More Evidence That Racial Inequities Exist in Pulse Oximeter Use

A study published in The BMJ shows that differences in the results from arterial blood gas readings and pulse oximetry led to racial inequities in care, preventing Black people from obtaining necessary treatment for occult hypoxemia or low blood oxygen saturation levels.

Researchers conducted a retrospective cohort study using EMR data from the Veterans Health Administration. They used occult hypoxemia as a primary measure, which was calculated using arterial blood oxygen saturation measurements and pulse oximetry.

The evaluation of health disparities is becoming a common practice in healthcare, as their presence became starker during the COVID-19 pandemic. In this study, researchers sought to determine whether differences in occult hypoxemia treatment existed between people of different races.

Occult hypoxemia was defined as arterial blood oxygen saturation of less than 88 percent despite a pulse oximetry reading of 92 percent or more.

Overall, 30,039 pairs of pulse oximetry and arterial blood oxygen saturation readings took place in the research process. Of these pairs, 73 percent belonged to non-Hispanic White people, 21.6 percent to non-Hispanic Black people, and 5.4 percent to Hispanic or Latino people.

In White patients, pulse oximetry levels that exceeded 92 percent correlated with a 15.6 percent likelihood of occult hypoxemia as measured by an arterial blood oxygen saturation of less than 88 percent. This pulse oximeter reading was also linked to a 19.6 percent chance of blood oxygen saturation-measured occult hypoxemia in Black patients and a 16.2 percent chance in Hispanic or Latino patients.

Thus, Black patients had higher odds than their White counterparts of having occult hypoxemia as measured by arterial blood oxygen saturation but not detected by pulse oximetry.

Researchers also noted that White patients with pulse oximetry and arterial blood oxygen saturation readings that occurred within 5 minutes and 2 minutes had a 2.7 percent chance of a future arterial blood oxygen saturation reading of lower than 88 percent paired with a pulse oximetry reading of 92 percent. Black patients, however, had a higher chance at 12.9 percent.

There are several limitations to the study, mainly that pulse oximetry measurements occur more frequently than arterial blood oxygen, the lack of clarity when collecting data regarding race, and the fact that all study participants had a resume containing military service.

However, based on these results, researchers concluded that Black patients were more likely than White patients to have occult hypoxemia measured by arterial blood oxygen saturation but not pulse oximetry. The differences between the two measurements may lead to Black patients facing barriers when accessing care.

The clinical evidence showing racial discrepancies in pulse oximetry use is mounting.

A study published in June described how the use of pulse oximeters led to care disparities, preventing minority groups from obtaining COVID-19 care. After gathering patients with occult hypoxemia, researchers divided them by race and ethnicity, only to find that pulse oximeter readings for Asian, Black, and Hispanic patients overestimated arterial blood oxygen saturation levels.

Another study published in July revealed that inaccurate pulse oximeter readings led to disparities in delivering supplemental oxygen to patients, mainly affecting Asian, Black, and Hispanic people.