Get one if you can.
A veteran ER doctor, an expert on ventilator intubation, writes in a letter to the NY Times that these small, inexpensive devices offer a better path forward to get ahead of the the Covid-19 pandemic than widespread testing does.
Dr. Richard Levitan worked for 10 days at New York’s Bellevue ER and observed at first hand how the pneumonia caused by Covid-19 behaves differently than the lung problems that doctors typically encounter. He says the Covid pneumonia results in “silent hypoxia.” Levels of oxygen in the blood begin dropping, but the infected person feels no shortness of breath or difficulty in getting enough air — because the body is still able to expel CO2. It is the buildup of this waste gas in the lungs that triggers the gasping, elevated heart rate, and sense of shortness of breath common in ordinary pneumonias.
By the time the infected person feels short of breath, dangerously low blood oxygen levels might already be causing damage across the body’s critical organs.
This analysis reinforces what front-line doctors have been reporting since March, as I sketched out in this blog post from April 14. (In fact Dr. Levitan is one of the physicians quoted in the NY Times piece linked there.) SARS-CoV-2 infected people often present more like sufferers of high-altitude sickness than like those afflicted with Acute Respiratory Distress Syndrome.
The simplest pulse oximeters, made for home use, report blood oxygen saturation level and heart rate. They clip onto a finger and produce a reading in seconds. They cost around $20 — or at least they did before the pandemic took hold. Many online sellers are reporting out of stock and those vendors that let you search local physical inventory — CVS, Walgreen’s — often report the same. You might still be able to find one online, possibly after some diligent searching; my wife just ordered one for us that should arrive in under two weeks.
A pulse oximeter will alert you if your blood oxygen level starts to drop. This would be the time to call your doctor, not after you develop shortness of breath, by which point significant damage might already have been inflicted on your body — and you may require a ventilator to save your life.
Dr. Levitan summarizes:
My gosh that is brilliant! If fact, just yesterday my husband seemed a little short of breath when he came upstairs to visit me in my sewing room, where I live these days. (Mask maker mask maker! Make me a mask! )
He does have a history of heart failure and strokes. I ran downstairs and started rummaging around in drawers and sure enough I found it!! My handy dandy little pulse oximiter. Battery dead. New batteries. Bingo! His oxygen saturation was 96%. Yay. Perfect. Mine was 97%. I love that thing!
Here’s a next-day follow-up: some reasons why the majority of healthy people maybe shouldn’t be looking at their oxygen levels multiple times per day. The reasons boil down to: consumer- not medical-grade instruments, the possibility of misinterpreting readings, and boosting anxiety with constant checking.