Light source spectra are the likely cause of systematic bias in pulse oximeter readings for individuals with darker skin pigmentation

Editor—Despite the findings of several studies from the 1990s to the contrary, 1 Adler J.N. Hughes L.A. Vtvilecchia R. Jr. CACEffect of skin pigmentation on pulse oximetry accuracy in the emergency department. Acad Emerg Med. 1998; 5: 965-970 Crossref PubMed Scopus (48) Google Scholar ,2 Bothma P.A. Joynt G.M. Lipman J. et al. Accuracy of pulse oximetry in pigmented patients. S Afr Med J. 1996; 86: 594-596 PubMed Google Scholar more recent empirical studies 3 Bickler P.E. Feiner J.R. Severinghaus J.W. Effects of skin pigmentation on pulse oximeter accuracy at low saturation. Anesthesiology. 2005; 102: 715-719 Crossref PubMed Scopus (215) Google Scholar , 4 Sjoding M.W. Dickson R.P. Iwashyna T.J. Gay S.E. Valley T.S. Racial bias in pulse oximetry measurement. New Engl J Med. 2020; 383: 2477-2478 Crossref PubMed Scopus (348) Google Scholar , 5 Cabanas A.M. Fuentes-Guajardo M. Latorre K. León D. Martín-Escudero P. Skin pigmentation influence on pulse oximetry accuracy: a systematic review and bibliometric analysis. Sensors. 2022; 22: 3402 Crossref PubMed Scopus (20) Google Scholar have documented that commercially available pulse oximeter measurements (SpO2) systematically overestimate arterial oxygen saturation levels (SaO2) for persons with dark skin at reduced oxygen saturation levels. This is where the accuracy of pulse oximetry is most critical. Because physicians heavily rely on pulse oximeter readings for diagnosis and treatment, this systematic bias practically means that individuals with relatively high concentrations of melanin in the skin might not reach the threshold for hospitalisation, escalation of care, or corrective interventions (88–92%), 6 Majumdar S.R. Eurich D.T. Gamble J.M. Senthilselvan A. Marrie T.J. Oxygen saturations less than 92% are associated with major adverse events in outpatients with pneumonia: a population-based cohort study. Clin Infect Dis. 2011; 52: 325-331 Crossref PubMed Scopus (87) Google Scholar thereby putting this group at greater risk for occult hypoxaemia and higher mortality than those with lightly pigmented skin. Although the problem has now become more widely recognised, there has been no satisfactory published explanation for this systematic bias. Improving pulse oximetry accuracy in dark-skinned patients: technical aspects and current regulationsBritish Journal of AnaesthesiaVol. 131Issue 4PreviewRecent concerns regarding the clinical accuracy of pulse oximetry in dark-skinned patients, specifically in detecting occult hypoxaemia, have motivated research on this topic and recently reported in this journal. We provide an overview of the technical aspects of the issue, the sources of inaccuracy, and the current regulations and limitations. These insights offer perspectives on how pulse oximetry can be improved to address these potential limitations. Full-Text PDF