The effect of Etomidate on corticotropin stimulation test to diagnose relative adrenal insufficiency in septic shock

Introduction

Patients with septic shock were recently found to have relative adrenal insufficiency. Etomidate is known to inhibit 11-beta hydroxylase, which could interfere with the cortisol response to corticotropin.

Hypothesis

Patients who receive Etomidate before the corticotropin stimulation test will have higher incidence of relative adrenal insufficiency.

Methods

In this retrospective study, the electronic records of the 1207 patients who had serum cortisol levels drawn between March 2002 and August 2003 were reviewed and 163 patients who had a short corticotropin stimulation test done during an ICU admission because of septic shock were identified. Our cohort was divided into those who received Etomidate or not before the corticotropin stimulation test. The incidence of relative adrenal insufficiency was compared between these two groups. Data collected included demographics, presence of relative adrenal insufficiency, presence of coagulopathy, the use of steroids or any medication known to interfere with cortisol synthesis, use of Etomidate and the time interval between the administration and the cosyntropin test, history of adrenal/pituitary disease, and mortality. Relative adrenal insufficiency was defined as a response of 9 μg/dl or less after corticotropin stimulation. Septic shock was defined by the ACCP/SCCM criteria. Comparisons between groups were made using the chi-square test.

Results

The patient mean age was 64.6 years; 97% were white, and 58% were male. Coagulopathy was found in 66% of the patients. Ten patients were on dexamethasone before the test. None of the patients were on any medication known to interfere with the test. There was no patient with previous history of adrenal/pituitary disease. Of the 46 patients who received Etomidate, 36 (78%) were diagnosed as having relative adrenal insufficiency compared with 58/117 (50%) patients who did not (P = 0.0008). Relative adrenal insufficiency was noted in 79% of the patients who received Etomidate within 6 hours compared with 78% of the patients who received Etomidate later than 6 hours of the test (P = 0.9246). The mortality rate was 53% (50/94) in patients with relative adrenal insufficiency compared with 61% (42/69) in patients without relative adrenal insufficiency (P = 0.3287).

Conclusion

There is an increased incidence of relative adrenal insufficiency after Etomidate administration in septic shock following Etomidate administration. This increased incidence is unrelated to the time interval between Etomidate administration and the corticotropin test.