Coronavirus: What is a pulse oximeter and how to use it?
Coronavirus: What is a pulse oximeter and how to use it?
AFP File Photo

As COVID-19 started taking over the world, a small medical device - pulse oximeter started gaining attention. The device is used to check blood oxygen levels.

Pulse oximeter is part of a larger screening and testing process of COVID-19 patients but it just indicates the oxygen level and cannot detect the disease on its own.

In a video interaction with the Health Minister and Health Secretary of the States on April 24, Union Health Minister Dr. Harsh Vardhan had said that the portable pulse oximeter can help in early diagnosis of the corona patients which can help to curb the mortality rate due to COVID-19.

According to PTI, Delhi Chief Minister Arvind Kejriwal in June, announced that his government will give pulse oximeters to the COVID-19 patients under home isolation in the city and said the number of coronavirus tests has increased by three times in the national capital.

A pulse oximeter is a small clip-like device that attaches to a body part like a finger, earlobe or toes. It helps in detecting hypoxia, a condition in which the body is deprived of adequate oxygen supply.

The process is easy and painless and indicates measure of how well oxygen is being sent to parts of your body furthest from your heart, such as the arms and legs.

How does a pulse oximeter work?

A pulse oximeter comes either as a small unit with a built-in finger/toe clip, or a small handheld device that can attach or be applied to your finger, toe or earlobe.

The small unit is less expensive and more practical for home use. Beams of light from the device pass through the blood in your finger (earlobe or toe) to measure your oxygen. You will not feel this happen.

The beams of light are “read” to calculate the percentage of your blood that is carrying oxygen. It also provides a reading of your heart rate (pulse).

To make sure the oximeter is giving you a good reading, count your pulse for one minute and compare the number you get to the pulse number on the oximeter. If they are the same, you are getting a good signal.

This picture shows a pulse oximeter. The screen shows that the Sp02 is 98% and the pulse rate is 72 beats per minute.

Screen of a pulse oximeter.
Screen of a pulse oximeter.

Steps to use a pulse oximeter?

  • Clip the pulse oximeter on a finger

  • The oximeter is supplied with a finger probe

  • For some oximeters ear probes are also available

  • Put the body part directly under the light

  • Turn on the probe

  • Allow several seconds for the pulse oximeter to detect the pulse and calculate the oxygen saturation

  • Look for the displayed pulse indicator that shows that the machine has detected a pulse

  • Without a pulse signal, any readings are meaningless

  • Once the unit has detected a good pulse, the oxygen saturation and pulse rate will be displayed

  • After the test is over and you have your results

  • Take off the probe and it will shut down automatically

Normal SpO2 is 95% or above. Any count under 95 shows a problem and that is when you have to consult a medical practitioner.

SpO2 of < 90% is a clinical emergency and should be treated urgently.

Factors that might stop a pulse oximeter reading accurately:

• Nail paint or pigment on finger

• Patient's movement

Disclaimer: Tips and suggestions mentioned in the article are for general information purpose only and should not be construed as professional medical advice.

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