[Changes in expression of lymphocyte surface markers following administration of etomidate, midazolam or...

Stress alters cellular immunity, affecting lymphocyte function, total lymphocyte count, and the frequency distribution of the lymphocyte subpopulations. Cortisol may mediate these stress-related changes, and drugs affecting cortisol levels might therefore alter lymphocyte patterns. Etomidate and midazolam both prevent the normal perioperative cortisol increase in minor surgery, but the mechanisms by which they do this are not identical: etomidate inhibits steroid synthesis in the adrenal cortex, leading to low cortisol and high ACTH levels, whereas midazolam primarily prevents ACTH increases. Methohexital has little or no influence on cortisol levels. By comparing the effects of these three drugs on the expression of lymphocyte surface markers and the interleukin-2 (Il-2) receptor, we hoped to gain further information on the effects of perioperative cortisol changes on cellular immunity. METHODS. Healthy, young male patients scheduled for routine body surface operations were premedicated with 2 mg flunitrazepam the evening before surgery and 50 mg promethazine and 15 mg piritramide i.m. 1 h before arrival in the operating room. Anaesthesia was induced with 0.2-0.3 mg fentanyl, 2 mg pancuronium, and either etomidate (0.3 mg/kg body wt.), midazolam (0.2 mg/kg body wt.), or methohexital (1.5 mg/kg body wt.). The induction bolus was followed by an infusion at the rate of 0.36 mg/kg/h for etomidate, 0.09 mg/kg/h for midazolam, and no infusion for methohexital. Intubation was facilitated with 100 mg succinylcholine. The patients were ventilated to normocapnia with 66% nitrous oxide in oxygen. Fentanyl was given as 0.1 mg bolus injections whenever necessary.(ABSTRACT TRUNCATED AT 250 WORDS)