‘The Right Ventricle in Acute Respiratory Distress Syndrome’

Acute respiratory distress syndrome is associated with poor clinical outcomes with a pooled mortality rate of approximately 40% despite best standards of care. Current therapeutic strategies are based upon improving oxygenation and pulmonary compliance while minimizing ventilator induced lung injury. It has been demonstrated that relative hypoxemia can be well tolerated and improvements in oxygenation do not necessarily translate into survival benefit. Cardiac failure, in particular right ventricular dysfunction, is commonly encountered in moderate to severe acute respiratory distress syndrome and is reported to be one of the major determinants of mortality. The prevalence rate of echocardiographically evident right ventricular dysfunction in acute respiratory distress syndrome varies across studies ranging from 22% to 50%. Although there is no definitive causal relationship between right ventricular dysfunction and mortality, severe right ventricular dysfunction is associated with increased mortality. Factors that can adversely affect right ventricular function include hypoxic pulmonary vasoconstriction, hypercapnia, and invasive ventilation with high driving pressure. It might be expected that early diagnosis of right ventricular dysfunction would be of benefit however, echocardiography markers (qualitative and quantitative) used to prospectively evaluate the right ventricle in acute respiratory distress syndrome have not been tested in adequately powered studies. In this review we examine the prognostic implications and pathophysiology of right ventricular dysfunction in acute respiratory distress syndrome and discuss available diagnostic modalities and treatment options. We aim to identify gaps in knowledge and directions for future research that could potentially improve clinical outcomes in this patient population.