Pulse Oximetry: Uses, Mechanism, and Role Against COVID-19

What is Pulse Oximetry?

Pulse oximetry is a test used to measure the oxygen saturation levels in the blood. It detects the slightest changes in blood oxygen levels and determines the efficiency of the oxygen-carrying capacity of blood to the extremities. 

A pulse oximeter is a small device that uses a clip-like sensor mostly attached to the finger.

Uses of Pulse Oximetry:

Pulse oximetry comes in handy to monitor the diseases that affect blood oxygen saturation levels. These diseases include:

• COPD
• Asthma
• Pneumonia
• Lung cancer
• Anemia
• CHD
• Myocardial infarction

Other than disease conditions, pulse oximetry can also be used for various other reasons;

• To access the function of lung medication
• To evaluate if breathing support is required
• To access the functioning of the ventilator 
• To monitor oxygen level post-surgery
• To access the need for oxygen therapy
• To determine how well oxygen therapy is responding.
• To access sleeping disorders

Types of Pulse Oximeters?

Broadly, pulse oximeters can be divided into 3 types:

1. Fingertip Pulse Oximeter: They are small and noninvasive oximeters convenient to be used at home. The oximeter is attached to the fingertip, and the reading is shown on the device’s screen within seconds. The device works by shining a cold light through the fingertip. 
2. Handheld Pulse Oximeters: They are also known as “SAT monitors.” It is mainly used in hospitals by experts. It contains a reusable or disposable sensor at one end of a lengthy cable called “pulse ox.” For a reusable sensor, click here. The other end is plugged into a handheld oxygen saturation monitor. 
3. Fetal Pulse Oximeter: The sensor has a fulcrum tip that is used to assess the oxygen saturation of the fetus directly. The sensor gets passed through the cervix and rests upon the baby’s face where membranes are ruptured. It’s also connected to a monitor which continuously reads fetus’s oxygen levels. 

How to Take Reading?

The following steps should be strictly followed in order to take an accurate reading through a pulse oximeter:

• First, remove any nail polish, jewelry, or false nail from the fingertip.
• Make sure that your hand is warm and relaxed.
• Take the rest five minutes before taking the reading to keep your heart rate steady.
• Rest your hand on your chest at the level of your heart and keep it still.
• Switch on the pulse oximeter. Place the sensor on your fingertip. The Middle and index fingers are the best choices for attaching the pulse oximeter. Avoid attaching the device to the earlobe.
• It might take some time to get a steady reading. So, keep the device on the fingertip for about a minute or more if necessary. 
• Once the reading becomes steady for 5 seconds, record the highest figure.
• Be careful and avoid mixing the reading of heart rate and oxygen level.

Optimum Readings:

According to the American Thoracic Society, more than 89 percent of the blood should be saturated with oxygen to keep the cells healthy and meet their requirements. Oxygen saturation below this level temporarily may not cause damage. But consistent low oxygen levels in the body should be taken seriously and requires immediate medical attention.

Role of Pulse Oximetry Against COVID-19:

Pulse oximetry helps keep watch over the individual’s health, and it is an excellent source to evaluate when medical care is needed. For example, during the pandemic, covid positive patients were recommended to have a fingertip pulse oximeter at home to monitor their oxygen levels and assess the need for medical help in case of deteriorating health.