A Prospective Randomized Study of Effect if Lung Protective Ventilation by Reducing Airway Pressure During Laparoscopic Surgery

Anaesthesiologists have been ventilating patients in the perioperative period with relatively large tidal volumes (10-15 ml/kg ideal body weight) to prevent intraoperative atelectasis. Ventilating patient with large tidal volumes may be a risk factor for development of lung injury.During surgical procedures, both general anesthesia and high tidal volumes may strain non injured lungs and trigger inflammation. High tidal volumes that cause alveolar overstretching can contribute to extra pulmonary organ dysfunction through systemic release of inflammatory mediators.

Recently protective lung ventilation strategies has been reported to be useful to reduce the respiratory complications in postoperative period. The use of small tidal volume (Vt), positive end-expiratory pressure (PEEP) and restricting peak airway pressure have shown reduced incidence of ventilation induced lung injury.

It has been shown that a small tidal volume (VT) and PEEP can reduce the incidence of postoperative lung dysfunction and improve intraoperative oxygenation. Restricting peak airway pressure can be achieved by inverse ratio ventilation. Minimizing the risk of ventilator-induced lung injury (VILI), improving oxygenation and alveolar recruitment are all advantages of inverse ratio ventilation. However, the potential utility of pressure controlled inverse ratio ventilation (PCIRV) has not been studied in patients undergoing general anaesthesia.

Investigators hypothesized that in patients with normal lungs scheduled for general anesthesia, PIV might prevent lung function deterioration and lung morphological alterations. Investiagators aim was to compare the intraoperative protective ventilation strategies on oxygenation/ ventilation and postoperative lung dysfunction and lung injury among patients undergoing laparoscopic upper abdominal surgery.