Vascular changes
PASP was found to be elevated in several studies, presumably due to hypoxemia-mediated pulmonary vasoconstriction, pulmonary emboli and the effects of positive pressure ventilation[18,22–25]. Notably, there has also been a high incidence of deep venous thrombosis among COVID-19 patients. A recent meta-analysis highlighted an overall incidence of 20% which is disproportionately high when compared to patients admitted for other medical conditions[34]. A recent study also described a high rate of fluid responsiveness (82.9% of patients) based on an inferior vena cava (IVC) distensibility index >18% at the time of evaluation. This was thought to be due to third spacing of fluids because of sepsis, reduction of venous return to the RV due to high positive pressure ventilation and a natural tendency to maintain a negative fluid balance in patients with ARDS[18].