The FDA's Anesthesiology and Respiratory Therapy Devices Panel convened to address the longstanding issue of pulse oximeters providing less accurate readings for individuals with darker skin tones. The panel reviewed methodologies to enhance the evaluation of pulse oximeter accuracy across diverse patient populations, potentially impacting the future of premarket clinical trials and device labeling.
Addressing Racial Disparities in Pulse Oximetry
Research indicates that pulse oximeters, which estimate blood oxygen saturation using light beams, may yield inaccurate readings in individuals with darker skin pigmentation if not properly calibrated. This can lead to missed diagnoses of low blood oxygen levels, particularly critical during respiratory illnesses such as COVID-19. Dr. Jesse Ehrenfeld, president of the American Medical Association, noted that studies have shown pulse oximeters are three times more likely to provide misleading readings for patients with darker skin pigmentations.
Proposed Changes to Clinical Trial Standards
Currently, the FDA recommends that pulse oximeter developers include a range of skin pigmentations in their clinical studies. The panel is considering proposals to update these clinical trials to include at least 24 participants spanning the entire range of skin tones on the Monk Skin Tone scale, a 10-shade scale developed by Harvard's Dr. Ellis Monk. This is a significant increase from the previous requirement of just two darkly pigmented subjects or 15% of the study group, whichever is larger.
Dr. Jeffrey Feldman, a panel member from the American Society of Anesthesiologists, emphasized the need for greater diversity, stating, "There’s no question that more diversity needs to be a part of whatever new requirements that they would issue." He added that the prior requirements were inadequate to predict real-world performance.
Sample Size and Longitudinal Evaluation
Several panel members voiced concerns that even 24 participants might be insufficient to achieve adequate statistical power. Dr. Thomas Wiswell, a neonatologist, and Dr. Ben Saville, a biostatistician, both suggested that a larger sample size would be necessary to ensure the reliability of the results. Additionally, Dr. Tamorah Lewis, a physician scientist, proposed that clinical studies should evaluate pulse oximeter performance over time for different skin tones, assessing the consistency and reliability of readings.
Monk Skin Tone Scale and Practical Implementation
The panel largely agreed that using the Monk Skin Tone scale would be beneficial. Dr. Cheryl Gooden from Yale School of Medicine highlighted it as "the most diverse scale that we’ve discussed today." Dr. Monk presented his research to the panel, demonstrating how the scale can be used to evaluate pulse oximeter performance across various skin tones. The Monk Skin Tone scale has already been adopted by Google to improve representation in its products.
Implications for Over-the-Counter Devices
The FDA is also considering whether over-the-counter pulse oximeters should be held to the same standards as prescription devices. Panelists debated how to reflect this on device labeling, with some suggesting a clear warning label for devices that have not undergone rigorous testing. Others proposed keeping such devices behind the pharmacy counter to allow pharmacists to explain the limitations to consumers.
Industry Perspective
Major pulse oximeter manufacturers, including Medtronic and Masimo, have expressed support for many of the proposed changes, including the use of a validated scale like the MST and the recommended minimum sample sizes. However, they also raised questions about the specifics of non-disparate bias evaluation and performance thresholds. Dr. Sam Ajizian, chief medical officer of patient monitoring at Medtronic, cautioned against using pulse oximeter results alone as a threshold for making care decisions.
The Path Forward
While challenges remain in ensuring equitable performance of pulse oximeters, the FDA panel's recommendations represent a significant step toward addressing racial disparities in medical device accuracy. The ongoing evaluation aims to improve the quality of premarket studies and ultimately provide more reliable and inclusive healthcare for all patient groups.
