Pulse Oximeters May Be Dangerously Inaccurate For Black Patients: Study

A new study suggests pulse oximeters used to measure oxygen levels in COVID-19 patients may provide dangerous misreadings for black patients, creating an increased risk of respiratory complications, blood circulation and inaccurately prescribed therapeutics.

Researchers from the University of Michigan published a letter to the editors of The New England Journal of Medicine on December 17, indicating black patients are nearly three times more likely to receive inaccurate or false readings from pulse oximeters than white patients, possibly delaying correct medical treatments and failing to alert medical professionals when patients’ hearts are not pumping enough oxygen through the body.

Pulse oximeters are one of the most commonly used monitoring tools in the medical community. They are designed to clip onto patients fingertips to measure the amount of oxygen flowing through their blood. Depending on the readings, patients are administered more or less supplemental oxygen and other therapeutic treatments based on levels of oxygen in the blood reported by the device.

Due to the way the coronavirus impacts the respiratory system, pulse oximeters have become increasingly popular for monitoring blood oxygen levels in hospital patients and also for individuals at home suffering shortness of breath or other COVID-19-like symptoms.

Researchers reviewed more than 48,000 blood oxygen measurements taken from patients receiving supplemental oxygen at either the University of Michigan Hospital between January and July or in intensive care units at 178 hospitals between 2014 and 2015.

When comparing for racial bias across the study results, researchers determined black patients were three times more likely to receive an inaccurate blood oxygen level reading, with 12% inaccuracy rate among Black patients and a 4% inaccuracy rate among those of lighter skin tones.

The researchers suspect darker pigments disrupt the ability of the pulse oximeter to report properly. They stated the light the pulse oximeter shines into fingertips to measure blood oxygen can be absorbed by skin pigment. Due to darker colors absorbing more light energy, this could be the cause of such inconsistencies among patients with darker skin tones.

Researchers indicated the results of their study should be used as a guidance for the medical community not to depend too heavily on monitoring patients’ blood oxygen levels through the use of only pulse oximeters, and that other measuring methods should be used to triage patients.

Given the potential inaccuracies of pulse oximeters discovered in the study, researchers also suggest individuals using the devices at home to monitor their health should focus more on the actual symptoms such as shortness of breath rather than the meter readings when determining if medical treatment is required. An inaccurate blood oxygen level reading while a patients is actually suffering hypoxemia could result delayed medical intervention and could cause potentially life-threatening adverse health consequences.

While the FDA does require reporting of demographic subgroups in device applications for market use, the findings of the study highlight the need for additional research to understand and correct racial bias, which could have major implications on the healthcare system, researchers determined.