key: cord-323631-r31sfq90 authors: Edul, Vanina Siham Kanoore; Eguillor, Juan Francisco Caminos; Ferrara, Gonzalo; Estenssoro, Elisa; Siles, Daniel Shiovan Páez; Cesio, Cristián Emanuel; Dubin, Arnaldo title: Microcirculation alterations in severe COVID-19 pneumonia date: 2020-10-17 journal: J Crit Care DOI: 10.1016/j.jcrc.2020.10.002 sha: doc_id: 323631 cord_uid: r31sfq90 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] μg/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 μm/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. Microvascular thrombosis has recently been diagnosed in patients with COVID-19, and it has been proposed to mediate the pathogenesis of organ injury in this disease [1] . While widespread pulmonary microvascular thrombosis was demonstrated [2] , reports about the compromise of extrapulmonary microvessels are inconsistent. Some anatomopathological reports found extrapulmonary microvascular thrombosis, but others failed to show such alterations [3, 4] . Recently, sublingual microcirculatory abnormalities were shown in 12 patients with COVID-19 pneumonia [5] . Since microvascular densities were inversely correlated with D-dimer levels, these abnormalities might have resulted from microthrombosis. A growing body of evidence suggests that the microvascular disorder plays a role in the pathogenesis of septic shock and is related to outcome [6] . Thus, our goal was to assess the characteristics of sublingual microcirculation and skin perfusion in patients with acute respiratory distress syndrome (ARDS) secondary to COVID-19. In this report, we show the preliminary results of a prospective multicenter study. We 3-h before the measurements. Sublingual microcirculation was assessed by means of handheld videomicroscopy, within the first 3 days of ICU admission. Relevant aspects of video acquisition and software-assisted analysis are described elsewhere [6] . Several videos were taken in each patient. Based on the total microcirculation image quality score, the best three videos were selected for analysis [7] . Analysis was focused on small microvessels (diameter <20 µm) whereas large microvessels were only considered for ruling out compression artifacts. For the calculation of proportion of perfused vessels and perfused vascular density, we took into account microvessels with continuous and sluggish flow. Capillary refill time was measured by applying firm pressure to the ventral surface of the right index finger distal phalanx with a glass microscope slide. The pressure was increased until the skin was blank and maintained for 10 seconds. The time for return of the normal skin color was registered with a chronometer, and a refill time greater than 3 seconds was defined as abnormal. The respective institutional review boards approved this study and waived patient informed consent. We present continuous variables as median (interquartile range [IQR]) or mean ± SD, and categorical variables as numbers and percentages. Values of COVID-19 patients were Microvascular thrombosis: experimental and clinical implications Pulmonary Vascular Endothelialitis, Thrombosis, and Angiogenesis in Covid-19 Pulmonary and systemic involvement of COVID-19 assessed by ultrasound-guided minimally invasive autopsy Postmortem Examination of Patients With COVID-19 Microvascular alterations in patients with SARS-COV-2 severe pneumonia Quantitative assessment of the microcirculation in healthy volunteers and in patients with septic shock The microcirculation image quality score: development and preliminary evaluation of a proposed approach to grading quality of image acquisition for bedside videomicroscopy Effect of a Resuscitation Strategy Targeting Peripheral Perfusion Status vs Serum Capillary Recruitment in Response to Tissue Hypoxia and Its Dependence on Red Blood Cell Deformability Angiopoietin-2 as a marker of endothelial activation is a good predictor factor for intensive care unit admission of COVID-19 patients Pulmonary post-mortem findings in a series of COVID-19 cases from northern Italy: a two-centre descriptive study The respective institutional review boards approved this study and waived patient informed consent. Not applicable. The authors declare that they have no competing interests.