The goal of this clinical trial is to compare the effects of flow-controlled ventilation (FCV) and volume-controlled ventilation (VCV) on hemodynamic and respiratory parameters in obese patients undergoing elective laparoscopic bariatric surgery. The main questions it aims to answer are:
Does FCV provide better intraoperative hemodynamic and respiratory stability compared to VCV during laparoscopic bariatric surgery? Is FCV a safe and feasible ventilation strategy under high intraabdominal pressure and position changes required in bariatric surgery?
Researchers will compare FCV group to VCV group to see if FCV improves intraoperative respiratory mechanics and hemodynamic parameters.
Participants will:
Undergo elective laparoscopic bariatric surgery with BMI \>40 kg/m² (ASA I-III) Receive either flow-controlled or volume-controlled ventilation with individualized PEEP and tidal volume of 6-8 ml/kg predicted body weight Have intraoperative hemodynamic and respiratory parameters monitored at regular intervals, including arterial blood gas analysis Be followed postoperatively for oxygen therapy requirement and intensive care need
Age between 18 and 65 years American Society of Anesthesiologists (ASA) physical status I, II, or III Body Mass Index (BMI) ≥ 40 kg/m² Scheduled for elective laparoscopic bariatric surgery Willing to participate in the study
ASA physical status IV or V Emergency surgical procedures Pregnant patients Patients requiring vasopressor support to maintain mean arterial pressure above 65 mmHg intraoperatively Patients with advanced pulmonary disease Patients who decline to participate in the study
Adult morbidly obese patients (BMI ≥40 kg/m²) aged 18-65 years, classified as ASA I-III, scheduled for elective laparoscopic bariatric surgery at Ankara Training and Research Hospital.
Cohort
Other
Flow-Controlled Ventilation (FCV)
DevicePatients were ventilated using flow-controlled ventilation with a tidal volume of 6-8 ml/kg predicted body weight. PEEP was individualized based on respiratory compliance following CO₂ insufflation.
Volume-Controlled Ventilation (VCV)
DevicePatients were ventilated using volume-controlled ventilation with a tidal volume of 6-8 ml/kg predicted body weight. PEEP titration was performed in eligible patients.
Intraoperative Respiratory Mechanics
Comparison of driving pressure between FCV and VCV groups at defined intraoperative time points.
Mean Arterial Pressure
Comparison of mean arterial pressure (MAP) between FCV and VCV groups at defined intraoperative time points.
Pa02/Fi02 ratio
Comparison of Horowitz index between FCV and VCV groups.
Postoperative Oxygen Theraphy Need
Comparison of percentage of participants requiring postoperative oxygen therapy requirement between FCV and VCV groups.
Postoperative Intensive Unit Admission
Comparison of the number of patients requiring admission to the intensive care unit between the FCV and VCV groups.
Arterial Partial Pressure of Carbon Dioxide (PaCO2)
Comparison of arterial partial pressure of carbon dioxide (PaCO2) between the FCV and VCV groups to evaluate efficiency of carbon dioxide elimination at defined time points.
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