Pulse Oximeter – Purpose, Uses and How Does it Work?

April 19, 2024

What is an Oximeter?

It took us a pandemic to get familiar with this medical equipment. Earlier only a bunch of people knew what an oximeter was but as our life took a drastic change when we were hit by the pandemic, we came across certain medical terms and gadgets that helped us in those rough patches of Covid 19. Every home has at least one pulse oximeter with them and now they are aware of its usage. However, some are still unaware of it and how to use it. Let us understand first, what is an oximeter? Pulse oximetry is a non-invasive and painless test that measures our oxygen saturation level or the oxygen levels in our blood. It is capable of rapidly detecting even the slightest changes in how efficiently oxygen is being carried to the extremities furthest from the heart, including the legs and the arms.

The pulse oximeter is a petite, clip-like device that works by attaching to a body part, such as toes or an earlobe. The most common place it has is on your finger, used in a critical care setting like emergency rooms or hospitals. Doctors, like pulmonologists, may prefer using it in the office.

Purpose and Uses

The pulse oximeter’s main function is to ensure how well our heart is pumping oxygen through our body.

Patient with a critical condition that affects their oxygen levels uses it to monitor their oxygen supply. A patient who is affected with conditions are:

chronic obstructive pulmonary disease (COPD)
asthma
pneumonia
lung cancer
anemia
heart attack or heart failure
congenital heart defects

There are several different common use cases for pulse oximetry, including:

To review the effectiveness of lung medication.
To assess the requirement of breathing.
To calculate how helpful a ventilator is
To observe oxygen levels that require sedation during or after surgical
To decide the effectiveness of supplemental oxygen therapy
To review the tolerance level of an individual’s physical activity
To assess momentarily stop breathing while sleeping, like in case of sleep apnea or sleep study.

How does it work?

An oximeter is unique in its way and how it works is quite interesting. While taking a pulse oximeter reading, place a small clamp-like device on your finger, earlobe, or toe. You will see small beams of light pass through the blood in the finger, measuring the amount of oxygen. This function is by measuring changes of light absorption in oxygenated or deoxygenated blood. It is a smooth and painless procedure.

Soon you will get to know your oxygen saturation levels along with your heart rate with the help of a pulse oximeter.

Procedure STEPS

The pulse oximeter can be used at the hospital or just by sitting at your home. Some patients are advised by doctors to assess a regular record of their saturation level at their home as well.

The procedure to use a pulse oximeter is quite convenient and easy. You just need to follow these steps:

To take a reading of your oxygen saturation level, a clip-like device is placed on your fingers, earlobe, or toe. There might be a slight pressure on the finger, but it will be a painless process. In some cases, a small probe may be placed on your finger or forehead with a sticky adhesive. Rings, any kind of accessories, or nail polish should be avoided.
The probe should be kept intact as long as required to monitor your pulse and oxygen saturation. If you wish to monitor your physical capacity, then it should be practiced during the extent of the exercise and the recovery period. However, during surgery, the oximeter will be placed before the surgery and will only be removed once the surgery is over, and you are awakened and no longer under supervision.
After taking the reading, the probe will be removed.

Pulse oximeter readings

The device is effective and has considerate accurate test results. Pulse oximeter results are reliable, especially when using high-quality equipment found in most medical offices or hospital settings. It consistently gives results with a mere 2% difference from the actual results. Suppose upon taking the test, your reading comes 82%, then the chance of accuracy relies on between 80%-84%. The quality and evaluation of an individual’s matters, such as movement while taking the reading, nail polish, temperature, the accessory may affect the results.

In medical terms, generally, 89% of blood should be carrying oxygen. This oxygen saturation is required to maintain your cells and body healthy. A temporarily low saturation level than this might not be injurious, however, constant instances of low saturation levels may have a hazardous effect

A healthy individual has a balanced 95% oxygen saturation level. A level of 92 percent indicates potential hypoxemia or insufficiency in oxygen reaching tissues in the body.

What’s next?

An oxygen saturation level test is necessary for any treatment or surgery as it helps to indicate the requirement of oxygen if your oxygen saturation is low. It helps in evaluating what tests and treatments are needed. If your oxygen saturation is low, then you may require a steady supply of oxygen for any further treatment.

If you have any doubts then talk with your doctor, they can lead you with the usage and dos and don’ts of the equipment.

The pulse oximeter is a rapid, noninvasive, and entirely painless test. There are no potential risks attached aside from skin irritation from the adhesive used in some types of probes.

What happens if your oxygen level is too low?

When your blood oxygen level reaches below the typical range, some symptoms can occur:

shortness of breath
chest pain
confusion
headache
rapid heartbeat

Symptoms of cyanosis may occur if the low blood oxygen level does not reach its normal range. You may see a blue discoloration of the nail beds, skin, and mucus membranes which is a general hallmark sign of this condition.

With the occurrence of cyanosis, one should never neglect such symptoms and seek immediate medical attention. Cyanosis is considered an emergency. Negligence of symptoms can lead to respiratory failure, which can be life-threatening.

How to adjust your blood oxygen level

Home supplemental oxygen is considered as medication and used when your blood oxygen level is extremely low. To boost your oxygen level, supplement oxygen is the best option. Taking the supplement should be under the guidance of your doctor. Follow the instructions thoroughly to avoid any complications.

What causes blood oxygen levels to below?

Conditions that can negatively affect your blood oxygen level include:

COPD, including chronic bronchitis and emphysema
acute respiratory distress syndrome
asthma
collapsed lung
anemia
congenital heart defects
heart disease
pulmonary embolism

Inhaling oxygen-containing air and exhaling carbon dioxide can be prevented by your lungs due to such conditions. Similarly, there are chances of blood disorders and problems with your circulatory system that may prevent your blood from picking up oxygen and transporting it throughout your body.

Smoking gives an inaccurately high pulse oximeter reading due to carbon dioxide build-up in your blood. People who smoke should take their reading with an ABG only for an accurate reading.

What affects pulse oximeter readings?

Nail polish color and decals can affect readings, like acrylic or gel nails. If you have nail polish on the pulse oximeter will absorb 660 nm [nanometers] or 940 nm of light,” which will affect your reading. This is specifically seen in black, green, and blue nail polish. Also, keep in mind that artificial acrylic nails may also affect the accuracy of pulse oximeter readings.

Furthermore, the following can affect the accuracy of readings:

anemia
low blood pressure
skin with more pigment
low body temperature
intravascular dyes, which are used at a hospital for certain tests

“Dark skin and intravascular dyes in the blood also lead to obscurity in reading oxygen saturation level because the colors make the pulse oximeter too hard to take the readings.”

“Low blood pressure implies blood volume, and anemia means fewer blood cells, which results in the sensor complexity evaluating the data. In the same manner, low body temperature also makes blood vessels compress, making it hard to read as well.”

What types of pulse oximeters are available?

A pulse oximeter probe or sensors can be attached to the finger, nose, ear, toes, and forehead areas.

To ensure the most accurate rate of reading one must ensure clamping the oximeter to the finger, specifically the middle finger in contrast to other parts of the body. A brisk 5 mins walk before taking the readings has proven to be more effective. However, in hospitals oximeters which are different than the ones we use at home are linked to machines that measure blood pressure and temperature and can be linked to simultaneous measurement of a patient’s heart rhythm.

While home-based pulse oximeters have only the capacity to measure the pulse oxygenation and the heart rate, hospital systems can provide a printout of readings. With new advanced technology, oximeters can now be linked with your Smartphone, making your life easier and can keep the record for future references.

How to choose?

When shopping for at-home pulse oximeters. There are different brands available on the market.

While purchasing an oximeter keep in mind to get your hands on the ones which are labeled ‘for medical use’ and ‘FDA (Food and Drug Administration) approved. As there are many fraud brands and sellers. The most oximeter can also measure your heart rate.