Inaccurate pulse oximeter measurements delayed COVID treatment for people of color

AYESHA RASCOE, HOST:

You may have encountered this device at the hospital or even bought one for your home during the pandemic. A pulse oximeter is a fingertip clip that measures how much oxygen is in your blood - something that doctors need to know in order to treat COVID-19. But a study released last week shows how inaccurate measurements by the devices may have led to delays when treating people of color for COVID-19. Dr. Ashraf Fawzy is an assistant professor of medicine at Johns Hopkins University and co-author of the study, and he joins us now. Welcome.

ASHRAF FAWZY: Thank you, Ayesha. Thanks for having me.

RASCOE: Now, there has been knowledge for some time that pulse oximeters do not provide very accurate measurements for those with darker skin. I will say, I did not necessarily know that. But tell us what you found in this study.

FAWZY: So in our study, there were two parts. The first part - we looked at a large group of patients with COVID-19 and found that pulse oximeters overestimated the oxygen level in Black and Hispanic and Asian patients compared with white patients. This portion of the study replicates prior findings from a few other studies, and replication's very important in scientific research. The second part of the study - we tried to answer a new question. Did the inaccuracy of pulse oximeters potentially change how patients were cared for?

So in COVID, blood oxygen levels are used to determine whether a patient has severe COVID requiring treatment. Specifically, a blood oxygen level of 94% or less qualifies a patient for certain treatments - specifically dexamethasone, which is a steroid, and remdesivir, which is an antiviral medication. So what we found was that people of color, specifically Black and Hispanic patients, were 29% and 23% less likely than white patients to have severe COVID identified, which means that the recognition of the need for medication was potentially delayed.

RASCOE: Do we know why pulse oximeters don't work as well on darker skin?

FAWZY: Well, the assumption is that it is darker skin, but there aren't really any studies that really show this. But that's the leading assumption.

RASCOE: So at the start of the pandemic, you know, I started hearing these things about, OK, you need to get a pulse oximeter. I sent a pulse oximeter to my aunt when she got sick. I had my sister in my house when my husband got COVID. I got the pulse oximeter. Like, was I wrong to be using it that way, as - and I am Black. You know, people probably know that. But I'm a Black woman. My family is Black. Should we not do that - use them at home like that?

FAWZY: Well, pulse oximetry is the fifth vital sign. So other vital sign examples, for instance, are temperature and blood pressure. So knowing the oxygen level in your blood is extremely important. So it certainly wasn't wrong to get them and use them. It's just important to know that they may not be a hundred percent accurate. So if things don't necessarily line up, if the way you're feeling doesn't line up with the way - with what the pulse oximeter is telling you, then that might be a good reason to seek medical care and not just solely rely on the pulse oximeter reading.

RASCOE: I wanted to go back to your research and ask about how - we know that Black communities and communities of color have had some of the worst outcomes in terms of death and hospitalization during the pandemic. Does your research findings add any data to whether this may have played a role in those worse outcomes or have been one of the factors?

FAWZY: It may certainly be one piece of the puzzle. So we weren't able to look at outcomes like whether there's a higher death rate or more disability, longer hospitalizations in our study, unfortunately. But certainly, other studies have shown that racial and ethnic minorities have had worse outcomes with COVID, and treatment is definitely one of the important things that help reduce the death rate and lead to better outcomes. So the fact that we are showing that there is a potential delay in treatment among those patients may be a piece of the puzzle as to why Black and Hispanic patients were doing worse at the beginning of the pandemic.

RASCOE: What do you think needs to happen to address this issue? Does there need to be more education about this?

FAWZY: More education is definitely important for the time being. But ultimately, there needs to be a more permanent fix. With evidence mounting that the device is not equally accurate among all races, hopefully this is the catalyst for the medical community to reengineer the pulse oximeters so they work more equitably for all patients.

RASCOE: Dr. Ashraf Fawzy is an assistant professor of medicine at Johns Hopkins University. Thank you so much for joining us.

FAWZY: You're welcome, Ayesha. Thank you for having me. Transcript provided by NPR, Copyright NPR.