[Effect of acebutolol on plasma catecholamines and perioperative endocrine stress parameters]

In order to investigate the effect of intraoperative beta-blockade with acebutolol on the endocrine stress response during modified neuroleptanesthesia, 20 patients for major abdominal or thoracic surgery from ASA groups I-III were randomly allocated to the following groups: (1) control group without acebutolol treatment; or (2) treatment group, administration of 0.2 mg/kg acebutolol 5 min after induction of anesthesia. During a period of 30 min before operation, intraoperatively, and 30 min after the end of operation plasma levels of norepinephrine and epinephrine (by HPLC) and ADH, ACTH, and cortisol (by RIA) were measured. In addition, mean arterial pressure (MAP), HR, and plasma concentrations of glucose, lactate, and free glycerol were determined. Statistical evaluation was undertaken by analysis of variance with repeated measures on one factor, considering P values of less than 0.05 as significant. The administration of acebutolol had no influence on plasma catecholamine concentrations during the preoperative rest period. There was no evidence of any interaction between beta-blockade and plasma catecholamines. After induction of anesthesia, the levels of all hormones decreased. During the operation, there was a significant increase in all endocrine parameters measured. No differences were found between the treatment and control groups. All endocrine parameters reached their highest levels 30 min after the end of the operation. The differences in MAP, HR, glucose, lactate, and free glycerol between the groups failed to reach statistical significance.