Modification of corticosteroid synthesis by etomidate/fentanyl and air anesthesia

The characteristics of cortisol synthesis blockade by an etomidate/fentanyl combination was explored in a group of seven patients undergoing major abdominal vascular surgery. Cortisol, androstene-dione 11-deoxy cortisol (compound S) and ACTH were measured during surgery for three hours. In the fourth hour an ACTH1-24 stimulation test was performed and the reaction of the corticosteroid synthesis was assessed. ACTH and androstene-dione showed a stable concentration during the study, the reaction of androstene-dione to ACTH1-24 was blunted but normal. Compound S and cortisol concentrations decreased during anesthesia and showed no significant increase after stimulation with ACTH1-24. These results indicate that the infusion of etomidate and fentanyl may cause a blockade of the corticosteroid synthesis. The blockade is situated at the place where the conversion of cholesterol to pregnenolone occurs. Because the study was done in clinical setting the results should be interpreted carefully, and confirmed by experimental laboratory results.