Risk factors for pulmonary complications after hepatic resection: role of intraoperative hemodynamic instability and hepatic ischemia

BACKGROUND Postoperative operative pulmonary complications (PPCs) after hepatic surgery are associated with increased length of hospital stays. Intraoperative blood transfusion, extensive resection and different comorbidities have been identified. Other parameters, like time of hepatic ischemia, have neither been clinically studied, though experimental studies show that hepatic ischemia can provide lung injury. The objective of this study was to determinate the risk factors of postoperative pulmonary complications (PPCs) after hepatic resection within 7 postoperative days. METHOD Ninety-four patients consecutively who underwent elective hepatectomy between January and December 2013. Demographic data, pathological variables, and preoperative, intraoperative, and postoperative variables had been prospectively collected in a data base. The dependant variables studied were the occurrence of PPCs, defined before analysis of the data. RESULTS PPCs occurred in 32 (34%) patients. A multivariate analysis allowed identifying the risk factors for PPCs. On multivariate analysis, preoperative gamma-glutamyltransferase (GGT) elevation OR =5,12 [1,85-15,69] p = 0,002, liver ischemia duration OR = 1,03 [1,01-1,06] p = 0,01 and the intraoperative use of vasopressor OR = 4,40 [1,58-13,36] p = 0,006 were independently associated with PPCs. For every 10 min added in ischemia duration, the OR of the risk of PPCs was estimated to be 1.37 (CI95% = [1.08-1.81], p = 0.01). CONCLUSION Three risk factors for PPCs have been identified in a population undergoing liver resection: preoperative GGT elevation, ischemia duration and the intraoperative use of vasopressor. PPCs after liver surgery could be related to lung injury induced by liver ischemia reperfusion and not solely by direct infectious process. That could explain why factors influencing directly or indirectly liver ischemia were independently associated with PPCs.