Health

Study: Pulse oximeters don’t work as well on people of color, causing uneven healthcare

Black, Hispanic, and Asian patients had greater discrepancies in readings and received less supplemental oxygen than white patients.

By Ross Cristantiello

July 11, 2022

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Racial disparities in care among hospital patients may be tied to inaccuracies in pulse oximeter readings, a new study found. The research, led by a team from Brigham and Women’s Hospital and Beth Israel Deaconess Medical Center, found that Black, Hispanic, and Asian patients had greater discrepancies in pulse oximeter readings while also receiving less supplemental oxygen than white patients.

Pulse oximeters are a commonly used device, used to quickly measure a person’s oxygen saturation. They are placed on a finger or an ear lobe to make readings, but can be hampered by the color of a person’s skin, according to a release from Mass General Brigham. Skin pigmentation and melanin can impact how accurately a pulse oximeter measures oxygen saturation. This has been common knowledge in the medical community for decades, the hospital said.

But new evidence shows that those inaccuracies may lead to differing levels of care between patients. 

“It’s important to keep in mind that pulse oximeters give us an estimate, but it’s more than just a number. We use that estimate to make clinical decisions, such as how much supplemental oxygen to give a patient,” author Eric Gottlieb said in a statement. “It has real meaning for the patients that we care for because we can track back racial disparities in treatment to these differences in measurements.”

The most accurate way to measure oxygen saturation is to take a blood sample, but pulse oximeters are often quicker and less of a nuisance for patients. Black, Hispanic, and Asian patients treated in the Intensive Care Unit had larger discrepancies than white patients between their oxygen saturation levels detected using pulse oximeters compared to levels detected with blood tests. They also received less supplemental oxygen than white patients, according to the release. 

Pulse oximeters work by measuring the amount of light passing through one’s skin, estimating how much oxygen currently exists in a patient’s red blood cells. The blood samples, while more accurate, require either inserting a needle into the radial artery in the wrist or putting in an arterial line. 

If a patient’s oxygen saturation level reading is inaccurately high, they could be more prone to hidden hypoxemia. This condition is both associated with higher mortality rates and one that occurs more frequently among racial and ethnic minority patients, according to the release. 

For this study, investigators used critical care data from thousands of patients admitted to the ICU at Beth Israel. 

More than 3,000 participants were included in the study, according to the release. Among them, 2,667 were white, 207 were Black, 112 were Hispanic, and 83 were Asian.  

“Understanding biases that exist within real-world data is crucial before we use them to train algorithms to assist clinicians with decision-making,” said Leo Anthony Celi of Beth Israel. “Before we invest more money on developing artificial intelligence for healthcare using electronic health records, we have to recognize all the drivers of outcome disparities including those that arise from the use of technology. Otherwise, we risk perpetuating and magnifying health inequities with artificial intelligence.”

The study’s limitations were noted by its authors. For one, these findings are based on data from just one location. The study also included only patients who received supplemental oxygen by nasal tubes. Additionally, race and ethnicity were self-reported and not assessed by skin tone, the release said. 

Studies diving into this topic in the future could find ways to more directly measure skin tone and oxygen delivery, as well as examining other sociodemographic factors that might contribute to disparities.

“To date, there has been limited interest in solving the problems inherent in pulse oximeters, but we show that these measurements are clinically relevant and pose a real problem that needs to be solved,” said Gottlieb. “It’s important that this kind of research continue and clinicians engage with engineers, regulators and other stakeholders to insist that this is an issue worth addressing.”