Microcirculatory, Endothelial, and Inflammatory Responses in Critically Ill Patients With COVID-19 Are Distinct From Those Seen in Septic Shock: A Case Control Study

Critically ill patients with COVID-19 infection frequently exhibit a hyperinflammatory response and develop organ failures; however, the underlying mechanisms are unclear. We investigated the microcirculatory, endothelial, and inflammatory responses in critically ill COVID-19 patients and compared them to a group of patients with septic shock in a prospective observational case control study. Thirty critically ill patients with COVID-19 were compared to 33 patients with septic shock. Measurements of sublingual microcirculatory flow using Incident Dark Field video-microscopy and serial measurements of IL-6 and Syndecan-1 levels were performed. COVID-19 patients had significantly less vasoactive drug requirement and lower plasma lactate than those with septic shock. Microcirculatory flow was significantly worse in septic patients than those with COVID-19 (MFI 2.6 vs 2.9 p 0.02, PPV 88 vs 97% P < 0.001). IL-6 was higher in patients with septic shock than COVID-19 (1653 vs 253 pg/mL, P 0.03). IL-6 levels in COVID 19 patients were not elevated compared to healthy controls except on the day of ICU admission. Syndecan-1 levels were not different between the two pathological groups. Compared to patients with undifferentiated septic shock an overt shock state with tissue hypoperfusion does not appear typical of COVID-19 infection. There was no evidence of significant sublingual microcirculatory impairment, widespread endothelial injury or marked inflammatory cytokine release in this group of critically ill COVID-19 patients.

Automated summary

In critically ill COVID-19 patients, there is less vasoactive drug requirement, lower plasma lactate levels, and no evidence of significant sublingual microcirculatory impairment, widespread endothelial injury, or marked inflammatory cytokine release compared to patients with septic shock. The hyperinflammatory response and organ failures seen in septic shock do not appear typical of COVID-19 infection.