The New York Times reported that, based on a study that had its findings shared with the New England Journal of Medicine, the devices can provide misleading results in more than one out of 10 of Black patients.
Pulse oximeters can measure the saturation of oxygen in red blood cells by shining a light through the skin when clipped to the user’s body. They can be used at home for people with underlying health conditions and are sold online and in pharmacies and other common marketplaces.
Early on in the COVID-19 pandemic, the general public had the realization that pulse oximeters might be helpful in detecting oxygenation problems and elevated heart rates, significant signs of COVID-19, leading to a free-for-all for the devices. The NBA even signed a deal with Masimo (NSDQ:MASI), which became its official supplier of pulse oximetry when the league returned to play this last summer in a “bubble-style” camp format.
With Black patients, who have proven to be more at-risk during the pandemic, among other racial minority populations, the potentially misleading results from the devices could add to the struggle of the pandemic, which has seen acutely ill black patients turned away when seeking medical care, according to the New York Times report.
An analysis of 10,789 paired test results from 1,333 white patients and 276 Black patients hospitalized at the University of Michigan found that the pulse oximetry overestimated oxygen levels 3.6% of the time in white patients but provided misleading results almost 12% of the time in Black patients.
In the Black patient population, the measurements indicated an oxygen saturation level between 92% and 96% — with oxygen levels below 95% considered abnormal — when the actual oxygen saturation level reached as low as 88%, meaning even a small miscalculation in the measurement could make the difference between knowing if a patient is really sick or not.
A similar analysis compared 37,308 paired test results from ICU patients hospitalized across 178 medical centers in 2014 and 2015 and found similar discrepancies, the report said.
Masimo founder & CEO Joe Kiani told MassDevice via email that skin pigmentation has represented a challenge in pulse oximetry, with dark pigmentation sometimes resulting in overestimation.
A study in 2007 finding that Nellcor (now part of Medtronic) and Nonin overestimated on pulse oximetry for several disposable pulse oximeter probes (overestimations were 3.6% and 2.4%, respectively). Masimo LNOP sensors underestimated by 1.6% in that same study. A more recent 2017 study of infants with hypoxemia compared Masimo and Medtronic pulse oximeters and found “no significant difference in systematic bias based on skin pigment” in either device.
Kiani said Masimo is orchestrating an active research effort to improve accuracy in pulse oximetry, translating directly into improved precision and bias on all subjects, regardless of skin tone. Internal studies have shown the company’s RD SET series sensors have similar accuracy on both light and dark pigmented subjects, Kiani noted.
This story was updated with information provided by Masimo.