ARDS in the perioperative period of cardiac surgery: predictors, diagnosis, prognosis, management options and future directions

ABSTRACT Acute Respiratory Distress Syndrome (ARDS) after cardiac surgery is reported with a widely variable incidence (from 0.4 to 8.1%). Cardiac surgery patients are usually affected by several comorbidities, and the development of ARDS significantly impact on their prognosis. We summarize evidence regarding the current knowledge in the field of ARDS in cardiac surgery, followed by the discussion on therapeutic strategies considering the peculiar aspects of ARDS after cardiac surgery. Prevention of lung injury during and after cardiac surgery remains pivotal. Blood product transfusions should be limited to minimize -among others- the risk of lung injury. Open-lung ventilation strategy (ventilation during cardiopulmonary bypass, recruitment manoeuvres and use of moderate positive end-expiratory pressure) has not shown clear benefits on clinical outcomes. Intra- and post-operative ventilatory settings should carefully consider the impact of mechanical ventilation on cardiac function (in particular the right ventricle). Driving pressure should be kept as low as possible, with low tidal volumes (on predicted body weight) and optimal positive end-expiratory pressure. Regarding the therapeutic options, management of ARDS after cardiac surgery challenges the common approach. For instance, prone position may not be easily applicable after cardiac surgery. In patients developing ARDS after cardiac surgery, extracorporeal techniques may be a valid choice in experienced hands. The use of neuromuscular blockade and inhaled nitric oxide can be considered case by case, while use of aggressive lung recruitment and oscillatory ventilation should be discouraged.