The influence of spinal sympathetic blockade upon local regulation of blood flow in subcutaneous adipose tissue was investigated in six subjects. The effect of changes in orthostatic pressure on blood flow in subcutaneous tissue in the crus and distal forearm was measured before and after sympathetic blockade obtained by epidural anesthesia in 4 subjects and by a bilateral sympathectomy in 2 patients suffering from manual hyperhidrosis. Blood flow in subcutaneous tissue measured by 133Xe washout technique decreased by about 40 per cent when the limb was lowered, and remained constant during 30 cm elevation. This was found both before and after the blockade, though in one of the patients, the orthostatic decrease in blood flow was less pronounced 24 h after sympathectomy. Hence central sympathetic reflexes do not alter local orthostatic changes of blood flow in subcutaneous tissue. These changes therefore are most likely due to local mechanisms.

In 19 patients with cirrhosis of the liver and portal hypertension, a catheter was inserted into the portal vein using a percutaneous transhepatic technique. The portal pressure was measured during general anaesthesia with and without halothane, and in the awake state. Addition of halothane to the N2O:O2 anaesthesia did not change portal venous pressure, in spite of a significant fall in arterial blood pressure. Portal venous pressure under general anaesthesia with complete muscle relaxation did not differ from the pressure in the resting, awake patient.