Are Fingertip Oximeters Accurate on Dark Skin?

I just saw a post from TikTok school nurse who discovered that fingertip oxygen monitors (pulse ox) aren't accurate on dark skin. 

I know school nurse aren't experts in all areas, and my kid's school nurses were always frantic treating concussions, diabetes, broken bones, stomach flu, pink eye, lice, etc.

So it's no wonder this nurse didn't hear about the problem with wrong readings on oxygen monitors.  

Pandemic discovery in 2020  

The finding about the problem with finger tip oxygen monitors was discovered during the pandemic in spring of 2020.  

Doctors in a Detroit hospital in Ann Arbor noticed that their patients with dark skin seemed to have higher oxygen levels that didn't match the patient's symptoms. 

And that the oxygen level (pulse ox) didn't match the oxygen level during a blood draw from the artery (this is different from when they draw blood from a vein.) 

An arterial blood gas (ABG) draws blood from an artery to check oxygen, carbon dioxide and other levels in the blood. It's important because low oxygen levels can damage organs, including your brain and heart.  

The oxygen level and blood gas didn't match  

The ER doctor started to keep track of the mismatches between oxygen and blood samples from a patient's artery.  

He noticed the oxygen level was wrong more often in people with dark colored skin. In fact, it was wrong 3 times as often in patients with dark skin than in people with lighter skin.

In an article about the issue, they said that Dr. Michael Sjoding  

"......suspects the reason behind this is that the color of light used in pulse oximeters can be absorbed by skin pigment."

The article says people should pay attention to shortness of breath rather than what the pulse ox says. 

Symptoms are just as important as an oxygen level 

My friend has been a respiratory therapist (RT) for over 20 years and once told me that she's had to intubate patients with an oxygen level of 95. Yes, 95! She stressed how important it is to pay attention to your symptoms, and not just your oxygen level. 

She said she has noticed one thing during her long career as an RT. Some people with asthma are "notorious compensators." Meaning their oxygen level may not be low, but the patient's symptoms show they are seriously ill.  

That's the same thing my asthma doctor taught me when my kids were little. He always said a fingertip pulse oximeter is ONE tool to use when doctors are trying to assess how sick a patient is. But - it's just as important to look at symptoms.  

3 part podcast 

If you are an asthma nerd like me, you can listen to a 3 part podcast about "Racial Bias and Pulse Oximeters" from Johns Hopkins Bloomberg School of Public Health. 

It's worth a listen!