Splanchnic circulation following coeliac plexus block.

Abstract

Both the capacitance vessels and the resistance vessels of the splanchnic area are innervated by the sympathetic nerve fibers. We investigated the effect of abdominal visceral sympathectomy on splanchnic circulation, and the effect of altered splanchnic circulation on systemic circulation in ten mongrel dogs. Abdominal visceral sympathectomy was induced by coeliac plexus block with 1 ml/kg (body weight) of 1% lidocaine infiltrated around the coeliac artery. Comparison was made with infiltration of physiologic saline of the same volume. The saline infiltration caused no significant changes in the hemodynamic parameters of systemic and splanchnic circulation. Mean arterial pressure decreased significantly from 18.2 +/- 2.0 to 14.4 +/- 1.9 kPa following the coeliac plexus block, with a concomitant decrease in the cardiac index from 2.63 +/- 0.46 to 2.30 +/- 0.54 l X min-1 X m-2, while systemic vascular resistance was unchanged. Portal vein blood flow, hepatic artery blood flow and, therefore, splanchnic blood flow decreased by 8 to 17%. Portal vascular and hepatic artery resistances were not affected by abdominal sympathectomy. It was concluded that the capacitance vessels in splanchnic circulation are dilated during abdominal sympathetic denervation, causing a blood shift from systemic to splanchnic circulation. On the other hand, the resistance vessels in splanchnic circulation are affected little by abdominal visceral sympathectomy.