The microcirculatory response in critically ill COVID-19 patients is dependent on the severity of disease

Abstract The objective of this study was to investigate the relation between sublingual microcirculatory parameters and the severity of the disease in critically ill coronavirus disease 2019 (COVID-19) patients in the initial period of Intensive Care Unit (ICU) admission in a phase of the COVID-19 pandemic where patients were being treated with anti-inflammatory medication. In total, 35 critically ill COVID-19 patients were included. Twenty-one severely ill COVID-19 patients with a Sequential Organ Failure Assessment (SOFA) score below or equal to 7 were compared to 14 more severely ill COVID-19 patients with a SOFA score exceeding 7. Microcirculatory measurements were performed during the initial day of ICU admission. An increase in diffusive capacity of the microcirculation (total vessel density, functional capillary density, capillary hematocrit) and an increased perfusion of the tissues by red blood cells was found in the more severe critically il patients (SOFA 7–9) compared to the less severe critically ill COVID-19 patients. This study further shows that this adaptive response of the microcirculation is maintained despite the administration of anti-inflammatory medication.