Effect of Intraoperative Lung Recruitment and Transversus Abdominis Plane Block in Laparoscopic Bariatric Surgery on Postoperative Lung Functions: A Randomized Controlled Study

Background: Morbid obesity may cause a restrictive condition. General anesthesia (GA) and supine posture both decrease lung capacity and functional residual capacity (FRC), altering the ventilation/perfusion ratio and raising the pulmonary shunt.

Objectives: To evaluate the impact of recruitment maneuver (RM) and transversus abdominis plane (TAP) block performed during laparoscopic bariatric surgery on spirometry, oxygenation, opioid requirements, and pain score assessed after surgery.

Methods: This pilot prospective randomized controlled study included 80 patients scheduled for elective laparoscopic bariatric surgeries (e.g., laparoscopic sleeve gastrectomy and laparoscopic gastric bypass) under GA. Patients were divided into four equal groups. All patients received a standardized postoperative analgesia regimen. Group I (control group), group II received TAP block after intubation and before surgical incision, group III received RM after intubation and after pneumoperitoneal insufflation, and group IV received RM after intubation and after pneumoperitoneal exsufflation and TAP block after intubation and before surgical incision.

Results: Forced vital capacity (FVC) and forced expiratory volume (FEV1) were significantly higher after group IV operation than in other groups. Intraoperative PaO₂ and PaO₂/FiO₂ were significantly higher in groups III and IV compared to other groups. The numerical rating scale (NRS) at 1, 2, 4, 6, and 12h was significantly decreased in groups II and IV compared to other groups. Morphine consumption was significantly lower in groups II and IV compared to other groups.

Conclusions: TAP block combined with RM had better postoperative pulmonary function tests. Intraoperative oxygenation was higher in RM.