Pulse Oximetry

What is it and why you should have it during the pandemic

Photo by Olga Kononenko on Unsplash

In 2005, I was a family physician with chronic migraine. One weekend I had a migraine so bad that one of my partners put me in the hospital on a pain-relieving medication. At the time, we didn’t know that I was very sensitive to that medication and that I had obstructive sleep apnea which caused me to stop breathing when I slept. I was in a regular hospital room which meant that I didn’t have a heart monitor or a pulse oximeter to show the oxygen saturation level in my blood.

At about 2 am, a nurse came to check on me and found that I had quit breathing. She called a Code Blue, pushed Narcan into my iv, and I eventually woke up, but not before the Emergency Department physician, respiratory therapist, and entire Code Blue team had gathered around my bed and started an alarming number of tests. All for lack of pulse oximetry.

What is a pulse oximeter or pulse ox, as they’re called is a device that goes on the end of your finger (or your ear lobe or occasionally a toe) that measures the amount of oxygen that is bound to hemoglobin in the blood. The pulse ox uses infrared light absorption by the hemoglobin in the blood to calculate the oxygen saturation. Here’s a technical explanation of the science.

You generally want your pulse ox to measure around or above 90%. Most people have oxygen saturation above 95%. A pulse ox is a quick and easy check on breathing effectiveness. (There are plenty of caveats to pulse oximetry. Pulse oximetry is a helpful tool but doesn’t substitute for clinical impression.)

Pulse oximetry was developed in the 1980s. When I was in medical school in the early 90s, pulse oximeters were used in the ICUs and Emergency Department. They weren’t available on the regular medical and surgical floors. By the time I got into residency, there was a pulse ox on every unit. You wouldn’t have one on your finger the whole time you were there unless you were in ICU, but your nurse could come and check your blood oxygen level with your other vital signs.

When I was in practice, it was pretty much the same. I practiced in a rural hospital, but we were pretty up to date. We had ICU rooms and monitored rooms where the patient would have a pulse ox on all the time and the nurse could see the result at the nurses’ station. When I had my episode, I was considered low-risk, so I wasn’t in a monitored room and didn’t have a pulse ox on all the time. The nurse just checked it when they did their rounds.

Now, in almost every hospital, patients can have a pulse oximeter on a finger with a nurse monitoring in every room if they need it.

Times are changing, though. This technology that used to only be available in ICUs is now available for home use. I bought my pulse oximeter from a medical supply store for $30. It’s the same quality as the ones in the hospital.

Why do I have one? If anyone in our family gets Covid-19, this is a great way to help us decide if we need emergency medical care. My mother-in-law is 78 years old. If she’s coughing a lot and feels a bit short of breath, should she go to the emergency department? If her oxygen saturation is high and she otherwise looks good, then we can probably take care of her at home.

My parents have a pulse ox and when my mom had Covid-19, she would check her oxygen saturation when she got a bit short of breath. Earlier in 2020, she had a respiratory infection with mild shortness of breath and significant coughing and found the pulse ox helpful. When her saturation levels dropped into the low 90s after being in the high 90s, she sought medical care and found that she had pneumonia. She was treated with medication and breathing treatments at home.

With the pandemic going on, I recommend everyone spend the $30 and get a pulse ox. They’re easy to use. You just put it on your finger. (You can’t be wearing nail polish.) It reads out your heart rate and your oxygen saturation level. Check the instructions so that you know which is which.

If you’ve got respiratory symptoms with a pulse ox less than 90, you need to contact your medical professional. Remember that a pulse oximeter doesn’t substitute for medical advice. If you are still feeling very sick even with a normal oxygen saturation, you should seek out medical care. The pulse oximeter is just another tool in your arsenal to help you and your medical provider manage your health and medical care, especially during the pandemic.

I am a 50-something woman who is retired from the practice of medicine because of chronic migraine. I write about chronic illness, faith, and their intersection

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