An inclusive pulse oximeter: Steps taken so far, what needs to be done

Key takeaways:

• Pulse oximeters are more effective in white patients than in Black patients.
• Those in health care need to question and challenge pulse oximeter manufacturers.

WASHINGTON — With the widespread use of oxygen saturation in medical practice, a pulse oximeter that works on all skin pigments is crucial, according to an American Thoracic Society International Conference presentation.

“[Oxygen saturation is] core to how we think about patients and how they are doing, how healthy they are, how sick they are, whether they are critically ill,” Thomas Valley, MD, MSc, David A. Spahlinger Endowed Assistant Professor in the division of pulmonary and critical care medicine at Michigan Medicine, said during the presentation. “When someone is in the ICU, one of our tenets is to maximize someone’s oxygen saturation.”

According to Valley, pulse oximeters also played a major role during the pandemic, which further demonstrates how significant they are in critical care.

“During COVID, we were telling everyone to go out and buy a pulse oximeter, and that’s how we decided whether someone was sick or not,” he said. “They’re everywhere, so it’s not surprising that we use oxygen saturation to make incredibly important decisions, [such as] whether someone should be taken into the hospital, whether someone is critically ill, whether they should receive mechanical ventilation, whether they should receive a lung transplant, whether they should receive ECMO.”

With all these examples of instances in which pulse oximeters are used, it is crucial that they work for patients of all races and ethnicities, but that is not the case. Valley said recent studies have shown that there is a racial bias with these devices. Compared with white patients, pulse oximeters are not as effective in Black patients.

“In particular, most of these studies show that measurements for Black patients are about three times more likely to miss hypoxemia,” Valley said.

There are also studies that have investigated the consequences of missing low oxygen levels in Black patients due to pulse oximeters, and Valley said these include less supplemental oxygen, delayed eligibility for lifesaving treatments, more failing organs and higher mortality odds.

When considering whether pulse oximeters are racist, Valley said no, but he believes they portray how some races tend to be more valued.

“Pulse oximeters aren’t racist,” he said. “I think they’re doing exactly what they were designed to do. They were designed to measure oxygen levels accurately, and they were calibrated to measure those oxygen levels in certain groups of people. ... But I think they do reflect how we value certain people in our society.”

Potential solutions

Valley continued by saying that there are five proposed solutions for addressing the poor performance of pulse oximeters for patients with darker skin pigmentation: taking account of patient symptoms, physical examinations, different locations for the pulse oximeter, obtaining more arterial blood gases and higher oxygen saturation. However, most of these are not foolproof, with Valley saying that the arterial blood gases solution “just trades one bias for another.”

“Now we’re subjecting certain groups of people to a painful invasive procedure that requires technical expertise,” he said.

In terms of the proposed use of higher oxygen saturation in Black patients, Valley said this finding was discovered in a single center study 30 years ago but nothing has changed in clinical practice.

Notably, for solutions to work, they have to be valued by many different people, Valley said. This includes journal editors, reviewers, investigators, teachers, students and readers.

“In order to disseminate this knowledge, we need to consider what we’re reading and what it means and consider the value that it is bringing to the table,” he said. “Certainly, when we were attempting to publish our paper, we ran through numerous barriers in trying to publish it. Several of which basically said this is impossible, there’s no way pulse oximeters could be racist. So, it takes a critical lens to get through those barriers.”

Progress made, future fight

When discussing progress on the issue of pulse oximeters, Valley highlighted the Anesthesiology and Respiratory Therapy Devices Panel of the FDA’s Medical Devices Advisory Committee that took place in November 2022, on which Healio previously reported. He also briefly noted calls to action on this issue by the National Health Service in the U.K. and major critical care societies.

Valley concluded his presentation by saying that those in health care need to question and challenge pulse oximeter manufacturers to achieve health equity.

“There is a device [designed amongst a diverse group of patients] that exists but pulse oximeter manufacturers [and] we as a society do not value the increased costs associated with that device, and so we have continued to use a device that doesn’t work as well for Black patients,” Valley said.

“Until we can make large-scale purchasing decisions that say you need to show us these devices work, we’re not going to be able to convince manufacturers of the importance in how much this matters to us,” he added. “I think ultimately, yes, pulse oximeter manufacturers need to develop better tools, but we’re complicit with this because we continue to use these tools without recognizing the impact on our patients.”