Ein pulse oximeter as an early warning indicator for corona infection: This steep thesis is currently circulating in the socially calling networks and on YouTube. If you use such a device and measure it regularly, you will learn about your infection early, it is said. One of the leading manufacturers of these devices already has delivery problems.
What is behind it? A pulse oximeter is a small clip that is placed on the finger like a clothespin. It measures the arterial oxygen saturation of the blood and the pulse using two light beams of different wavelengths. The finger oximeters cost between 25 and 200 euros. Oxygen saturation indicates the percentage of hemoglobin in arterial blood that is oxygenated and saturated.
The small medical measuring devices may have been seen in the hospital, they are also used in medical practices and by emergency services. Some sports watches from Garmin, Withings and Fitbit are also able to measure oxygen saturation with their optical sensors on the back.
Sports watches offer this functionality for one reason in particular: as a warning of altitude sickness in the high mountains. The air pressure drops with the altitude, so there is less oxygen in the air we breathe. The body has to make more red blood cells with oxygenated hemoglobin, and that takes time. Even well trained mountaineers can get altitude sick if they do not take regular breaks to acclimatize. Here the measurement of the oxygen saturation is helpful.
Pulse oximeters for finger measurements are recommended by doctors for lung diseases or asthma. The oxygen saturation of healthy people is over 90 percent. With Covid-19 infection, oxygen saturation is just one of many vital signs that is monitored in affected patients. Too little oxygen saturation is not an indication of infection, and vice versa, not every infected person has too little oxygen saturation. Although causality cannot be assumed, demand is exploding, as a look at the corresponding Google searches with Google Trends shows. Accordingly, interest has skyrocketed in Europe and America since mid-February.