If you've ever been to a hospital, you've likely come across a pulse oximeter before. It's the little device they put on your finger with the red light.
It's a non-invasive, pain-free way to measure oxygen in a person's blood, and it took on critical importance during the COVID-19 pandemic as respiratory distress was a key feature.
But, research says it has a fatal flaw: Pulse oximetry doesn't work as well with darker skin.
As we prepare for an increase in COVID, flu and RSV, pulse oximetry and its limitations could move back into the spotlight.
"I use it all the time to tell me how someone's oxygen levels are, whether we need to give them more oxygen, whether we need to bring them into the ICU," Dr. Thomas Valley, a U-M Critical Care Pulmonologist, said.
The problem, Valley said, is anything that blocks light from the pulse oximeter can make the device show an artificially high blood oxygen reading. And that can include darker skin.
"So that means a pulse oximeter is telling us that someone's oxygen level is 94%, when in actuality might be 87%," he said.
That's a value when doctors would typically provide support. Valley is co-author of a report that finds Black patients are three times more likely to have a low oxygen level missed by pulse oximeters. Valley says those misses are matter of life and death.
"When we made decisions to put someone on a breathing machine, it was based on someone's oxygen levels being low and these were based on pulse oximeter values," he said.
He says the result is delayed treatment, greater risk for organ failure and greater risk of dying. I took an at-home pulse oximeter out on the streets of metro Detroit.
"Of course, that’s a concern. Medical devices that do not work properly with, let's just say, our people? It's bad," Will Ewing of Southfield said.
"Especially considering it's been 30 years. Technology is in existence, and nothing's been improved about it. It's important that everybody gets the same health care," Holden DeHaan said.
This issue was first highlighted in 1990. It is still an issue today.
Valley says the other way to measure blood oxygenation is a more invasive, more painful arterial blood sample which may require an ER visit to find someone with the needed skills. It’s a barrier to effective care.
"Until we have pulse oximeters that work accurately for all people, we are disadvantaging people of color," he said.
Just last month, the American Medical Association adopted new policies calling for the Food and Drug Administration to ensure pulse oximeters provide accurate and reliable readings for patients with diverse degrees of skin pigmentation, and that health care providers are aware of their limitations.
I reached out Medtronic the largest medical device company in the world. They released this statement:
“Our pulse oximetry devices meet and exceed current FDA requirements and we stand behind their safety and efficacy.
The effect of skin pigmentation on Nellcor pulse oximeter performance has been presented in our own retrospective analysis, and in independent lab research at the November FDA Advisory Committee on Pulse Oximetry. The bias across all pigmentation levels is small, and not clinically significant.”
They go on to say that more needs to be done to improve accuracy for patients with darker skin tones and this can be done with innovation, education and standardization across the industry
