A flaw in a widely used medical device that measures oxygen levels causes critically ill Asians, Blacks and Hispanics to receive less supplemental oxygen to help them breathe than white patients, according to data from a large study published on Monday.
Pulse oximeters clip onto a fingertip and pass red and infrared light through the skin to gauge oxygen levels in the blood. It has been known since the 1970s that skin pigmentation can throw off readings, but the discrepancies were not believed to affect patient care.
Among 3,069 patients treated in a Boston intensive care unit (ICU) between 2008 and 2019, people of color were given significantly less supplemental oxygen than would be considered optimal compared to white people because of inaccuracies in pulse oximeter readings related to their skin pigment, the study found.
"Nurses and doctors make the wrong decisions and end up giving less oxygen to people of color because they are fooled" by incorrect readings from pulse oximeters, said Dr. Leo Anthony Celi of Harvard Medical School and the Massachusetts Institute of Technology, who oversaw the study.
For the study, pulse oximetry readings were checked against direct measurement of blood oxygen levels, which is not practical in the average patient because it requires a painful invasive procedure.
Researchers saw "occult hypoxemia" - an oxygen saturation level below 88% despite pulse oximeter readings of 92% to 96% - in 3.7% of blood samples from Asian patients, 3.7% of samples from Black patients, 2.8% of samples from non-Black Hispanic patients versus just 1.7% of samples from white patients, according to the report published in JAMA Internal Medicine https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2794196. Whites accounted for only 17.2% of all patients with occult hypoxemia at some point during their hospital stay.
A separate team reported recently in the same journal https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2792653 that racial and ethnic biases in pulse oximetry accuracy have resulted in delayed or withheld treatments among Black and Hispanic patients with COVID-19.
Pulse oximetry can also be affected by obesity, medications used in critically ill patients, and other factors, Celi said.
Imarc Group market research firm forecast the global pulse oximeter market reaching $3.25 billion by 2027, following 2021 sales of $2.14 billion.
"We think it's very reasonable at this point to call upon purchasers and manufacturers to make changes (to the devices), Dr. Eric Ward, coauthor of an editorial https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2794204 published with the study, told Reuters.
