Anæsthesia in operations for the relief of portal hypertension

The pressure in the portal vein in health varies between about 40mm and 210mm waterl.Raised pressure in the system may result from obstruction to the vein as its branches ramify in the liver, as in cirrhosis, or from extra-hepatic causes.These include congenital portal vein obliteration, thrombosis from trauma or infection, compression or invasion by abdominal neoplasm, right heart failure and constrictive pericarditis.The net effect of all these conditions is the same, namely slowing or reversal of flow in the portal system and a natural attempt at by-pass and reduction of pressure by increased flow through the portal-systemic anastomoses.These are numerous, but the most important are those in the lower esophagus and upper stomach.Varices developing in this situation may erode and rupture, with severe and sometimes fatal hzmatemesis.Such bleeding and melzna apart, presenting symptoms and signs may be anaemia, splenomegaly, ascites, jaundice or stupor.