Changes in hepatic venous oxygen saturation in hepatic warm ischemia/reperfusion injury in pigs

To clarify the changes that occur in hepatic venous oxygen saturation (Shvo (2)) during hepatic ischemia/reperfusion (I/R) injury, we examined the rela tionship between Shvo(2), hepatic tissue blood how (HTBF), and portal vein pressure (PVP) in a warm I/R model using pig livers. Female pigs weighing 1 8-23 kg were subjected to warm I/R under extracorporeal circulation between the superior mesentric vein and the left jugular vein to avoid portal cong estion., The warm ischemic times were 120 min (n = 4), 180 min (n = 14), an d 240 min (n = 4). Shvo(2), HTBF, and PVP were measured after reperfusion. The survival rates of the pigs 3 days after reperfusion were 100% in the 12 0-min group, 57% in the 180-min group, and 25% in the 240-min group. In the 180-min group, the Shvo(2) was lower in the pigs that died than in those t hat survived. There was a significant correlation between Shvo(2) and both PVP and HTBF after reperfusion. Histological examination revealed findings of severe I/R injury in pigs with a low Shvo(2), and mild I/R injury in pig s with a stable Shvo(2). These observations suggest that the changes in Shv o(2) could reflect the degree of hepatic I/R injury, especially that relate d to microcirculatory disturbances occurring at the sinusoid levels.