VC-AF vs FCV in Obese Patients Undergoing Laparoscopic Surgery

Obesity adversely affects respiratory physiology by reducing lung volumes and compliance and increasing airway resistance and alveolar collapse. These effects are further aggravated by pneumoperitoneum during laparoscopic surgery, increasing the risk of impaired oxygenation and ventilator-induced lung injury (VILI). Mechanical power (MP) reflects the total energy transferred to the respiratory system during mechanical ventilation and is influenced by tidal volume, respiratory rate, airway pressures, flow, and PEEP. Increased airway and driving pressures may contribute to higher mechanical power and lung injury, particularly in obese patients undergoing laparoscopic surgery. This study aims to compare flow-controlled ventilation (FCV) and volume-controlled ventilation with autoflow (VC-AF) in obese patients undergoing laparoscopic surgery in terms of airway pressures, driving pressure, and mechanical power. The investigators hypothesize that FCV may reduce airway pressures, driving pressure, and mechanical power compared with VC-AF, potentially decreasing the risk of VILI. The effect of FCV on oxygenation will also be evaluated as a secondary outcome.

Inclusion Criteria: Age ≥18 years Body mass index (BMI) ≥30 kg/m² American Society of Anesthesiologists (ASA) Physical Status I-III Scheduled to undergo elective laparoscopic surgery under general anesthesia Exclusion Criteria: Pregnancy Emergency surgery Presence of a cardiac pacemaker Chronic obstructive pulmonary disease (COPD)