How to purchase the right oximeter and take correct readings: A doctor writes

The oximeter, once a rarely known about device that was used only in hospitals, has now become a household item since the coronavirus pandemic began. To safeguard COVID-19 patients from deteriorating health, doctors suggest monitoring oxygen saturation (SPO2) levels frequently. The pulse oximeter is a small, clip-like device that measures the heart rate and the SPO2 level in the blood in a non-invasive and painless way.

For a person who has tested positive for coronavirus, oxygen levels are key indicators to understand whether the infection has spread to the lungs. Especially among people who have mild symptoms or are asymptomatic, this device helps to track the severity of infection. Pulse oximeter is typically a fairly accurate test, with a provision for an error margin of 2%. Therefore, oximeters have become a must-have device during the pandemic to know the condition of your lungs.

With increased demand for oximeters, there is an influx of multiple types of devices in the market, which is making it difficult for people to choose. Do we know if the product we are using is calibrated correctly and working properly? A faulty oximeter may provide flawed readings, which may in some cases lead to emergency situations as people are increasingly dependent on oximeters. In many cases, these variations may go unnoticed and people may end up in the emergency room.

The lack of knowledge about the device and the variety of choices have now left people more confused regarding the purchase of oximeters. There are reports of oximeters showing SPO2 levels of more than 100, which clearly indicates that they are faulty, because the SPO2 percentage has to be within 100. Therefore, it is important to look for genuine brands and check the device before buying one. Let’s understand how an oximeter works, how to take readings and how to identify faulty readings.

While checking the oximeter reading, one has to give importance not only to the numbers but also the waveform displayed. The waveform of a healthy person will be pulsed, i.e., with every heartbeat there should be a spike to reflect blood flow. This gives more clarity about the performance of the device. It is not only the device one should be careful about but using the device properly and noting the reading in the right way is crucial to understand a person’s true health condition. 

What to look for while buying oximeter

There are three different varieties of oximeter – finger pulse oximeter, hand-held oximeter and fetal pulse oximeter. While the finger oximeter is generally used at home, others are used in hospitals. It is important to buy the right type of device to avoid unnecessary panic. While buying an oximeter, look for the following features:

> Clear and bright display

> Made of durable material

> Provides accurate readings

> FDA, RoHS or CE certification

How to use the oximeter properly?

> Rest for 10-15 minutes before taking readings

> Remove nail polish before checking and ensure finger is dry

> Rest one hand on chest and hold still

> Place the oximeter on the middle or index finger of the other hand

> Rest the finger on the thigh and not the chest

> Keep the finger in the same place till the reading is stable

> Register the highest result once the reading stabilises

> Identify the reading carefully

> Start recording from the baseline and record thrice a day unless you notice any changes in your health

> Consult a medical professional in case of breathlessness or dip in oxygen levels to 95% or less

If you have tested positive for coronavirus, it is important to monitor the blood oxygen level. Make the right decision while buying the oximeter and do not fall for discounts or sales.

Dr Chinnadurai R is Lead Consultant – Critical Care at Aster RV Hospital, Bengaluru.