What is a pulse oximeter?

A pulse oximeter is a small, portable medical device that measures the oxygen saturation levels in the blood when it is clipped on a person’s finger, toe, or ear lobe. This non-invasive medical tool is a spot-check monitor that quickly determines how efficiently the blood from the heart and lungs is being sent to the various organs of the body.

What is a pulse oximeter?

A pulse oximeter measures two things:

  • Blood Oxygen Saturation (SpO2): The measurement that indicates what percentage of blood is saturated. To keep it simple, it is an estimation of the oxygen amount that is being carried by the red blood cells.
  • Pulse Rate: Pulse rate is nothing but the heart rate that indicates the number of times a heart beats per minute.

How does a pulse oximeter work?

A pulse oximeter works on the principle of spectrophotometry which deals with visible light. When the pulse oximeter is placed on the fingertip or toe or earlobe of the person, it beams multiple small rays of light that pass through the blood in that specific part of the body.

The light sensors in the pulse oximeter measure the number of blood cells that carry oxygen and those which do not. It is observed that the oxygenated blood is darker than the deoxygenated blood. Therefore, the highly sensitive light sensors in the pulse oximeter detect the variations of light absorption patterns between the oxygen-carrying blood and non-oxygen blood and translate into a reading.

Why does one need a pulse oximeter?

A pulse oximeter is usually used to check how efficiently one’s heart is pumping the oxygen through the body. Some patients are advised to use pulse oximeters in order to regularly monitor their blood oxygen saturation levels, which could often get affected by existing respiratory or cardiac issues. In such cases, one should keep a pulse oximeter handy to spot check the oxygen saturation levels, whenever necessary.

Some of the medical conditions that can affect blood oxygen saturation levels include:

  • Chronic Obstructive Pulmonary Disease (COPD)
  • Lung cancer
  • Asthma
  • Heart Attack
  • Congenital heart defects (birth defects)
  • Pneumonia
  • Anemia

How to use a pulse oximeter?

The pulse oximeter is used both for the ongoing monitoring of hospitalized patients and to take a single reading at the time of consultation. The steps involved during the procedure of using a pulse oximeter are as follows:

  • At first, the pulse oximeter is clipped on the person’s finger, toe, or earlobe. As it is a non-invasive test, no pricking is involved. But the person may feel slight pain or pinch due to clipping the device
  • Turn on the probe and within a few seconds, the device will collect accurate information and show readings of blood oxygen saturation levels and pulse rate.
  • Once the reading is noted, the probe can be removed and it will shut down automatically.
  • In some cases, the probe is left on for a certain period of time in which ongoing monitoring of oxygen saturation levels is required.

Understanding the readings of pulse oximeter

The pulse oximeters usually show the values of blood oxygen saturation levels as a percentage, represented by SpO2. While the pulse rate is displayed as a number ranging in between 60 and 100, which indicates a normal heartbeat.

A SpO2 reading ranging between 95% to 100% is considered normal, while anything less than 95% indicates underlying medical conditions that need to be evaluated immediately. The lower blood oxygen saturation levels might indicate the following health issues which need medical attention at the earliest:

  • Breathing difficulties
  • Lung infection
  • Blocked airways
  • Poor blood circulation

Tips to get accurate results on pulse oximeter

In general, the readings on the pulse oximeters are accurate. But, there are some factors that can affect the functioning of the device and result in errors or inappropriate readings. Here are a few things you should consider while using a pulse oximeter for accurate results:

  • Make sure to place the finger properly into the device
  • Sit still while taking the readings
  • Position the probe correctly
  • Remove any nail polish, tattoos or henna dye
  • Warm-up your fingers before starting with the test

What are the risks of using a pulse oximeter?

There are no real risks involved with using a pulse oximeter and it is considered safe. In some cases, the probe is fixed for continuous monitoring using an adhesive, which can irritate your skin. Finally, a pulse oximeter is a simple, non-invasive, and reliable medical device that gives accurate readings of blood oxygen saturation levels with no risks.



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