According to a new study, blood oxygen monitoring showed that the blood oxygen levels of hospitalized Asian, African and Hispanic covid-19 patients were higher than the actual levels. Blood oxygen level is an important indicator to measure how serious a person's covid-19 condition is and what kind of drug treatment they are eligible to receive - and this overestimation means that African American and Hispanic patients need more time to get the necessary treatment**
Pulse oximeter is a standard method for measuring blood oxygen in clinics and hospitals. Its working principle is to send red and infrared light through the fingertips and measure the amount reflected. Hemoglobin is a protein in the blood that carries oxygen. When it carries oxygen, it absorbs more infrared light. Over the years, research has shown that these devices are not ideal for people with darker skin.
In Journal of the American Medical Association, a research team investigated covid-19 patients in Johns Hopkins health system from March 2020 to November 2021. More than 1200 patients had their blood oxygen levels checked by pulse oximetry and more accurate blood tests. In about 30% of Asian, African and Hispanic patients, blood tests showed low oxygen levels when the pulse oximeter showed normal oxygen levels. Only 17% of white patients had this condition.
In a large group of more than 6600 patients, the team found that 1903 patients' models showed that their blood oxygen levels would drop before the pulse oximeter display. In this group, African American and Hispanic patients are more likely to delay treatment, such as redcivir (most hospitals only use it for patients with blood oxygen levels below 94%) or dexamethasone (most hospitals only use it for patients with supplemental oxygen).
In this group, 451 patients were never marked as eligible for treatment. More than half of these patients are of African descent. It took about an hour more for African American patients to be marked as eligible than white patients.
Other studies in the past few years have reached similar conclusions. For example, a study published in november2021 also showed that in hospitals, the difference between blood oxygen levels measured by blood tests and pulse oximetry in non white patients was more likely to occur than in white patients. Patients with this gap are more likely to have organ problems and die in hospital. The US Food and Drug Administration warned in February 2021 that the reading of pulse oximeter has "limitations", and skin color will affect the reading.
However, despite sufficient evidence of deficiencies, no major measures have been taken to correct bias, The researchers wrote in an editorial accompanying the new study: "Hospitals and doctors continue to purchase and use these devices, although they are inaccurate for non white patients. This is not an easy problem to solve, and the pulse oximeter is generally an inaccurate measurement of oxygen in the blood. However, hospitals and regulatory agencies should promote that only devices with different skin colors are allowed to have the same performance, and doctors can adjust their treatment methods to recognize the potential of non white patients In error. "
They wrote: "although the measurement error of the equipment is real and based solely on optical principles, it is a human decision not to make any decision on the faulty equipment, and it is a decision that can and should be corrected."