The “Super Trustable” Pulse Oximeter

The device above is a pulse oximeter that has been an essential tool for medical professionals. But according to multiple studies, the pulse oximeter may not work well for patients with dark skin. 

Pulse oximeters are clamp-like devices that can be attached to a patient’s finger, monitoring the amount of oxygen in their blood. This is a useful tool that is needed during the coronavirus pandemic. Covid-19, a respiratory illness, attacks the lungs first. Low oxygen levels in a patient’s blood and indicate that a patient may be deteriorating in health. According to CNN, CDC data shows Black, Latino and Native Americans are four times more likely to be hospitalized with Covid-19 than others.

The usage of pulse oximeters have increased during the pandemic, but are presenting inaccurate results, the US Food and Drug Administration stated on Friday. A few days ago, the US Centers for Disease Control and Prevention also cautioned doctors and nurses that the accuracy of the data released from the pulse oximeters may be affected by skin pigmentation. “While pulse oximeters may be useful for estimating blood oxygen levels, these devices have limitations that can result in inaccurate readings,” Dr. William Maisel, director of the Office of Product Evaluation and Quality in the FDA’s Center for Devices and Radiological Health, said in a statement. 

Because the frequencies of misleading number readings were high, researchers found how often pulse oximeters misread the oxygen levels. According to CNN, in White patients, the pulse oximeter gave a misleading number 3.6% of the time. In Black patients, it was 11.7% of the time. Being approximately three times more misreads, this study suggests that one in every ten black patients may get misleading results. 

A simple explanation follows for why there are numerous misreadings. The pulse oximeter works by two types of red light through a patient’s finger. On the other end of the device, it detects the color of a patient’s blood; if the blood is bright red, the blood is highly oxygenated, while purple or blue blood is less. The pigmentation of a dark skinned patient can affect how the light is absorbed. Dr. Michelle Ng Gong states that experienced physicians do not rely on pulse oximeters alone to decide a patient’s treatment. She continues that the pulse oximeter is a tool, and as a tool, doctors need to be able to use it properly in the context of other information. On the other hand, Dr. Gong says, pulse oximeters may hold more weight during a pandemic when hospitals are overwhelmed and doctors do not have enough time to check on every individual. 

The findings about the pulse oximeter have also been noticed back in the 1990s. Moran-Thomas suggested that there was a problem with pulse oximeters and darker-skinned patients back then. Another study in 2005 done by San Francisco’s Hypoxia Lab found three different models of pulse oximeters misread oxygen levels in darker skinned patients. A following study they did in 2007 resulting with similar conclusions.

Categories: Clinical, Tech&Innovation