Pulse Oximeters Once Again in the Spotlight at FDA

— Advisory panel to discuss how to improve device accuracy for patients with darker skin

by Joyce Frieden, Washington Editor, �ڴ�Ů�� January 31, 2024

FDA ADCOMM Pulse oximeters over a photo of one on a man’s finger.

Improving the accuracy of pulse oximeters, especially in patients with darker skin pigments, will be the focus at of the FDA's Anesthesiology and Respiratory Therapy Devices Panel, part of its Medical Devices Advisory Committee.

"Although pulse oximeters provide clinical benefit for patients through the non-invasive estimation of blood oxygen saturation, the risks associated with inaccurate pulse oximeter readings must be well understood," FDA staff wrote in a for the panel.

"The COVID-19 pandemic, which resulted in increased use of pulse oximeters in the hospital and home settings, highlighted the limitations and risks associated with this technology, particularly in patients with darker skin pigmentation," they added. "Clinicians recommending the use of pulse oximeters to patients to monitor health conditions at home, and consumers using OTC [over-the-counter] pulse oximeters for medical purposes, should be aware of these limitations to avoid delays in treatment and adverse patient outcomes."

"After hearing from patients, regulators, researchers, and industry, the committee will be asked to discuss the proposed approach to improve the quality of premarket studies and associated methods used to evaluate the performance of pulse oximeters for medical purposes submitted for premarket review, taking into consideration a patient's skin pigmentation, and patient-reported race and ethnicity," the briefing document continued. "The committee will discuss the type and amount of data that should be provided by manufacturers to FDA to evaluate the performance of pulse oximeters submitted for premarket review, including prescription and over-the-counter indications, for labeling considerations, and ways to help guide other regulatory actions as needed."

The committee meeting builds on previous work the FDA has done on this issue. At a November 2022 meeting of the same advisory panel, members agreed that pulse oximeters are less accurate in patients with darker skin, and that the FDA should notify patients and providers about the issue and recommend that manufacturers correct the discrepancy.

"I think the clinical evidence does demonstrate disparate performance in patients with darker skin pigmentation; we saw a lot of studies and everything pointed to the same," then-Panel Chair Steve Nathan, MD, said at that meeting. "In my mind, I think the evidence we saw was quite clear."

The agency is adding a new wrinkle at this meeting: FDA officials are considering updating their 2013 guidance to pulse oximeter manufacturers, and as part of that effort, they want the panel to weigh in on the design of a premarket clinical trial that pulse oximeter manufacturers could perform. The trial would be designed "to improve the quality of premarket studies to evaluate the performance of pulse oximeters, taking into consideration a patient's skin pigmentation, and patient-reported race and ethnicity."

FDA staff listed "key elements" of its clinical trial proposal:

Inclusion of at least 24 participants that span the entire Monk Skin Tone (MST) scale. The MST has been validated to capture race and ethnicity diversity in pigmentations within the U.S. This will improve generalizability of study results.
An initial assessment of skin pigmentation with MST scale followed with an objective pigmentation measurement -- Individual Typology Angle -- at the sensor site.

The agency is on both the approach being proposed to measure pigmentation, as well as the trial size, and whether both of those elements will provide enough diversity "with respect to race, ethnicity, and skin pigmentation." There are no questions for the panel to vote on at the meeting.

In the briefing document, FDA staff summarized recent studies on the topic that they had found through a PubMed search conducted in December 2023. The search used the strategy "pulse oxim* AND (race OR racial OR pigment)" to identify clinical studies published between Aug. 9, 2022 and Dec. 6, 2023, "pertaining to the topic of pulse oximetry performance in individuals with darker skin pigmentation," the briefing document noted, adding that additional articles were identified via cross-referencing and review articles.

They wound up with a total of 46 articles: 28 from a 2022 literature assessment and 18 new ones from the recent search. Of those, seven were literature reviews, which the staff summarized. of 34 prospective and retrospective studies showed that "there is growing evidence that pulse oximeters are less accurate in dark-skinned individuals at lower saturation (<80%) resulting in overestimations," and also that "a more accurate method for classifying the research subjects into categories by degree of skin pigmentation should be employed in these studies."

of 32 studies concluded that "pulse oximetry may overestimate blood oxygen saturation levels for people with dark skin in hospital settings compared with gold standard SaO₂ [arterial oxygen saturation] measures. The evidence for the measurement bias identified for other levels of skin pigmentation or ethnicities is more uncertain."

The Friday meeting is scheduled to run for 9.5 hours, including a 30-minute lunch break. The FDA doesn't have to follow the advice of its advisory committees, but it often does.

Joyce Frieden oversees �ڴ�Ů��’s Washington coverage, including stories about Congress, the White House, the Supreme Court, healthcare trade associations, and federal agencies. She has 35 years of experience covering health policy.