Clinical significance of postoperative cardiothoracic ratio for postoperative pleural effusion following hepatectomy

Abstract Background: Although several preoperative risk factors for postoperative pleural effusion (POPE) after hepatectomy have been reported, few postoperative predictors have been investigated. We aimed to examine risk factors for clinically relevant POPE (CR-POPE) and whether cardiothoracic ratio (CTR) could be a predictive factor. Methods: Participants in this retrospective investigation comprised 382 patients who underwent hepatectomy between January 2012 and December 2021. Perioperative characteristics that were considered potential risk factors for CR-POPE were evaluated. CR-POPE was defined as having undergone thoracentesis or thoracic drain placement. Results: Patients were divided into a CR-POPE group (n = 38; 10.0%) and a non-CR-POPE group (n = 344; 90.0%). The CR-POPE group showed significantly higher intraoperative infusion volume (P < 0.001) and lower intraoperative urine volume (P = 0.015). In multivariate analysis, abdominal incision with a reversed L-shape or inverted T-shape (odds ratio [OR] = 3.07, P = 0.023], estimated blood loss >772 g (OR = 2.71, P = 0.049), diaphragm incision (OR = 8.31, P = 0.008), major postoperative complications excluding CR-POPE (OR = 7.99, P < 0.001), intraoperative infusion volume per body weight > 80 mL/kg (OR = 4.80, P = 0.007) and CTR on postoperative day (POD)1 >59.0% (OR = 4.34, P = 0.001) were all independently associated with occurrence of POPE. Conclusion: We clarified risk factors for CR-POPE following hepatectomy. The occurrence of CR-POPE might be predictable from the CTR on POD1.