Microcirculatory alterations are associated with pulmonary dead-space fraction in moderate and severe ards

Introduction Shunt-induced hypoxemia is considered the primary pathophysiological abnormality and main diagnostic criteria of acute respiratory distress syndrome (ARDS). However, increases in dead-space ventilation (VD/VT) can also contribute to gas exchange alterations in ARDS. Systemic microcirculatory alterations described during inflammatory conditions are characterized by perfusion heterogeneity and theoretically pulmonary microcirculatory heterogeneity could lead to imbalance pulmonary ventilation/perfusion relationship. Thus, we hypothesized that systemic microvascular alterations could reflect increased VD/VT in ARDS.