Effects of portacaval shunt and hepatic artery ligation on liver surface oxygen tension and effective hepatic blood flow.

Liver surface oxygen tension (LSOT) and nutrient hepatic blood flow (NHBF) were measured in rats 1 hr and 1 week after sham operation, portacaval shunt (PCS), and hepatic artery ligation (HAL). LSOT was measured using a heated Clark electrode (37 deg) and was expressed as percentage of rectus muscle O2 tension to correct for changes in systemic oxygenation. Nutrient hepatic blood flow (NHBF) was measured using steady-state, low-dose galactose clearance pharmacokinetics. Acutely, we found a close correlation between LSOT and nutrient hepatic blood flow after both hepatic artery ligation and portacaval shunt. At one week after hepatic artery ligation, LSOT and nutrient hepatic blood flow made parallel increases. However, 1 week after portacaval shunt, LSOT increased while nutrient hepatic blood flow remained reduced. The divergence in these results between the two methods of producing hepatic hypoperfusion, implies that LSOT recovers via a different mechanism after portacaval shunt. Recovery of LSOT at one week probably reflects normalization of hepatic O2 delivery after hepatic artery ligation and impaired oxygen utilization after portacaval shunt.