Critical care trainees call for pulse oximetry reform

Abstract

Oxygen saturation via pulse oximetry is arguably the most relevant vital sign in pulmonary medicine. Yet, decades of research assessing SpO2 have consistently shown inconsistencies in its accuracy as an estimation of arterial haemoglobin oxygen saturation in Black patients. In the early 1990s, it was noted that Black patients often have falsely elevated SpO2 readings, and that using pulse oximetry to target an SpO2 of 92% in Black patients was associated with inaccurate oximetry readings and substantial hypoxaemia.1Jubran A Tobin MJ Reliability of pulse oximetry in titrating supplemental oxygen therapy in ventilator-dependent patients.Chest. 1990; 97: 1420-1425Summary Full Text Full Text PDF PubMed Scopus (115) Google Scholar Since the 1990s, additional analyses have found similar conclusions.2Severinghaus JW Kelleher JF Recent developments in pulse oximetry.Anesthesiology. 1992; 76: 1018-1038Crossref PubMed Scopus (240) Google Scholar, 3Feiner JR Severinghaus JW Bickler PE Dark skin decreases the accuracy of pulse oximeters at low oxygen saturation: the effects of oximeter probe type and gender.Anesth Analg. 2007; 105: S18-S23Crossref PubMed Scopus (117) Google Scholar Most recently, in a 2020 study of the accuracy of pulse oximetry in adult patients receiving supplemental oxygen, occult hypoxaemia was identified more frequently in Black patients compared with White patients.4Sjoding MW Dickson RP Iwashyna TJ Gay SE Valley TS Racial bias in pulse oximetry measurement.N Engl J Med. 2020; 383: 2477-2478Crossref PubMed Scopus (96) Google Scholar Together, these studies show the differential inaccuracy and inconsistency of pulse oximetry in estimating SaO2 in Black patients, suggesting that such patients might be at higher risk of adverse events due to inaccuracy of existing medical devices. The cumulative harm of inaccurate measurements via pulse oximetry remains unquantified, but given the wide use of oxygen as a therapeutic intervention it is implausible that systemic hypoxaemia has not caused excess harm. The differential inaccuracy of pulse oximetry is an example of systemic racism in health-care delivery that has not been addressed despite decades of evidence. Pulse oximeters are not hypersensitive in White patients but under detect hypoxaemia in Black patients, which is an example of White patients being used as the default. There is an immediate urgency to address the inaccuracy of pulse oximeters, especially during a pandemic that has already disproportionately affected communities of colour.5Lopez 3rd, L Hart 3rd, LH Katz MH Racial and ethnic health disparities related to covid-19.JAMA. 2021; (published online Jan 22.)https://doi.org/10.1001/jama.2020.26443Crossref PubMed Scopus (95) Google Scholar The fact that this imprecision in pulse oximetry has been reported for over 30 years and has not been systemically addressed speaks volumes of the unwillingness of those in leadership to do what is right for minoritised patients. Recently, the US Food and Drug Administration (FDA) has tried to address this by providing recommendations for both patients and providers, as well as disclosing limitations of pulse oximeters. We find these efforts insufficient, as literature regarding inaccuracies has been published as early as 1990, so any attempt short of testing pulse oximeters in a large, diverse population to ensure trustworthiness will not suffice.6US Food and Drug AdministrationPulse oximeter accuracy and limitations: FDA safety communication.https://www.fda.gov/medical-devices/safety-communications/pulse-oximeter-accuracy-and-limitations-fda-safety-communication?utm_medium=email&utm_source=govdeliveryDate: Feb 19, 2021Date accessed: February 26, 2021Google Scholar We are compelled to advocate to ensure that our patients are not harmed by the medical devices used to monitor the care we provide. Specifically, we call on our regulatory bodies—the FDA, the European Medicines Agency (EMA), and the UK Medical and Healthcare Products Regulatory Agency (MHRA)—to conduct an immediate review of the accuracy of pulse oximeters in patients of colour and to only approve oximeters that are proven to perform equivalently in White patients and patients of colour in the clinically relevant range of 88–96%. We call on the pulmonary and critical care academic societies to urge the FDA, EMA, and MHRA to ensure pulse oximeters undergo rigorous testing in diverse patient populations, and to make such regulatory reform a priority in their lobbying. Finally, we call on hospitals to commit to only purchasing pulse oximeters that have been shown to work equally well in patients of colour. It was devastating to learn that one of the tools on which we rely is probably causing harm to people of colour. As critical care trainees, with long careers ahead caring for patients, we demand change. We declare no competing interests.