Microcirculation alterations in severe COVID-19 pneumonia

Purpose: To assess the presence of sublingual microcirculatory and skin perfusion alterations in COVID-19 pneumonia. Materials and methods: This is a preliminary report of a prospective observational study performed in four teaching intensive care units. We studied 27 mechanically ventilated patients with acute respiratory distress syndrome secondary to COVID-19. Sublingual microcirculation was assessed by hand-held videomicroscopy. A software-assisted analysis of videos was performed. We also measured capillary refill time. Results: Patients were hemodynamically stable with normal lactate (1.8 [1.6-2.5] mmol/L) and high D-dimer (1.30 [0.58-2.93] mu g/mL). Capillary refill time was prolonged (3.5 [3.0-5.0] s). Compared to previously reported normal values, total and perfused vascular density (21.9 +/- 3.9 and 21.0 +/- 3.5 mm/mm(2)) and heterogeneity flow index (0.91 +/- 0.24) were high; and the proportion of perfused vessels (0.96 +/- 0.03), microvascular flow index (2.79 +/- 0.10), and red blood cell velocity (1124 +/- 161 mu m/s) were reduced. The proportion of perfused vessels was inversely correlated with total vascular density (Pearson r = -0.41, P = 0.03). Conclusions: COVID-19 patients showed an altered tissue perfusion. Sublingual microcirculation was characterized by decreases in the proportion of perfused vessel and flow velocity along with high vascular densities. This last finding might be related to enhanced angiogenesis or hypoxia-induced capillary recruitment. (C) 2020 Published by Elsevier Inc.

Automated summary

This study evaluated the sublingual microcirculation of 27 mechanically ventilated patients with COVID-19 pneumonia and found altered tissue perfusion, characterized by high vascular densities and decreased proportion of perfused vessels. These findings suggest that COVID-19 may lead to microcirculatory abnormalities, potentially related to enhanced angiogenesis or hypoxia-induced capillary recruitment.