The Final Say on Pulse Oximeters

Thanks to Apple, the once-buzzy medical devices are back in the news

Photo by Syed Ali on Unsplash

Remember pulse oximeters? In the early days of the pandemic, the small, clothespin-like devices, used to measure the amount of oxygen in the blood, had a brief moment in the spotlight thanks in part to a widely read op-ed in the New York Times suggesting they could help identify undetected cases of Covid-19. Now, they’re back in the news after Apple announced that its new Apple Watch Series 6 will have a pulse oximeter.

But despite the increasing availability of these devices, their usefulness for the average healthy person during the pandemic remains debatable.

The Times op-ed, written by emergency room physician Richard Levitan, MD in mid-April, explained that pulse oximeters could be useful in detecting “silent hypoxia” — the dangerously low oxygen levels that sometimes accompanied pneumonia caused by Covid-19. Levitan said that widespread pulse oximetry could “provide an early warning system for the kinds of breathing problems associated with Covid pneumonia.” Notably, he didn’t say that the devices could detect Covid-19 directly. Nevertheless, pulse oximeters began selling out at stores.

As I previously wrote on the Coronavirus Blog, other experts have argued that these devices aren’t necessary for people who are healthy and have no Covid-19 symptoms. Albert Rizzo, MD, chief medical officer for the American Lung Association, says it’s important to remember that the people with Covid-19 that Levitan described didn’t show up to the hospital with a low pulse oximetry reading as their major symptom; they had cough, fatigue, and low-grade fever, and low oxygen was detected later. “It wasn’t like the pulse ox was giving them early warning about Covid-19,” he tells the Coronavirus Blog.

He says the devices are useful for doctors to help monitor patients with symptoms of Covid-19 that are too mild to warrant hospitalization. It’s now known that a fair number of patients develop a severe complication of Covid-19 where their blood vessels are affected, causing a precipitous drop in oxygen levels, and pulse oximeters can identify when these people need to go to the hospital.