Pulse oximeter inaccuracy may be linked to racial disparities in care

For most patients, the pulse oximeter is a familiar tool from doctor’s office visits. Placed on a finger or the lobe of a patient’s ear, a pulse oximeter is an easy way to quickly measure one’s oxygen saturation (SpO2), which should usually be above 90 percent. But this device may contribute to disparities in care based on patient’s breed. For decades, it has been known that skin pigmentation and melanin can affect the pulse oximeter’s ability to accurately measure oxygen saturation.

A new study, led by investigators at Brigham and Women’s Hospital and Beth Israel Deaconess Medical Center (BIDMC), finds evidence that those errors may also be linked to inequalities in care. The researchers found that, compared to white patients, black, Hispanic and Asian patients treated in the intensive care unit (ICU) had more discrepancies between SpO2 levels detected using a pulse oximeter versus levels detected in blood samples. and had received less supplemental oxygen than white patients. results are published in JAMA Internal Medicine.

“It is important to note that pulse oximeters give us an estimate, but it is more than just a number. We use that estimate to make clinical decisions, such as how much supplemental oxygen to give to the patient. ,” said corresponding author Eric Gottlieb, MD, MS, who completed this work as a fellow in the Renal Division at Brigham and in the Laboratory for Computational Physiology (LCP) at MIT. “This has real meaning for the patients we care for because we can track racial disparities back in treatment for these differences in measurement.”

Pulse oximeters measure how much light passes through the skin to get an idea of ​​how much oxygen is in a patient’s red blood cells. The most accurate way to measure true blood hemoglobin oxygen saturation level is to take a sample of the patient’s arterial blood, which requires insertion of a needle into the radial artery in the wrist or into the arterial line -; Procedures that are uncomfortable for patients and which cannot be performed routinely or as easily as taking measurements with a pulse oximeter. When a patient has falsely elevated SpO2 readings, they may be at higher risk for latent hypoxemia. A condition associated with high mortality and one that occurs at a higher incidence in racial and ethnic minority patients.

To conduct their study, Gottlieb and colleagues used data from the MIMIC-IV critical care dataset, which includes critical care data for more than 50,000 patients admitted to intensive care units at BIDMC. This dataset includes both pulse oximeter readings and oxygen saturation levels detected in patient blood samples for patients in the ICU. The dataset also includes rates of supplemental oxygen, provided by nasal cannula.

The study included more than 3,000 participants, of whom 2,667 were white, 207 were black, 112 were Hispanic and 83 were Asian. When researchers compared SpO2 levels taken by pulse oximeters from blood samples to oxygen saturation, they found that Black, Hispanic, and Asian patients had higher SpO2 readings than white patients for a given blood oxygen saturation level. Was. As a result, black, Hispanic and Asian patients also received lower rates of supplemental oxygen.

“It is important to understand the biases that exist within real-world data before we can train algorithms to aid decision-making clinicians,” said senior Leo Anthony Seely, MD, MS, MPH in the Department of Medicine at Beth Israel Deaconess Medical. Use them to do that.” hub. “Before we invest more money on developing artificial intelligence for health care using electronic health records, we need to identify all drivers of outcome disparities, including those that result from the use of technology. Otherwise, we may end up with artificial intelligence.” together run the risk of perpetuating and increasing health inequalities.”

The authors noted the limitations of their study, that their findings are based on data from one institution, included only patients receiving supplemental oxygen by nasal cannula, and were self-reported by race/ethnicity and skin. Key tone was not rated by. Future studies may measure skin tone and oxygen delivery more directly and investigate other comorbidities and sociodemographic factors that may 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 there is a real problem that needs to be solved,” Gottlieb said. “It is important that this kind of research continues and physicians engage with engineers, regulators and other stakeholders to emphasize that this is an issue worth addressing.”