How severe COVID-19 disrupts tissue microcirculation

Although COVID-19 is primarily a respiratory syndrome, it has also been observed and detected in other organs.

Several studies have shown that COVID-19 causes diseases in the circulatory system, where the virus damages the endothelium, the membrane that lines the inside of the heart and blood vessels.

The correct circulation of blood in the smallest vessels of our body is of crucial importance, since the branching of these microvessels is the end point of the circulatory system, where the transfer of oxygen and the transport and exchange of heat, nutrients take place. or waste products.

To further investigate the extent to which this disease affects the microcirculation, an international team of researchers carried out a clinical study to monitor endothelium of critical COVID-19 patients, admitted to different intensive care units (ICU) around the world.

Monitoring of a patient in the Intensive Care Unit of the Hospital Parc Taulí. Photo: ICFO

After months of data collection, the researchers have published their preliminary results in the journal Critical Care, carried out in six different hospitals in Spain, Mexico and Brazil, where they provide data on patients with acute respiratory distress syndrome caused by COVID-19, and on healthy adults,

NIRS technology to monitor microcirculation

The researchers used near-infrared spectroscopy (with a non-invasive, portable, and wireless device) to study localized oxygen saturation in tissues and hemoglobin concentration in blood. They also made an assessment of the degree of severity of the disease. They measured oxygen saturation, tissue metabolic rate, and microvascular reactivity, which is how the tissue responds to occlusion.

After collecting data from more than 100 people, the team found that in patients with severe COVID-19 there were alterations in the circulation process within the tissue microvessels. They observed that, in terms of respiratory involvement, the level of these alterations was directly associated with the severity of the disease. The results emphasize the role of endothelial function and highlight the relationship between its dysfunction and the severity of COVID-19. With these observations, the researchers suggest that monitoring endothelial function could be helpful in predicting the course of COVID-19 and other medical conditions.

“These preliminary results are very relevant in several aspects”, comments Dr. Jaume Mesquida, doctor at the Parc Taulí Hospital. “First, we have reinforced the idea that lhe severe forms of COVID-19 are a systemic disease that affects the body’s microvessels. Second, we have established that the severity of the disease, determined mainly by pulmonary involvement, correlates with the deterioration of the microvascular response in the peripheral skeletal muscle. And finally, we have been able to non-invasively monitor this microvascular deterioration. A non-invasive tool could be useful in the early detection of potentially critical patients. In addition, it will help us select and monitor the response to new therapies targeting microvessels in the course of COVID-19. “

The team brings together researchers and physicians from institutions in four countries. Researchers from ICFO (Institute of Photonic Sciences), project coordinator, the Physics Institute of the University of Campinas in Brazil and the University of Southwest Texas joined forces with doctors from the Parc Taulí University Hospital, the Parc Salut Mar Hospital, the General Hospital of Mexico, the Hospital Clinic of Barcelona and the Vall d’Hebron University Hospital. (I)

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