What is Pulse Oximetry?

Pulse oximetry is a term often referenced in online and news media in relation to the recent pandemic. What is it?

Pulse oximetry is a medical procedure that uses non-invasive and painless methods to measure the level of oxygen saturation in a person’s blood.

The measure of oxygen saturation is important in assessing lung function. During the inhalation process, oxygen is transferred from the lungs into capillaries, which are small blood vessels. Capillaries transport oxygenated blood back towards the heart, which subsequently distributes it throughout the body via arteries.

For organs to function properly, a continuous supply of oxygen is required. Impaired lung capacity can result in a decrease of blood oxygen saturation, which may pose a risk to our organs. The use of a pulse oximeter can promptly identify a decrease in oxygen saturation, indicating the necessity for medical attention.

Measurement of blood oxygen saturation through pulse oximetry is a common practice during medical procedures or physical examinations. The popularity of at-home pulse oximeters has increased due to the spread of the recent virus pandemic. Some individuals have purchased these devices to monitor their blood oxygen levels out of concern for contracting the virus or if they suspect they have it.

According to Dr. Denyse Lutchmansingh, a pulmonologist at Yale Medicine, it is important to note that changes in pulse oximetry may not always be associated with respiratory viruses. Cardiovascular conditions can affect the lungs and cause low readings. Therefore, it is advisable to consult a doctor if readings remain consistently low.

How does a pulse oximeter work?

The pulse oximeter is a small electronic device that is typically clipped onto a fingertip or other body part.

The device emits light that has the ability to penetrate several layers of the finger, including the nail, skin, tissue, and blood.

It’s a sneaky sensor, that emits light, measuring the rays that dodge tissue and blood on the flip side of your finger.

The device shows the numerical value of oxygen saturation within your blood.


The Advantages and Drawbacks of a Pulse Oximeter

Pulse oximetry provides benefits compared to conventional ways of measuring oxygen levels in the blood. Traditional methods for analysing blood samples involve drawing arterial blood which can be painful and take at least 15 minutes. Pulse oximetry, on the other hand, is non-invasive and provides quick results. Additionally, pulse oximeters have the ability to provide ongoing monitoring of an individual’s blood oxygen levels for extended periods of time.

Studies have shown that pulse oximetry may be less accurate when compared to arterial blood gas testing.

Direct blood tests offer more comprehensive information on additional blood gases, such as carbon dioxide, when compared to pulse oximetry.

In what situations is it appropriate to use pulse oximeters?

Pulse oximeters are commonly utilised in various health care environments. During routine physical examinations, they are commonly used to rapidly evaluate a person’s overall health in general practice. Pulse oximeters are commonly used to measure blood oxygen saturation, which is now considered a vital sign along with temperature, blood pressure, pulse, and respiration rate to evaluate a person’s health status.

Pulse oximetry is a commonly utilised method for monitoring patients with heart and lung ailments, particularly those at risk for decreased blood oxygen levels.

This method also has broader applications in general medical practice.

In clinical settings, these are commonly utilised in the following scenarios:

  • To observe and assess patients prior to, during, and following surgical procedures, including while under anaesthesia.
  • To observe individuals taking specific medicines that could potentially decrease breathing and pulmonary performance.
  • To monitor lung function of individuals with respiratory, cardiovascular, neurological or lymphatic conditions that can lead to decreased blood oxygen level.
  • To evaluate individuals who have sleep disorders.

Patients with pre-existing respiratory conditions often use pulse oximeters at home to monitor their blood oxygen saturation levels under medical supervision.

What do particular pulse oximeter measurement outputs mean?

The resting oxygen saturation level for a healthy individual typically ranges from 95% to 100%.

At elevated altitudes, oxygen saturation levels may experience a minor decrease. If an individual’s oxygen saturation readings fall below 92%, seek medical attention.

Medical professionals advise seeking urgent medical attention if blood oxygen saturation levels fall to 88% or below.

Individuals with complex lung disorders may have oxygen saturation levels below the normal range during rest. This must be discussed with medical professionals to understand the appropriate levels based on specific medical indications.


What is the level of accuracy of pulse oximeter readings?

The typical accuracy range of pulse oximeters when measuring blood oxygen saturation levels is 2% to 4%, meaning that the reading can deviate by the same percentage from the actual oxygen level in arterial blood.

Various factors may affect the performance or precision of a pulse oximeter.

The use of nail polish and artificial nails, as well as certain dyes used in medical procedures and diagnostic tests, can interfere with the accuracy of light transmission in devices that emit red and infrared light. In addition, excessive motion can result in inaccurate readings.

Several factors, such as skin temperature and thickness, can influence the precision of pulse oximeters. Additionally, smoking tobacco may affect the accuracy of the device. Research indicates that pulse oximetry may be less effective for individuals with darker skins tones, potentially leading them to be undiagnosed with significantly low blood oxygen levels more frequently than those who have a lighter skin pigmentation.

Heart Sure Bluetooth Pulse Oximeter

Measuring oxygen saturation levels in the blood is crucial for detecting potential medical emergencies. The Heart Sure Bluetooth Pulse Oximeter provides quick and accurate readings of both your oxygen saturation and pulse rate.

The Heart Sure Bluetooth Pulse Oximeter* is the number 1 Pulse Oximeter brand in Australian pharmacy^ and measures Oxygen Saturation (SpO2) and Pulse Rate through the index finger, providing a convenient and speedy process. By using Bluetooth connectivity and the Jumper Health App, you can record and graph your oxygen saturation measurements for future analysis, and show the results to your health professional. This device is portable and useful for measuring pre/post-exercise and pre/post-operative conditions.

The advanced algorithm is capable of reducing motion interference and enhancing the precision of low perfusion measurements. The Perfusion index (PI) measures the pulse strength at the sensor site of the SpO2 device on your finger. A low PI indicates a weaker pulse. The Perfusion Index measures pulse strength, starting at 0.2% for a weak pulse and increasing for stronger pulses.

 Why not try one today! 

*Always read the label and follow the directions for use. Consult your health professional to evaluate the readings.

^IQVIA, National Australian Pharmacy Sell-Out Sales, Oximeters MAT March 2023.


1. Pulse Oximetry > Fact Sheets > Yale Medicine

2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4654337/



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