Protective ventilation strategies in cardiovascular surgery

Abstract

Introduction: The alteration in gas exchange is a complication of cardiac surgery with extracorporeal circulation. The cause of this deterioration is multifactorial. During the shunt, both lungs collapse and at the end of the extracorporeal circulation the lungs expand again, without a standard technique for it. The application of alveolar recruitment during general anesthesia in this type of surgery improves arterial oxygenation. Multiple strategies are used and have as a reference the extracorporeal circulation and its contribution to the pulmonary and systemic inflammatory response. This forces the anesthesiologist to understand the pathophysiology of lung injury associated with mechanical ventilation.

Objective: Describe essential aspects of pathophysiology of pulmonary injury associated with mechanical ventilation in cardiac surgical procedures and the effect of perioperative protective mechanical ventilation as a strategy to prevent it.

Method: A search of the literature published during the period between January 1990 and December 2020 was carried out that referred to protective mechanical ventilation strategies in cardiovascular surgery.

Results: Experimental and clinical evidence suggest that low current volumes of pulmonary ventilation and the application for a short period of increased inspiratory pressures, known as "recruitment maneuvers" followed by the application of positive pressure at the end of expiration to keep the recruited alveoli open, increase functional residual capacity and reduce lung injury associated with mechanical ventilation. These recommendations have been extrapolated from retrospective studies conducted in other types of populations.

Conclusions: There is no strong evidence that this strategy decreases the pro-inflammatory response, improves postoperative lung function and decreases perioperative mortality, when compared to conventional ventilation.

Keywords: Anesthesia; cardiovascular surgery; protective ventilation.