Ttwo months after Democratic lawmakers expressed concern about potential racial disparities in pulse oximeter readings – calling the issue “life and death” – the Food and Drug Administration issued a public alert on devices Friday, recognizing that they they had “limitations”.
The warning comes decades after researchers first identified possible inaccuracies with the devices when used on people of color and months after a series of new studies produced new data underlining the problem. More recently, researchers at the University of Michigan published a letter from December 2020 in the New England Journal of Medicine that found that oximeters were almost three times more likely to miss hypoxemia in black patients compared to white patients.
“Be aware that several factors can affect the accuracy of reading a pulse oximeter, such as poor circulation, skin pigmentation, skin thickness, skin temperature, current use of tobacco and use of nail polish”, says the alert from the FDA.
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It does not explicitly mention racial disparities in the accuracy of devices, probably disappointing doctors and patients who have tried to draw attention to the problem.
“It is noticeable that the word ‘race’ or ‘racial’ is not mentioned in the FDA communication,” said Thomas Valley, a pulmonary intensive care physician and an author of the NEJM letter. “At the same time, what we found was a difference between black and white patients. We don’t know exactly why this difference existed, we assume it is the skin tone. “
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Pulse oximeters, which measure oxygen levels, have emerged as a particularly useful clinical tool in the midst of the Covid-19 pandemic due to the way the virus interferes with the body’s natural oxygen production. In hospitals, devices play a key role in making decisions about patient care. And at the end of last spring, after several professionals suggested that the devices could be useful to have at home (similar to the way someone might want to keep a thermometer in the medicine cabinet, for example), homemade versions of the devices started flying out of drugstore shelves and selling quickly on Amazon and other online sites.
But the December article – and its reference to a series of previous studies that document the same problem, including one published in 2005 – raised alarms among researchers and doctors, who said they were frustrated to learn that the issue had not been dealt with substantively. after 15 years.
“Not being confident in the accuracy of that number and relying on a device that may have a bias for a particular population is really worrying,” Utibe Essien, physician and assistant professor of medicine at the University of Pittsburgh School of Medicine, told STAT at the beginning Of this month.
In response to these concerns, William Maisel, director of the Office of Product Quality and Evaluation at the FDA’s Center for Devices and Radiological Health, told STAT that the agency was reviewing the available data and would consider further studies if necessary. He said the FDA is widely confident that hospital oximeters are highly accurate, but added that the same may not be true for devices sold online and in drugstores, which the agency does not review or approve.
Michael Sjoding, a pulmonologist at Michigan Medicine and author of the NEJM letter, said he was happy that the FDA emphasized the importance of not relying too much on pulse oximeters to make medical decisions in his statement. He added, however, that he thought the absence of an explicit mention of the race was a “missed opportunity”.
“GConsidering the limitations of our work … I suspect the FDA wants to be very cautious in its messages about racial disparities in pulse oximeter accuracy and to focus more on the problem of pulse oximeter imprecision more generally, ”he said.