What is an oximeter and what is it for (also for Covid-19)

The oximeter measures the level of oxygenation in the blood and could help doctors understand if a patient is developing pneumonia even from a distance

(photo: Getty Images) How a thermometer helps us to understand when the body temperature it's too high, so an oximeter could tell us if we're developing pneumonia. A very useful tool these days, said Franco Locatelli, the president of the superior health council, who announces his intention to provide them to general practitioners and patients in home quarantine.

What is 'is the pulse oximeter

If you have never worn it for sure you have at least seen one in some movie or TV series. The oximeter is nothing more than that clip that is applied to a finger and that thanks to infrared rays is able to detect the level of oxygen in the blood. More precisely, it indicates the percentage of arterial hemoglobin saturation, and also measures the heart rate.

The clip, in reality, is only the probe, while another component of the instrument is the data processing unit, which it collects information, processes it - in fact - and returns it as a numerical value on a monitor. In the most recent models, the probe and the computer are combined, which makes them even easier to use and manage, even at home.

How it works

The operation of the oximeter is based on the different light radiation absorption properties of oxygen-bound hemoglobin and free hemoglobin. The first, also called oxyhemoglobin, absorbs in the infrared spectrum, while the second in the red.

Two diodes that emit light are positioned on a branch of the clip on the pulse oximeter probe (one in red, at 660 nanometers, and one in infrared, at 940 nanometers), on the other a sensor. When the oximeter is turned on, the light emitted by the diodes passes through the organic tissues and is recaptured by the sensor: based on the difference between the light emitted and that recorded, the computer obtains the percentage of hemoglobin linked to oxygen. Under normal conditions, this value is greater than 95%.

Oxygen saturation

When the number marked by the oximeter is less than 95%, you are in hypoxemia, which depending on the degree it is defined as mild (91-94%), moderate (86-90%) and severe (<85%). This condition may indicate a problem with the respiratory function and a potential risk to the health of the person, for example an ongoing pneumonia, such as the one that can develop if you contract Covid-19.

Home monitoring and remote diagnosis

According to experts these days, having an oximeter at home wouldn't be a bad idea. The tool is relatively cheap and easy to use even without medical support (just position it correctly and then everything is automated), and patient monitoring can provide important information in a timely manner: if the saturation drops, contact your doctor who will give instructions. on how to proceed, referring to hospitals (who are already suffering the impact of the second wave of coronavirus) who need it.