Effect of Vitamin C on Serum Cortisol after Etomidate Induction of Anesthesia

Objectives: Etomidate is suitable for induction of anesthesia, especially in elderly patients and patients who have cardiovascular compromise. Vitamin C has been introduced as a treatment option to decrease Etomidate induced adrenal insufficiency but its actual effect is still controversial. Objective is to determine the effect of Vitamin C on reduction of serum cortisol after etomidate induction of anesthesia. Methods: In a randomized clinical trial, 40 patients of ASA class I & II, aged between 25 to 70 years old, candidate for elective laparatomy were selected. One hour before induction of surgery, 1 gram of intravenous Vitamin C were administered to the patients in Vitamin C group. Two blood samples were obtained 5 minutes before induction and then another sample 4 hours after induction with etomidate after surgery. All samples were measured for serum free cortisol, ACTH, and C-reactive protein (CRP). Results: There were no significant differences between duration of surgery, preoperative and post-operative blood pressure and heart rate in two groups (p>0.05). Serum cortisol was significantly declined in control group from 16.2?6.3 ?g/dl in preoperative to 8.5?4.2 in postop (p=0.0005), but not in Vitamin C group from 17.5?5.6 in preop to 16.8?6.4 in postop (p=0.75). ACTH levels increased non-significantly from preop to postop period in both Vitamin C (pre: 52.1?15 vs. post: 56.4?18 pg/ml) (p=0.48) and in control group (pre:50.5?16 vs. post:56.2?20). Conclusion: Etomidate could significantly decrease postoperative serum free cortisol and induce adrenocortical suppression and CRP increase. This effect could be reversed by using Vitamin C premedication to maintain serum cortisol at preoperative level.