The Issue with Pulse Oximeters
Pulse oximeters, widely used in healthcare facilities, are instrumental in monitoring heart rate and blood oxygen levels. These devices, however, have a flaw that can lead to serious consequences. They are known to provide inaccurate readings for individuals with dark skin, making it difficult to detect dangerously low oxygen levels. The US Food and Drug Administration (FDA) is actively addressing this issue by evaluating the performance of pulse oximeters on people with different skin tones. Engineers are also developing technological solutions, such as devices that can compensate for poor signal quality or darker skin tone.
Research Findings and FDA's Response
Research has demonstrated that darker pigmentation can affect how light is absorbed by the sensors in pulse oximeters, leading to inaccurate results. This inaccuracy could lead to delayed care or missed diagnoses. For instance, a report in the New England Journal of Medicine found that Black patients had nearly three times the frequency of undetected low blood oxygen levels that were not picked up by pulse oximetry as compared to White patients. The FDA issued a formal warning about pulse oximeters in February 2021, citing limitations and risks of inaccuracy, especially for patients with conditions such as COVID-19 who monitor their condition at home.
Improving Pulse Oximeter Trials
The FDA panel has recommended more diversity in pulse oximeter trials to address this issue. The agency is considering proposals to update clinical trials to include more diverse groups of people with at least 24 participants spanning the entire range of skin tones on the 10 shade Monk Skin Tone scale. Panel members unanimously agree that the current requirements for clinical trials are inadequate and that more diversity is needed. This Monk Skin Tone scale is suggested as a useful tool for evaluating the performance of pulse oximeters with different skin tones.
Technological Fixes and Innovations
Technological advancements are also being put in place to improve these devices. For instance, a device developed at Tufts University can detect poor signal quality and adjust the light transmission accordingly. This innovation aims to enhance the accuracy of pulse oximeters for all individuals, regardless of skin tone. The FDA is also considering new clinical trial requirements to ensure accuracy across all skin tones, including using the Monk Skin Tone (MST) scale and Individual Typology Angle (ITA) at the sensor site.
Despite these challenges, the potential benefits of pulse oximeters still outweigh their limitations. However, there is an urgent need to improve the technology to address health disparities. Improving the accuracy of these devices could lead to fairer health outcomes, particularly during the COVID-19 pandemic when pulse oximeters have been extensively used. The FDA's ongoing evaluation of pulse oximeters is a promising step towards addressing these disparities. It's crucial that patients, researchers, and medical device developers continue to provide insights to guide this process.