Consequences of Pneumoperitoneum on Liver Ischemia During Laparoscopic Portal Triad Clamping in a Swine Model

Abstract

Portal triad clamping (PTC) may be required during laparoscopic liver resection to limit blood loss. The aim of this study was to test in a swine model the hypothesis that during laparoscopic PTC, increased intraperitoneal pressure may alter hepatic vein reverse circulation, inducing a more severe hepatic ischemia compared with PTC performed in laparotomy. Fifteen pigs were randomized into three groups: laparoscopy (1 h of pneumoperitoneum at 15 mmHg and 3 h of surveillance), open PTC (1 h PTC through laparotomy and 3 h of reperfusion), and laparoscopic PTC (1 h PTC with 15 mmHg pneumoperitoneum and 3 h of reperfusion). PTC was performed under mesenteric decompression using a veno-venous splenofemoral bypass. Hepatic partial oxygen tension and microcirculatory flow were continuously measured using a Clarke-type electrode and a laser Doppler flow probe, respectively. Liver consequences of PTC was assessed by right atrium serum determination of transaminases, creatinine, bilirubin, INR, and several ischemia/reperfusion parameters, drawn before PTC (T0), before unclamping (T60), and 1 (T120) and 3 h after reperfusion (T240). Histology was performed on T240 liver biopsies. Compared with open PTC, laparoscopic PTC produced a more rapid and more severe decrease in hepatic oxygen tension, indicating a more severe tissular hypoxia, and a more severe decrease in hepatic microcirculatory flow, indicating a decrease in hepatic backflow. At T240, the laparoscopic PTC livers suffered from a higher degree of hepatocellular damage, shown by higher transaminases and increased necrotic index at pathology. These results indicate that in this pig model, laparoscopic PTC induces a more severe liver ischemia, related to decreased hepatic oxygen content and decreased hepatic backflow. If confirmed by clinical studies, these results may indicate that caution is necessary when performing prolonged PTC during laparoscopic hepatic resection, particularly in cirrhotic or steatotic livers.