al Lung protective ventilation in Cardiac Surgery

Multicenter, randomized, controlled trials and meta-analyses have demonstrated that, during abdominal surgery, protective ventila-tion, based on low tidal volumes, positive end-expiratory pressure, and recruitment maneuvers improves postoperative outcomes (1). Protective ventilation strategies are aimed at preventing alveolar over-distension, cyclic opening and closure of peripheral airways, trans-pulmonary pressure related lung stress, recruitment and de-recruitment of lung units, and local and systemic release of in-flammatory mediators. Barotrauma, volutrama, and atelectrauma are all involved in ventilator induced lung injury, and it is gen-erally accepted that protective ventilation, delivered in patients with injured lungs (acute respiratory distress syndrome), increas-es patients ’ survival (2, 3). It is also of note that non-injured lungs (e.g. those undergoing elective surgery) may suffer from ventilator induced lung injury independently of an underlying pulmonary or extra-pulmonary disease. General anesthesia reduces muscu-lar tone and alters diaphragmatic position promoting reduction in lung volume, alteration in ventilation/perfusion ratio, and the onset of lung atelectasis, all of which are strong predictors of pul-monary complications. Hence, mechanical ventilation is an in-jurious procedure. Its effects depend on intensity, duration and underlying predisposing factors. In light of this, patients under-going cardiac surgery are particularly sensitive to lung damage for several reasons: mechanical ventilation may be long lasting, co-morbidities are frequently present, and pro-inflammatory co-factors (cardiopulmonary bypass, transfusions, ischemia/reperfu-E di to r