How To Correctly Use A Pulse Oximeter

How To Correctly Use A Pulse Oximeter

The Pulse Oximeter has recently come into prominence with it being widely used in hospitals as well as homes to check the level of oxygen in a person’s blood. This has helped many people with low oxygen to seek timely help from medical professionals, almost helping to save their lives which COVID 19 has endangered over time. While the technology of pulse oximeters has been around and used quite rampantly in hospitals previously, there are still some myths and reservations which are attached to it. So in this article, we will explain to you what a pulse oximeter does, how it functions, how to use it and put it on in a correct way and at the same time, debunk some common myths related to the practice of pulse oximetry.

So let us start by understanding what exactly is a pulse oximeter and the function which it tends to perform. This is a rapid portable non-invasive handheld device which essentially helps to give the level of oxygen which is present in a person’s bloodstream and is completely painless. It also shows the pulse rate of a person. It is quite helpful in monitoring and determining any instant regressions in a person’s health. The readings which are usually available on a pulse oximeter are SpO2 which is the oxygen saturation in the blood, the pulse rate and perfusion index (PI) which is the ratio of dynamic blood flow to the static blood in the peripheral tissue.


How Does A Pulse Oximeter Work?

A typical pulse oximeter uses an electronic processor and a pair of small light-emitting diodes (LEDs) facing a photodiode and the finger is inserted in between them both (refer to the image below for better clarity). The measurements are given by passing light through the fingertip of the patient, to which the pulse oximeter clips on. One LED is red, with a wavelength of 660 nm, and the other is infrared with a wavelength of 940 nm.

As soon as the fingertip is inserted inside the device, the LEDs start to emit the red and infrared lights through the person’s finger. As the photodiode receives them, the electronic processor calculates the pulse rate, the SpO2 and the PI% data simultaneously, flashing the readings on the exterior electronic screen to be used by a medical professional or on a personal level.

How To Use A Pulse Oximeter In A Proper Way?

Now that we have seen what a pulse oximeter is, the functions it performs as well as the scientific way in which it works, let us understand how to use it properly so that it can give correct readings. The correct steps to use a pulse oximeter are listed below:

1. Make sure to stay calm and rest up at least for ten minutes before putting on the device

2. Make it a point to be in a sitting position while measuring the oxygen level. You should sit straight and keep your finger with the device clipped on at your heart level

3. Clip on the pulse oximeter and sit still

4. Make sure that the device is touching your skin and not just your nails

5. The device works being clipped on either of your hands but needs to be on your index finger or your middle finger

6. Wait for a bit till the reading more or less stabilises. Once it does, note it down and consider the highest reading

7. You can keep a record of your oxygen levels and check them thrice a day to stay on top of your health

What Do These Measurements Mean?

So now that you have checked your vitals using a pulse oximeter and have readings, what do they actually mean and are they normal? A normal SpO2 reading ranges from 94 to 100. If your oxygen in the blood is any lower than that, it may mean that the required oxygen is not reaching all your tissues in a way that they can function properly. You will probably require supplemental oxygen in such a case and hence should immediately contact your doctor if such a situation arises. The pulse rate normally ranges from 60 to 125. The PI% should ideally lie between 0.2% to 20%.

Debunking Some Myths Related To Pulse Oximeters

Now to come to the common myths which are associated with pulse oximeters and try to debunk them while explaining the scientific logic behind it.

- My Pulse Oximeter Is Showing Readings Of Pencils And Other Items:
A common complaint that people have with their pulse oximeters is that they show the readings of a pencil, pin, sketch pen or any other unusual item as well. While this may occur occasionally, it does not mean that your pulse oximeter is faulty or that it does not work. It is completely possible that the oximeter gets tricked with the insertion of pens as it shines a light through the item. If the processor does receive some light from the other end, a reading is imminent in such a case as the device believes it to be a finger.

The item may also diffuse some light which can give a false impression to the device about the presence of a human pulse leading to a reading. But it will automatically switch off after a minute once it realises that no actual blood is flowing through the item. The oximeter is designed in a way to be able to show readings even in extreme conditions and unusual cases, hence this case is quite plausible.

- They Are A Scam
Another myth that pulse oximeters are afflicted with is that they are a scam and they do not work. This is completely baseless as these devices help to give largely accurate readings if they are used in a proper way. These are also recommended by medical professionals and have been done so after rigorous clinical testing over time.

- If The Readings Fluctuate, The Pulse Oximeter Is Faulty:
The pulse oximeter works on the principle of taking multiple readings across small intervals of time to reach a fairly accurate result. But it is advised that the highest reading should be recorded and considered once it stabilises after some time. It is also important to note that the reading which is shown by the device is an estimate and should hence be treated as one and not as a rigid infallible number.

- They Detect COVID 19:
The pulse oximeter can only tell you about the level of oxygen in your blood among other readings, but it is in no way an indicator that helps you to determine if you have COVID or not as the low SpO2 can also be due to other health problems. Hence it is advised to discuss your reading with your medical professional and get a test done to know if you indeed have Coronavirus or not.

Now that you have finished reading this article, you know all that you need to know about pulse oximeters and how they are largely accurate and completely safe to use. Source:

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