The use of intraoperative bedside lung ultrasound in optimizing Positive End Expiratory Pressure in obese patients undergoing laparoscopic bariatric surgeries.

Abstract Background Anesthetic management of patients with obesity undergoing laparoscopic abdominal surgeries requires careful plan for intraoperative mechanical ventilation aiming to avoid lung atelectasis and/or overdistension. There are conflicting data on the optimum positive end expiratory pressure (PEEP) during these surgeries. We hypothesized that lung ultrasound could be used for PEEP titration during laparoscopic surgery. Objective The purpose of this study is to evaluate the effectiveness of intraoperative individualized lung ultrasound-guided PEEP in obese patients undergoing laparascopic bariatric surgery on intraoperative partial arterial oxygen tension (PaO2) and early postoperative pulmonary complications. Methods A randomized controlled trial included 40 adult patients with body mass index > 35 kg/m2 undergoing laparascopic bariatric surgery. Patients were randomized into: control group (n=20) who received PEEP 4 cm.H2O and ultrasound-guided group (n=20) who received individualized lung ultrasound stepwise PEEP. All patients received volume-controlled ventilation with a tidal volume of 6 mL/kg of ideal body weight and a fraction of inspired oxygen of 0.5. The primary outcome was the difference in partial arterial oxygen tension (PaO2) between the control group and the ultrasound-guided group. The secondary outcomes included the incidence of early postoperative pulmonary atelectasis, respiratory failure, bronchospasm, hypoxia or pneumothorax. Settings general surgery operating theatre at Cairo University hospitals. Results Ultrasound-guided group showed higher PO2 after PEEP optimization and postoperatively compared to control group (p=0.005, and p=0.01 respectively). Also, Ultrasound-guided group showed no postoperative complications compared to control group that had five cases who developed postoperative pulmonary complications in the form of hypoxia and basal collapse in the first 24 hour postoperatively chest x ray (0% versus 25%, p=0.047). Conclusion In patients with obesity undergoing laparoscopic bariatric surgery, the use of lung ultrasound individualized stepwise PEEP approach improved oxygenation, compliance and reduced the incidence of postoperative pulmonary atelectasis and hypoxia without causing hemodynamic instability.