Pulse oximeters are a critical healthcare tool that in a time of need can mean the difference between life and death for someone who is sick. At the start of the pandemic, between March and June of 2020, the sale of pulse oximeters for home use increased by 500%. While pulse oximeters are an undeniably powerful medical tool, researchers and advocates have raised concerns about the limits of their effectiveness for some people of color.
A pulse oximeter is a device that measures your blood oxygen level. Blood oxygen information is crucial to life, and is often used by healthcare providers to provide better care for their patients. Home use is also sometimes warranted for certain individuals.
According to Nihon Koheden, the company which first patented the device, “It can be fatal if there is not enough oxygen in the blood. Blood sampling does not always provide accurate, real-time information about the patient’s condition, which changes over time, but using a pulse oximeter does not hurt the patient and allows the surgeon to understand, in real time, how much oxygen the patient has in their bloodstream.” Like many medical devices, the pulse oximeter wasn’t created with Black people in mind and the effectiveness of pulse oximeters for people of color is not as high as it is for people with lighter skin.
Dr. Eric Gottlieb, a lecturer at MIT and a physician at Mount Auburn Hospital in Cambridge, Massachusetts who co-authored a study a recent study, when Hewlett Packard developed its pulse oximeter in the 1970s, said the company was aware of issues regarding accurate readings for non-white individuals and “put a lot of effort into trying to solve it, making these devices more equitable.”
However, over time, issues around equity and accuracy of pulse oximeters remained. According to Gottlieb, pulse oximeters “are very, very important and I wouldn’t say that they should be removed from practice, but the question of equity until the last couple of years sort of fell off the radar screen and then there was a renewed interest and then of course even more interest with COVID both in terms of their accuracy and how they should be used.”
This assessment is shared by author Amy Moran-Thomas, an associate professor of anthropology at MIT. Studies over the intervening decades continue to show issues with oximeters and skin tone, but the COVID pandemic brought the issue back into sharp focus.
Gottlieb said that when a patient’s pulse oximeter readings are higher, “we assume [patients are] oxygenating a little bit better so our treatment of oxygenation will probably be less intensive.” This, according to Gottlieb, can lead to “disparities in treatment.”
As for solutions and next steps, there is research currently being conducted to improve readings for people with darker skin tones. Rutendo Jakachira, a second-year Ph.D. student at Brown University in the Department of Physics, in partnership with Brown University Professor of Engineering Kimani C. Toussaint, is conducting research to create a non-invasive method of obtaining accurate blood oxygen readings from people with darker skin.
If you already have a pulse oximeter at home, it is vital that you take readings (and write them down) when you are healthy and not feeling sick. This will provide you with an important baseline to understand the readings you take when you are feeling ill.
Pulse oximeters can be helpful but, according to the FDA, the limits of the devices mean that you should take immediate action if you see:
Bluish coloring in the face, lips, or nails;
Shortness of breath, difficulty breathing, or a cough that gets worse;
Restlessness and discomfort;
Chest pain or tightness; and
Fast or racing pulse rate.
When using a pulse oximeter it is essential to write down the measurements, dates and times so you and your doctor can easily track your oxygen level. If you see your oxygen level going down over time, and much lower than previous readings you took when you were not feeling sick, and/or your symptoms increase or worsen, you should contact your doctor or visit an emergency room as soon as possible.