Study: Pulse oximeters tend to give inaccurate readings for people with darker skin
Black patients experienced delays in COVID-19 treatment because of the problem, said Kristen Azar with Sutter Health’s Institute for Advancing Health Equity
By Marcus D. Smith
The Sacramento Bee
SACRAMENTO — Black patients experienced delays in COVID-19 treatment because a common medical device that measures blood oxygen levels tended to give inaccurate readings for darker-skinned individuals, according to a new study by Sutter Health.
The inaccurate measurements contributed to nearly five-hour delays in COVID-19 treatment, which was critical time for the potentially fatal virus, according to the study.
“The findings underscore the fact that bias is not only human, but it can also be ingrained in the devices and tools clinicians rely on, too,” said Dr. Stephanie Brown of Sutter Health’s Institute for Advancing Health Equity. “To build a more equitable healthcare system we must continue to not only uncover where bias exists in medicine but also work to understand its impact on clinical outcomes and how it can be corrected.”
The devices, pulse oximeters, are clipped on to a finger or ear lobe. They use light beams to estimate oxygen saturation in blood and a person’s pulse rate.
The Food and Drug Administration in 2021 issued special guidance on pulse oximeters because of their heavy use during the pandemic. It noted their accuracy depended on many factors, such as circulation, skin pigmentation, skin thickness, skin temperature, current tobacco use, and use of fingernail polish.
Kristen Azar, medical director of Sutter Health’s Institute for Advancing Health Equity, said previous studies showed the pulse oximeter overestimated oxygen levels for Black individuals.
As a result, “it was harder for clinicians to appropriately treat their Black patients suffering from COVID-19 which resulted in measurable treatment delays and contributed to structural racism in health care, regardless of clinician intent,” Azar said.
The new Sutter analysis determined blood oxygenation was connected to delayed supplemental oxygen treatment up to four-and-a-half hours, delayed dexamethasone treatment up to 37 minutes, a lower probability of receiving supplemental oxygen treatment and a lower probability of being admitted into a hospital.
Dr. Noha Aboelata, CEO of the Roots Community Health Center in Oakland, California, called the study “disturbing” given that pulse oximeters or so commonly used in health care and that they were know to be less accurate for people with darker skin tones.
“We should all be pretty outraged about this situation,” said Aboelata, a co-author of the study. “Replace these devices with accurate devices. This is 2022.”
Aboelata, also one of the study’s co-authors, said the death disparities for African American people was a wide gap during the earlier stages of the pandemic, even accounting for the underlying health issues that existed in some patients.
Brown wants the FDA to reevaluate its policies around approving pulse oximeters for clinical use, manufacturers to provide tools that are free from bias, and clinicians to have a heightened sense of suspicion regarding the accuracy of results produced by a device.