Female pigs (n = 18, 20-25 kg) underwent
laparotomy, during which ultrasonic flow probes were placed on the portal vein and the common hepatic artery.
Catheters were inserted in the superior mesenteric and left hepatic veins. After 5 days, all animals were anesthetized and 12 of them received 40% total body surface area third-degree
burn; 100 microg/kg Escherichia coli
lipopolysaccharide (LPS) was intravenously administered 18 hours postburn. Burned animals were randomized to receive a constant infusion of
iloprost (20 ng/kg per minute) or an equivalent amount of carrier
solution (
normal saline). All animals were studied for 42 hours.
RESULTS:
Burn caused a 2.5-fold increase in hepatic arterial vascular resistance (HAVR) and a 39% decrease in hepatic arterial blood flow (HABF). Postburn administration of
iloprost did not improve the hepatic arterial hemodynamics (1.8-fold increase in HAVR and 38% decrease in HABF). Post-LPS, HABF was significantly reduced to 22% of baseline and HAVR was 15-fold increased (P < 0.05 vs. baseline, ANOVA). In contrast,
iloprost-treated animals did not show hepatic arterial vasoconstriction, as both HABF and HAVR remained baseline values during the endotoxic phase (P < 0.05 vs. nontreated group, ANOVA). Postburn
iloprost treatment yielded a significant improvement in post-LPS portal venous blood flow (PVBF, 79% of baseline vs. 45% of baseline in nontreated animals, P < 0.05, ANOVA). Portal venous pressure showed 16% and 56% increases after
burn and
endotoxin, respectively.
Portal hypertension did not occur in
iloprost-treated animals, as portal venous pressure remained within baseline range (P < 0.05 vs. nontreated group, ANOVA).
Burn and
endotoxemia resulted in a significant decrease of hepatic
oxygen delivery (hDO2, 63% and 12% of baseline, respectively) and hepatic oxygen consumption (hVO2, 61% and 21% of baseline, respectively). Only during the postburn endotoxic phase,
iloprost improved hDO2 and hVO2 (140% and 79%, respectively; P < 0.05 vs. nontreated group, ANOVA).
CONCLUSIONS: