Effects of adding low-dose ketamine to etomidate on serum cortisol levels in critically ill cardiac patients: a randomized clinical trial

Background: Etomidate was associated with an inhibition of adrenal steroid synthesis. This study aimed to evaluate the effects of adding low-dose ketamine to etomidate to minimize the decrease in serum cortisol level in critically ill cardiac patients. Methods: Sixty adult cardiac patients, ≥ 18 years, who underwent upper endoscopy and Colonoscopy to manage acute anemia in the cardiac intensive care units were enrolled. Patients were randomly divided into two groups: (group (E): n = 30) received etomidate 0.2 mg/kg IV followed by etomidate 0.05 mg/kg IV, and (group (KE): n = 30) received ketamine 0.5 mg/kg IV, then etomidate 0.1 mg/kg IV, followed by etomidate 0.05 mg/kg IV. The primary outcome was Serum cortisol level at 6 h after the procedure. Results: The mean postoperative cortisol level was significantly lower in group E (295.60 ± 49.218 nmol/L) versus group KE (461.00 ± 67.946 nmol/L), with 95% CI = 351.94 to 404.66; p = 0.000. In addition, the estimated serum cortisol reduction level was also significant between groups; In group E, the estimated cortisol level decreased nearly 53% from 632.40 ± 35.066 nmol/L to 295.60 ± 49.218 nmol/L 6 hours postoperative. While in group KE, the estimated cortisol level decreased only 27% from 639.13 ± 43.035 nmol/L to 461.00 ± 67.946 nmol/L. Conclusions: Single-dose ketamine (0.5 mg/kg) was helpful to decrease the total dose of etomidate and hence decreased the percentage of serum cortisol level in such critically ill patients with preservation of patient satisfaction. Trial Registration: This study is registered on ClinicalTrials.gov (NCT04857450; principal investigator: Mostafa Mohammed Elsaid Elhamamsy; registration date: 23/04/ 2021).