Comparison of Pressure and Volume-Controlled Mechanical Ventilation in Laparoscopic Bariatric Surgery: A Randomized Crossover Trial

BACKGROUND: The number of patients with obesity undergoing various surgeries is increasing annually, and ventilation problems are highly prevalent in these patients. OBJECTIVES: We aimed to evaluate ventilation effectiveness with pressure-controlled (PC) and volume-controlled (VC) ventilation modes during laparoscopic bariatric surgery. METHODS: In this open-label randomized crossover clinical trial, 40 adult patients with morbid obesity candidates for laparoscopic bariatric surgery were assigned to VC-PC or PC-VC groups. Each patient received both ventilation modes sequentially for 15 min during laparoscopic surgery in a random sequence. Every 5 min, exhaled tidal volume, peak and mean airway pressure, oxygen saturation, heart rate, mean arterial pressure, and end-tidal CO(2) were recorded. Blood gas analysis was done at the end of 15 min. Dynamic compliance, PaO(2)/FiO(2) ratio, P (A-a) O(2) gradient, respiratory dead space, and PaCO(2)-ETCO(2) gradient were calculated according to the obtained results. RESULTS: The study included 40 patients with a mean age of 35.13 ± 9.06 years. There were no significant differences in peak and mean airway pressure, dynamic compliance, and hemodynamic parameters (P > 0.05). There was no significant difference between the two ventilation modes in pH, PaCO(2), PaO(2), PaO(2)/FIO(2), dead space volume, and D (A-a) O(2) at different time intervals (P > 0.05). CONCLUSIONS: If low tidal volumes are used during adult laparoscopic bariatric surgery, mechanical ventilation with PC mode is not superior to VC mode.