[Regulation of the response of the hypothalamo-hypophyseal-adrenal axis during anesthesia with diazepam-fentanyl in heart surgery].

OBJECTIVES

To study the response of the hypothalamic-hypophysial-adrenal axis during heart surgery under anesthesia with diazepam-fentanyl (D-F) at high doses.

MATERIAL AND METHODS

We studied the intraoperative response of cortisol, ACTH, and 11-deoxycortisol and aldosterone (RIA) to heart surgery under anesthesia with 0.5 mg/kg diazepam and 0.1 mg/kg fentanyl in 12 patients (group D-F) and the effect on that response of blocking peripheral cortisol production with etomidate (0.15 mg/kg bolus) (group D-F-E, n = 12).

RESULTS

Sharp drops in cortisol, ACTH and 11-deoxycortisol levels were observed in group D-F before the start of extracorporeal circulation (ECC). Albumin and red blood cell counts fell less sharply than did hormone levels. ACTH levels increased after ECC. Throughout surgery, ACTH and cortisol never rose over preanesthetic levels. The response in group D-F-E was similar, with a clear early rise in 11-deoxycortisol and a later rise in ACTH.

CONCLUSIONS

Anesthesia with D-F lowers levels in the hypothalamic-hypophysial-adrenal axis below baseline in the phase before ECC, despite the stimulus of surgery and the effect of hemodilution. After ECC, ACTH levels rise. The response seen in group D-F-E suggests that levels in the hypothalamic-hypophysial-adrenal axis are below normal, but that the mechanism is functioning appropriately.