Effect of increased intra-abdominal pressure on liver histology and hemodynamics: An experimental study

Background: While reduction of portal venous (PV) blood flow has been described in animal models of intra-abdominal hypertension, reports on compensatory changes in hepatic arterial (HA) flow, known as the hepatic arterial buffer response are controversial. Materials and Methods: Pneumoperitoneum with helium was induced in 13 piglets. Hemodynamic measurements and pathological assessment were conducted at baseline and during the three subsequent phases: Phase A: 45 minutes with a stable intraabdominal pressure of 25 mmHg; phase B: 45 minutes with a stable intra-abdominal pressure of 40 mmHg; and phase C during which the abdomen was re-explored and reperfusion of the liver was allowed to take place. Results: Phase B pressure was significantly greater than phase A pressure in both the PV and the inferior vena cava, demonstrating a positive association between escalating intra-abdominal hypertension and the pressure in these two vessels (all p<0.001). In contrast, HA pressure was comparable between baseline and phase A, while it tended to decrease in phase B. Regarding histology, the most notable abnormality was the presence of inflammatory infiltrates and hepatocyte necrosis. Conclusion: Helium-insufflation increased PV pressure with a partial compensatory decrease of HA pressure. Nonetheless, findings consistent with hepatic ischemia were observed on pathology.