Non-white ICU patients receive less oxygen than is required, according to a study.

According to data from a sizable study released on Monday, critically ill Asians, Blacks, and Hispanic patients receive less supplementary oxygen to help them breathe than white patients due to a defect in a frequently used medical device that measures oxygen levels.

Red and infrared light are sent through the skin by pulse oximeters to measure the blood’s oxygen content. Since the 1970s, it has been recognised that variations in skin pigment can affect readings, but it was not thought that these differences would have an impact on 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

In the study that was published in JAMA Internal Medicine, blood oxygen levels were directly measured rather than using pulse oximetry, which is not practical for the average patient because it involves a painful intrusive procedure.

Despite pulse oximeter readings of 92 percent to 96 percent, the authors of a separate study involving patients with COVID-19 observed ‘occult hypoxemia,’ or an oxygen saturation level below 88 percent, in 3.7 percent of blood samples from Asian patients, 3.7 percent of Black patients, 2.8 percent of non-Black Hispanic patients, and just 1.7 percent of samples from white patients. Only 17.2 percent of individuals with occult hypoxemia were white.

‘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 published with the study, told Reuters.

Medtronic Plc (MDT.N) executive Frank Chan said in an emailed statement that the company confirms accuracy of its pulse oximeters ‘by taking synchronized blood samples at each level of blood oxygen content and comparing the pulse ox readings with measurements made from the blood sample.’

He continued, ‘to assure our technology will operate as intended for all patient demographics, Medtronic evaluates its devices on a higher than required number of volunteers with dark skin pigmentation.’

A request for comment was not answered by Phillips Healthcare, the manufacturer of pulse oximeters.