Blood oxygen kits don't work well on non-white patients - Futurity

Blood oxygen kits don’t work well on non-white patients – Futurity

A new study shows that pulse oximeters — instruments that measure blood oxygen levels that are used in nearly every US hospital — overestimate blood oxygen levels in non-white patients.

A retrospective analysis of more than 7,000 patients with COVID-19 shows that inaccuracies made these patients appear healthier than they were and delayed recognition of their eligibility for specific COVID-19 medications recommended by the Centers for Disease Control and Prevention.

At sea level, the level of oxygen in the blood should be between 95% and 100%. Patients infected with COVID-19, which causes low oxygen levels, are at risk of contracting the disease if their levels fall below this range.

Ashraf Fawzy, MD, associate professor of medicine at Johns Hopkins University School of Medicine and co-lead author of the study in JAMA Internal Medicine.

But if pulse oximetry overestimates a patient’s blood oxygen levels, it may delay treatment or prematurely underestimate treatment. Our aim with this analysis was to investigate whether there was a bias in pulse oximeter readings by race and ethnicity among COVID-19 patients and whether this bias led to a delay in care.”

For the study, researchers looked at patient data collected from the Johns Hopkins Center for Precision Medicine of Excellence for COVID-19. Initially, the team focused on more than 1,200 patients with COVID-19 who simultaneously underwent two tests that measure oxygen levels in the blood: pulse oximetry and an arterial blood gas (ABG) test.

Via a clamp device, the pulse oximeter indirectly measures the oxygen levels in a patient’s blood using wavelengths of light. Conversely, ABG tests require a blood sample for direct measurement. Most patients take only few, if any, ABG tests during an extended hospital stay. Medical practitioners frequently use the noninvasive method of oximetry.

The team compared patients’ ABG test results with those of pulse oximetry and found that pulse oximetry overestimated blood oxygenation in racial and ethnic minorities.

Compared with white patients, pulse oximetry overestimated blood oxygen levels by 1.2% for black patients, 1.1% among non-Hispanic black patients, and 1.7% for Asian patients.

To estimate the effect of this bias, the team then looked at more than 6,600 other patients with COVID-19. By applying a statistical prediction model, the researchers found that more than a quarter of these patients — most of whom are racial or ethnic minorities — may qualify for additional treatment for COVID-19 before the pulse oximeter recognizes it. Overall, the researchers found that black and non-Hispanic black patients were 29% and 23% less likely, respectively, than white patients to identify eligibility for treatment by pulse oximetry.

says co-lead author Tianshi David Wu, MD, associate professor of medicine at Baylor College of Medicine.

“We’ve shown that biases in pulse oximetry accuracy can mean the difference between receiving and not receiving an essential drug – and crucially, we were able to determine how disproportionately this affects minority communities.”

The team believes that hardware biases could be potential explanations for discrepancies in COVID-19 outcomes and may have implications for the monitoring and treatment of other respiratory diseases. More studies are underway to determine the clinical consequences of this bias.

Source: Johns Hopkins University

2022-06-01 19:02:59

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