COVID-19 : Do you have a pulse oximeter? This is how you should use it, according to the FDA

Watch the attack of the covid-19 to the lungs in 3D 1:16

(CNN Spanish) – The pulse oximeter has become one of the tools to monitor the progression of symptomatic coronavirus. The device allows to measure the oxygen saturation in the blood.

Recently, the US Food and Drug Administration (FDA) issued recommendations on its use. In this episode, Dr. Elmer Huerta reviews the new suggestions.

You can listen to this episode on Spotify or your favorite podcast platform or read the transcript below.

Hello, I am Dr. Elmer Huerta and this is your daily dose of information on the new coronavirus. Information that we hope will be useful to take care of your health and that of your family.

Today we will see the latest recommendations from the United States Food and Drug Administration (FDA) on the proper use of the pulse oximeter.

Treatment of covid-19 at home

In this pandemic year, we have learned a lot about the covid-19 disease and its complications.

In the first place, and almost since the first study in China of more than 72,000 patients with covid-19, the proportion of severity of the disease maintains a ratio of 81% of mild or asymptomatic cases, 14% of severe cases and 5% of severe or critical cases.

This knowledge is important because it indicates that 95% of covid-19 cases can be treated at home, and that only around 5% of patients may need hospitalization for some complication.

In that sense, the complication that leads to hospitalization is respiratory failure due to pneumonia caused by covid-19.

That is why people with covid-19 should be at all times alert to the development of pulmonary complications caused by the infection, and in that sense, the use of a pulse oximeter is essential to realize if the disease is developing. complicating.

What is a pulse oximeter?

The pulse oximeter is a device that reads the oxygen saturation on the tip of one of the fingers of the hand, and it can be prescribed by a doctor, or it can be freely purchased on the Internet or in stores and pharmacies.

Pulse oximeters work by transmitting a combination of red light and infrared light, both of which are capable of detecting the amount of oxygen carried by red blood cells. This amount of blood in the blood cell is called oxygen saturation, and at sea level it must always be between 95% and 100%.

The idea is then, that by frequently measuring the oxygen saturation in the person with covid-19 at home, we can find out if the oxygen saturation decreases to less than 95% and we seek early help to avoid arriving too late to the hospital.

A recent Peruvian study, for example, showed that patients who presented to the hospital with less than 90% saturation had a higher risk of dying.

To be more precise, those who arrived with an oxygen saturation of between 85 and 89% had a risk of dying almost twice as high as those who arrived with a saturation of 90% or more. Similarly, those patients with saturation between 80 and 84% had a 4 times greater risk, and those with less than 80% saturation had an almost 8 times greater risk of dying.

Why should I have a pulse oximeter at home?

Having a pulse oximeter at home is therefore very important, but according to the FDA, there are some basic rules that must be followed for its use.

For example, the FDA says in its statement, there are several factors that can affect the accuracy of the oximeter reading, such as poor circulation, dark pigmentation, skin thickness and temperature, cigarette smoking, and use of nail polish.

Regarding skin color, says the FDA, there are studies that show differences in the reading accuracy of pulse oximeters, according to the pigmentation of dark or light skin.

In general, says the FDA, these differences are usually smaller when saturations are greater than 80% and greater when saturations are less than 80%.

In this regard, one study reported that black patients had almost three times the frequency of low blood oxygen levels not detected by pulse oximetry compared to white patients.

Recommendations for the proper use of the pulse oximeter:

To get the best reading from a pulse oximeter, the FDA recommends that when placing the oximeter on your finger:

Make sure the nail is free of enamel Hand is warm, relaxed and held below heart level You should also sit still and do not move the part of the body where the pulse oximeter is located Wait a few seconds for the reading to stop change and display a fixed number.

It is very important to write down your oxygen levels in a notebook, with the date and time of the reading, so that you can monitor your saturation and inform your doctor.

On the other hand, it is very important that you pay attention to the trend of the readings. This means that if you start with a normal saturation of 97 for example and, in the following days, you notice that it is gradually decreasing, you should immediately notify your doctor, regardless of the presence of symptoms.

This is because there are cases in which oxygen saturation falls, indicating lung damage, but which, however, do not present symptoms.

Finally, do not rely solely on a pulse oximeter to assess your health or oxygen level, you should be aware of symptoms of respiratory failure, such as bluish discoloration of the face, lips or nails, shortness of breath, difficulty breathing or worsening cough, restlessness and discomfort, chest pain or tightness, and a fast or racing pulse.

Do you have questions about the coronavirus?

Send me your questions on Twitter, we will try to answer them in our next episodes. You can find me at @DrHuerta.

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If you have any questions you can send them to Dr. Elmer Huerta via Twitter. You can also head over to for all episodes of our “Coronavirus: Reality vs. Reality” podcast. fiction”.