Comparison Volume-controlled Ventilation, Pressure-controlled Volume-guaranteed Ventilation, and Pressure-controlled Ventilation During Gynecologic Laparoscopic Surgery in the Steep Trendelenburg Position

Objective: This study aimed to compare the effects of three different mechanical ventilation modes-Volume-Controlled Ventilation (VCV), Pressure-Controlled Ventilation (PCV), and Pressure-Controlled Volume-Guaranteed Ventilation (PCV-VG)-on pulmonary and hemodynamic variables during laparoscopic gynecologic surgery in the steep Trendelenburg position. The hypothesis was that PCV and PCV-VG would be superior to VCV in optimizing respiratory mechanics and improving oxygenation, particularly by reducing peak inspiratory pressure (Ppeak). Methods: Prospective, randomized, controlled clinical trial. Sixty ASA I-III patients aged 20-65 years undergoing elective laparoscopic gynecologic surgery in the steep Trendelenburg position were included (20 patients per ventilation group). Patients were randomized into VCV, PCV, and PCV-VG groups. Intraoperative ventilation was performed with a tidal volume of 8 mL/kg, PEEP of 5 cmH2O, and intra-abdominal pressure maintained at 12-14 mmHg. Data were collected at four time points: T1 (after induction, supine), T2 (30 min after CO2 insufflation, Trendelenburg), T3 (60 min after pneumoperitoneum), and T4 (after CO2 deflation, supine). Primary outcome: Ppeak comparison between groups. Secondary outcomes: Dynamic lung compliance (Cdyn), mean inspiratory pressure (Pmean), gas exchange, and hemodynamic parameters.