Hemodynamic Characteristics of Mechanically Ventilated COVID-19 Patients: A Cohort Analysis

Abstract

Background. Solid data on cardiovascular derangements in critically ill COVID-19 patients remain scarce. The aim of this study is to describe hemodynamic characteristics in a cohort of COVID-19-related critically ill patients. Methods. A retrospective observational cohort study in twenty-eight consecutive mechanically ventilated COVID-19 patients. Pulse contour analysis-derived data were obtained from all patients, using the PiCCO® system. Results. The mean arterial pressure increased from 77 ± 10 mmHg on day 1 to 84 ± 9 mmHg on day 21 ( $p=0.04$ ), in combination with the rapid tapering and cessation of norepinephrine and the gradual use of antihypertensive drugs in the vast majority of patients. The cardiac index increased significantly from 2.8 ± 0.7 L/min/m2 on day 1 to 4.0 ± 0.8 L/min/m2 on day 21 ( $p<0.001$ ). Dobutamine was administered in only two patients. Mean markers of left ventricular contractility and peripheral perfusion, as well as lactate levels, remained within the normal range. Despite a constant fluid balance, extravascular lung water index decreased significantly from 17 ± 7 mL/kg on day 1 to 11 ± 4 mL/kg on day 21 ( $p<0.001$ ). Simultaneously, intrapulmonary right-to-left shunt fraction (Qs/Qt) decreased significantly from 27 ± 10% in week 1 to 15 ± 9% in week 3 ( $p=0.007$ ). PaO2/FiO2 ratio improved from 159 ± 53 mmHg to 319 ± 53 mmHg ( $p<0.001$ ), but static lung compliance remained unchanged. Conclusions. In general, this cohort of patients with COVID-19 respiratory failure showed a marked rise in blood pressure over time, not accompanied by distinctive markers of circulatory failure. Characteristically, increased extravascular lung water, vascular permeability, and intrapulmonary shunt diminished over time, concomitant with an improvement in gas exchange.