Preoperative Diaphragmatic Excursion and Postoperative Pulmonary Complications After Laparoscopic Sleeve Gastrectomy:...

Background and Objectives: Postoperative pulmonary complications (PPCs) remain clinically relevant after bariatric surgery, while conventional risk assessment provides limited direct information on diaphragmatic performance. This study evaluated whether preoperative diaphragmatic excursion measured by ultrasonography was associated with European Perioperative Clinical Outcome (EPCO)-defined PPCs after laparoscopic sleeve gastrectomy (LSG) and whether it provided complementary discriminatory information beyond the Assess Respiratory Risk in Surgical Patients in Catalonia (ARISCAT) score. Materials and Methods: This retrospective observational cohort study included 128 adults who underwent primary elective LSG between May 2021 and March 2026. Preoperative bilateral diaphragmatic excursion was assessed by M-mode ultrasonography during quiet breathing and deep inspiration. The primary endpoint was occurrence of at least one EPCO-defined PPC during the index hospitalization. Associations were evaluated using parsimonious multivariable logistic regression, and discrimination was assessed using receiver operating characteristic analysis. Results: Seventy patients (54.7%) developed at least one PPC. Right deep inspiratory excursion showed the largest between-group difference (6.70 ± 0.4 cm in PPC-positive vs. 8.10 ± 0.6 cm in PPC-negative patients; p < 0.001). In the extended model, greater right deep inspiratory excursion was associated with lower odds of PPCs (adjusted OR per 1-cm increase 0.60, 95% CI 0.41-0.87; p = 0.007), while ARISCAT remained associated with PPC occurrence. ARISCAT alone yielded an area under the receiver operating characteristic curve (AUC) of 0.70 (95% CI 0.61-0.79), compared with 0.73 (95% CI 0.64-0.87) for right deep inspiratory excursion and 0.80 (95% CI 0.71-0.88) for the combined model. The combined model showed greater discrimination than ARISCAT alone (DeLong p = 0.03). In a sensitivity analysis excluding isolated minor atelectasis from the composite endpoint, the association remained directionally consistent but was no longer statistically significant (adjusted OR 0.75, 95% CI 0.48-1.02; p = 0.07). Conclusions: Lower preoperative diaphragmatic excursion was associated with EPCO-defined PPCs after LSG. Right deep inspiratory excursion may provide complementary physiological information to established clinical risk assessment, although prospective validation is required before routine clinical implementation.