Mechanical ventilation and cardiopulmonary bypass: a narrative review of the mechanistic lung protective measures

Abstract

Postoperative pulmonary dysfunction is a multifactorial complication in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). Numerous risk factors including individual, surgery- and anesthesia-related have been identified. Exacerbated systemic and pulmonary inflammatory response to CPB is one of the most studied mechanisms of lung injury in this patient setting. However, current literature lacks specific intraoperative mechanical ventilation (MV) strategies associated with a significant improvement in patients’ outcomes. We reviewed the randomized clinical trials and other reports published within the last 5 years involving patients undergoing cardiac surgery with CPB in order to summarize the existing MV strategies used in these patients and their associated outcomes. Moreover, we described the pathophysiological mechanisms involved in post- CPB lung injury and the mechanistic effects of protective ventilation.