Covid Crisis: Why having a pulse oximeter at home is more important than ever

As the number of novel coronavirus (Covid-19) cases rise across the globe, most of us have started keeping a better check on our health, while also tracking any symptoms which might develop. While it might be easier to assess common Covid-19 symptoms like a sore throat or a fever, it is not very easy to track other symptoms like blood oxygen level.

One of the most common and arguably ignored symptoms of this new disease is a falling blood oxygen level in patients. Blood oxygen level in simple terms is the amount of oxygen red blood cells (RBCs) carry.

A normal blood oxygen level ensures that your body functions effectively. However, any dip in blood oxygen levels can interfere with the functions of the brain and the heart. It leads to a condition called hypoxia. Covid-19 causes a condition called ‘Covid pneumonia’, wherein the air sacs of your lungs get filled with fluid which in turn might lead to respiratory failure.

Doctors are recommending people to keep tabs on the blood oxygen levels. While there are lab tests that can determine if your blood is low on oxygen, you can also check it on your own by using a small portable device called the pulse oximeter.

The use of pulse oximetry can be traced back to 1970s when the technology was first discovered by Japanese scientists. A pulse oximeter is an electronic machine which helps in measuring one’s heart rate and the oxygen saturation level, which is the percentage of oxygen being carried by RBCs. It helps in assessing how effectively oxygen is being distributed across the body by RBCs. Once it is attached to the tip of your finger, it transmits two wavelengths to measure the pulse rate and oxygen.

Though these devices can be used both on your hands and toes, a finger clip pulse oximeter can be attached only to your fingertips. Once you fit the device on your finger, give it 10-15 seconds for the oximeter’s red light to pass through the fingers and the pulse waveform is back to its normal rhythm. 

Any reading below 95 Sp02 is low and requires immediate medical assistance. As your blood oxygen levels dip, you might experience low blood pressure and breathlessness. The SPo2 level shows the percentage of blood saturation. The readings of a pulse oximeter have a 2% window for error. In other words, the reading of the device can be 2% higher or lower than the actual blood saturation level of your body.

Monitoring one’s blood oxygen level becomes even more important if you are in home quarantine. Many a time, patients might not experience any physical symptoms like shortness of breath and rapid heartbeat but their blood oxygen may still drop below the normal level. This condition is called ‘silent or happy hypoxia’ and can is difficult to trace, except with a pulse oximeter or regular tests. 

Apart from pulse oximeters, smartwatches featuring real-time oxygen monitors are also helpful in gauging blood oxygen levels. There are several brands that have launched smartwatches to track blood oxygen on the go. However, doctors have warned users against relying blindly on such fitness trackers as they are not medically approved and do not always present the correct picture.

Medical experts have maintained that no clinical studies have been conducted to review how effectively smartwatches can track health indicators like blood oxygen level and heart rate. Many manufacturers of such smartwatches have stated that such products cannot replace a medical professional or a medical device and they cannot be used to diagnose or treat a disease. Users can interpret the data generated by these devices only for their personal reference.

There are several apps available for different operating systems through which you can measure your blood oxygen level. Doctors say that they do recommend users to use apps and fitness trackers to screen any potential Covid-19 symptoms early and can even be helpful for asymptomatic patients. However, they are not recommended for serious patients or those with co-morbidities like hypertension, cardiac problems, and diabetes as these devices are not always reliable.

Doctors have also claimed that most smartphones do not have the required technology which enables an app to measure blood oxygen percentage. According to medical experts, a pulse oximeter uses infrared and red wavelengths to measure the blood oxygen level. Also, the device uses a small chip. An app will be able to give you an accurate reading only if these chips are present in your phone.

You can visit a chemist or pharmacy to get a pulse oximeter, while one can also buy the device online. The starting price for one of these devices is as low as Rs 500 and it can go up to Rs 3,000. If you still are going out for work or a personal reason despite the restrictions, it is advisable that you track your blood oxygen level with a pulse oximeter regularly.