[Influence of caudal anesthesia on the secretion of catecholamines in children].

Eighty-two children, class ASA I, between four months and 14 years of age, all undergoing elective subumbilical surgery, were randomly assigned to two groups: a control "halothane anesthesia" group (n = 35) and a 0.25% bupivacaine "caudal anaesthesia" group (n = 47). In the control group, there was a significant peroperative increase in heart rate, respiratory rate, systolic blood pressure and plasma adrenaline levels (p less than 0.05). There was no significant difference in the noradrenaline levels. In the "caudal anaesthesia" group, the haemodynamic response was less pronounced, this being concomitant with a decrease in adrenaline and noradrenaline levels (p less than 0.05 and p less than 0.001, respectively). During surgery, there were significant differences between the groups in heart rate, respiratory rate, noradrenaline levels (3 +/- 0,30 nmol X l-1 vs 1.68 +/- 0.18 nmol X l-1; p less than 0.001) and adrenaline levels (1.67 +/- 0,28 nmol X l-1 vs 0.78 +/- 0.08 nmol X l-1; p less than 0.01). It is concluded that the catecholamine response in children undergoing minor abdominal surgery has been blocked by caudal anaesthesia.