Abstract
We evaluated the effect of reduced blood pressure by trimetaphan (TMP), PGE1 and thoracic epidural block (TEB) on portal venous oxygenation in patients with hypertension during gastrectomy. The patients studied were divided into three groups: a TMP group (n=7), PGE1 group (n=7), and TEB group (n=7). Catheterization of the portal vein via the umbilical vein was performed for portal blood sampling. Mean arterial blood pressure was reduced to 70% of the pre-treatment value. A significant but small decrease in CaO2 was observed after administration of vasodilators or TEB. In the TMP and TEB groups, portal venous PO2 (PPVO2) and CO2 (CPVO2) were significantly reduced and CaO2-CPVO2 was significantly increased with reduced blood pressure, probably due to the decrease in portal venous blood flow. However, no significant changes in PPVO2, CPVO2 or CaO2 -CPVO2 were obseved in the PGE1 group, suggesting that portal venous blood flow is maintained by reduced blood pressure with PGE1. Careful attention is needed to ensure that hypotension induced by TMP or TEB does not reduce the oxygen supply to the liver.
