From the Journals

Racial bias in pulse oximetry results confirmed


NEW YORK (Reuters) – Pulse oximeters are significantly more likely to miss low oxygen levels in Blacks than in Whites, a new study confirms.

Using the Extracorporeal Life Support Organization (ELSO) registry, researchers at the University of Michigan, Ann Arbor, did a retrospective study of adults with respiratory failure because of acute respiratory distress syndrome (ARDS) or COVID-19 who were placed on extracorporeal membrane oxygenation (ECMO).

The primary analysis focused on rates of occult hypoxemia – low arterial oxygen saturation (SaO2) 88% or less on arterial blood gas despite a pulse oximetry reading in the ranges of 92%-96%.

The rate of pre-ECMO occult hypoxemia of SaO2 88% or less was 10.2% for 186 White patients with peripheral oxygen saturation (SpO2) of 92%-96%; 21.5% for 51 Black patients (P = .031); 8.6% for 70 Hispanic patients (P = .693); and 9.2% for 65 Asian patients (P = .820).

Black patients with respiratory failure had a statistically significantly higher risk of occult hypoxemia with an odds ratio of 2.57 (95% confidence interval, 1.12-5.92), compared with White patients, Dr. Valeria Valbuena and colleagues reported in the journal CHEST.

The risk of occult hypoxemia for Hispanic and Asian patients was no different to that of White patients.

In a secondary analysis of patients with SaO2 88% or less despite SpO2 greater than 96%, Black patients had over three times the odds, compared with White patients (OR, 3.52; 95% CI, 1.12-11.10).

The current findings support and extend an earlier study by the U-M team involving patients receiving supplemental oxygen in which Black patients were three times more likely to have occult hypoxemia compared to white patients.

The current study documents significant differences in the ability of current pulse oximetry devices to detect occult hypoxemia between critically ill patients of white and Black patients, they pointed out.

“Our findings join the body of evidence suggesting that the use of SpO2 to rule out acute hypoxia, particularly in Black patients with other concerning signs or symptoms, should be reevaluated given its diminished reliability,” the authors wrote.

“Also concerning is the limitation of the technology to identify clinically significant hypoxemia for Black patients at higher SpO2 levels,” they added.

“At an SpO2 range of greater than 96%, most clinicians would be reassured about the oxygenation status of even critically ill patients with respiratory failure, but our findings indicate that reassurance may be unwarranted. Given the widespread use of pulse oximetry, a higher degree of suspicion of hypoxemia for patients of color should be considered with consideration of more frequent use of arterial blood gas examination for patients at risk until a technological fix is implemented,” they advised.

Earlier this year, three U.S. senators sent a letter to the commissioner of the Food and Drug Administration requesting an expedited review of device sensitivity in patients of different races.

Reuters Health Information © 2021

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