Black patients than in White patients about to undergo ECMO for respiratory failure, but comparable in Hispanic and Asian patients to White patients.