The effects of external oblique fascial plane block and subcostal transversus abdominis plane block on postoperative pulmonary functions in patients undergoing laparoscopic cholecystectomy

Zeynep Gürbüz, The Effects of External Oblique Fascial Plane Block and Subcostal Transversus Abdominis Plane Block on Postoperative Pulmonary Functions in Patients Undergoing Laparoscopic Cholecystectomy, Zonguldak Bülent Ecevit University Faculty of Medicine, Department of Anesthesiology and Reanimation, Specialization Thesis in Medicine, 2025 Aim: The primary outcome is to investigate the effects of external oblique fascial plane block (EOIPB) and subcostal transversus abdominis plane (TAP) block on postoperative pulmonary functions in patients undergoing laparoscopic cholecystectomy. Secondary outcomes include the evaluation of postoperative pain scores, opioid consumption, and quality of recovery. Materials and Methods: A total of 102 patients aged 18–65 years and classified as ASA physical status I–III, scheduled for elective laparoscopic cholecystectomy, were enrolled in the study. Patients were randomly assigned to three groups: Subcostal group (n=34), EOIPB group (n=34), and Control group (n=34). After accounting for dropouts, data from 90 patients (30 in each group) were analyzed. Preoperative spirometry (SFT) was performed, and following general anesthesia and block administration, intraoperative hemodynamic data and opioid consumption were recorded. Postoperative SFT values, opioid consumption, pain scores, and QoR-15 scores were documented. Results: At postoperative hour 1, FVC, FEV₁, predicted FEV₁, and PEF values were significantly lower in the Control group compared to both block groups, with the highest values observed in the EOIPB group. At 6 and 24 hours, FVC and FEV₁ values were significantly better preserved in the EOIPB group than in the Control group. Although predicted FEV₁ was higher in the EOIPB group at hour 1, no significant differences were found between the EOIPB and Subcostal groups in most parameters. Both rest and dynamic NRS pain scores were significantly higher in the Control group at all time points, whereas there were no significant differences between the block groups. Postoperative opioid consumption was significantly lower in both the Subcostal and EOIPB groups compared to the Control group. QoR-15 scores were also significantly higher in both block groups than in the Control group. Conclusion: Both subcostal TAP and EOIPB blocks were found to be effective and safe in preserving postoperative pulmonary function, improving pain control, and reducing opioid requirements. Both blocks contributed to enhanced early postoperative recovery following laparoscopic cholecystectomy. Keywords: External Oblique Fascial Plane Block, Subcostal Transversus Abdominis Plane Block, Postoperative Pulmonary Function, Opioid Consumption, Quality of Recovery