[Antidiuretic hormone in peridural anesthesia with 0.5% bupivacaine. The effect of severe blood loss on ADH release].

14 patients scheduled for peripheral vascular surgery received epidural anaesthesia with bupivacaine 0.5%. Blood samples were obtained preoperatively (twice), intraoperatively (9 times) and postoperatively (3 times) for analysing the following parameters: 1. antidiuretic hormone (ADH, arginine-vasopressin) 2. serum electrolytes (potassium, sodium) 3. plasma osmolality In three patients unexpected sudden blood loss occurred, accompanied by typical haemodynamic changes. Pre- and intraoperative ADH-levels were normal with a slight increase at the end of the operative procedure. Electrolytes and osmolality in serum/plasma stayed within the normal range during the whole investigation period. In three patients suffering from shock due to unexpected blood loss ADH-levels rose excessively. The data demonstrate the well-known stress-attenuation under EDA as well as an increase of ADH-secretion in haemodynamic alteration.