Influence of premedication on plasma ACTH and cortisol concentrations in children during adenoidectomy

The endocrine response to stress, as reflected by the plasma concentrations of ACTH and cortisol, was investigated in 14 children receiving two different premedications during halothane anaesthesia for adenoidectomy. Seven children (group A) were premedicated with diazepam 5 mg rectally and atropine 0.3-0.4 mg sublingually and seven (group B) received a rectal combination of diazepam 0.5 mg kg-1, morphine 0.15 mg kg-1 and hyoscine 0.01 mg kg-1. Before and after surgery plasma concentrations of ACTH and cortisol were lower in group B than in group A. In group A mean values for ACTH increased from 40.7 ng line-1 before adenoidectomy to 352.9 ng litre-1 (P less than 0.001) after adenoidectomy. The corresponding increase in group B was from 12.1 ng litre-1 to 82.1 ng litre-1 (P less than 0.01). In group A mean cortisol concentrations increased from 235.7 nmol litre-1 to 655.7 nmol litre-1 after adenoidectomy (P less than 0.01) and in group B from 121.4 nmol litre-1 to 427.9 nmol litre-1 (P less than 0.01). End-tidal carbon dioxide tension was approximately the same in both groups. It was concluded that the combination of diazepam, morphine and hyoscine decreased the endocrine response to stress.