Silent hypoxemia recognized as a symptom of coronavirus COVID-19

Spanish researchers have hypothesized what is the reason for the decrease in blood oxygen levels in those infected with the coronavirus infection COVID-19. The results of the scientific work of experts were published in the journal Function.

Silent hypoxemia recognized as a symptom of coronavirus COVID-19

According to the information and news portal KURSK.COM, experts suggested that infection with coronavirus of carotid bodies - chemoreceptors, which are responsible for assessing the partial pressure of oxygen in the blood, leads to a decrease in its level.

Over the past year, during which the COVID-19 coronavirus infection pandemic is raging in the world, it became clear that the majority of COVID-carriers, whose course of the disease is accompanied by severe pneumonia caused by the coronavirus, also has hypoxemia - a significant decrease in the level of oxygen in arterial blood.

However, at the same time, patients do not have shortness of breath or rapid breathing, characteristic of hypoxemia, the cause of which is pneumonia.

Citizens with ordinary hypoxemia, as a rule, have a feeling of shortness of breath and rapid breathing, which leads to an increase in oxygen consumption by the body. The same reflex mechanism is triggered by the carotid bodies - small organs located on either side of the neck next to the carotid artery. By fixing the drop in oxygen in the blood, the bodies send signals to the brain to stimulate the respiratory center.

In patients with "silent hypoxemia", which is typical for coronavirus, this defense mechanism does not work. As a result, a person develops a sudden oxygen imbalance and death occurs when a critical level is reached.

According to researchers from the Institute of Biomedicine of Seville, the Virgen del Rocío y Macarena University Hospitals in Seville, the Universidad de Sevilla, the Biomedical Research Networking Center on Neurodegenerative Diseases in Madrid and National Center for Biotechnology (Centro Nacional de Biotecnología) of Spain, "silent hypoxemia" in COVID-carriers may be the result of infection with the SARS-CoV-2 virus of carotid bodies that cease to function normally.

“Many patients with coronavirus infection COVID-19 have an atypical and perplexing clinical manifestation - severe hypoxemia with blood pressure oxygen levels even below 50 millimeters of mercury and no shortness of breath or rapid breathing. This can lead to decompensation and, as a consequence, a rapid deterioration in the clinical state of the virus carrier, ”experts say.

Scientists have carried out a series of experiments that showed a high presence of the ACE2 enzyme in carotid bodies. It is this protein that the SARS-CoV-2 virus uses in order to penetrate and infect the cells of the human body. According to the authors of the study, infection of human carotid bodies in the early stages of the disease affects their function of determining the level of oxygen in the blood, the bodies that are not able to function normally “do not notice” the critical drop in oxygen in the arteries.

Experts are now testing their hypothesis using experimental models. If the concerns are confirmed, efforts will need to be focused on the development of new therapeutic methods that will use carotid body activators not associated with the oxygen sensitivity mechanism as respiratory stimulants in COVID patients.