Blood oxygen monitors miss concerning COVID-19 symptoms more often in patients of color

Blood oxygen monitors said hospitalized Asian, Black and Hispanic COVID-19 patients had higher blood oxygen levels than they actually had, according to a new study. Oxygen levels are an important indicator of how severe a person’s case of COVID-19 is and which drugs they qualify for — and that overestimation meant it took longer for black and Hispanic patients to receive the necessary treatment.

Pulse oximeters, the standard way clinics and hospitals measure blood oxygen, work by sending red and infrared light through the fingertip and measuring the amount reflected back. (Hemoglobin, the protein in the blood that carries oxygen, absorbs more infrared light when it carries oxygen). For yearsstudies have shown that those devices don’t work as well on dark-skinned people.

In this new study published in the magazine JAMA Internal Medicine, a research team looked at patients with COVID-19 at the Johns Hopkins Health System between March 2020 and November 2021. In just over 1,200 patients, oxygen levels were checked by both pulse oximeters and a more accurate blood test was performed. In about 30 percent of Asian, Black and Hispanic patients, the blood test showed low oxygen levels in the blood when the pulse oximeter said the levels were normal. That was the case in only 17 percent of white patients.

In a larger group of more than 6,600 patients, the research team found 1,903 patients where a model showed that their oxygen levels would have dropped before the pulse oximeter showed it to. In that group, black and Hispanic patients were more likely to experience delays in receiving treatments such as remdesivir (which most hospitals only gave to patients with oxygen levels below 94 percent) or dexamethasone (which most hospitals only gave to patients). receiving supplemental oxygen). †

Of that group, 451 patients were never marked as eligible for treatment. More than half of those patients were black. It took black patients who ended up being treated about an hour longer than white patients to qualify as eligible.

Other research in recent years has come to similar conclusions. a study published in November 2021, for example, also showed that gaps between oxygen levels measured on a blood test and on a pulse oximeter were more likely for non-white patients in hospitals than for white patients. Patients with that gap were more likely to have organ problems and death in the hospital. The Food and Drug Administration warned in February 2021 that the pulse oximeter readings had “limitations” and that skin color can affect the readings.

But despite the well-documented flaws, no major steps have been taken to correct the bias, researchers wrote an editor in the new study. “Hospitals and practitioners continue to buy and use these devices despite their inaccuracy for non-white patients,” they said. It’s not an easy problem to solve, and pulse oximeters are generally a less accurate measure of oxygen in the blood. But hospitals and regulators should push to only allow devices that perform the same on different skin tones, and doctors can adjust their treatment methods to spot potential flaws in their non-white patients.

“While the device measurement error is real and based purely on optics, the decision to do nothing about a faulty device is a human decision and one that can and should be corrected,” they wrote.


Leave a Reply

Your email address will not be published.