Comparison of Pain on Injection of Etomidate versus Etomidate-Lipuro in Patients Undergoing Elective Orthopedic Surgery: A Double-Blind Randomized Clinical Trial

Background: Etomidate is an efficient general anesthetic associated with injection pain. Etomidate-Lipuro is its lipid emulsion, suggested to have less adverse effects. We aim to compare the injection pain of etomidate vs. etomidate-lipuro.   Methods: This double-blind randomized clinical trial investigated 46 hands (23 patients) undergoing elective orthopedic surgery referring to our hospital from May to September 2017. For each patient, intravenous (IV) access was put on both hands, on one of which 2 ml of etomidate (drug A) and on the other one, 2 ml of etomidate-lipuro (drug B) were infused simultaneously. Pain scores were compared between drug types by the Wilcoxon signed-rank test using the SPSS software.   Results: Among 23 patients included in the study, 8 (34.8%) were female. Mean ± standard deviation (SD) of the patients’ age was   40.52 ± 13.07 years (range: 22-60 years). The type of drug injected to the right hand was drug A in 14 hands (60.9%) and drug B in 9 hands (39.1%). Mean ± SD of pain scores was 3.57 ± 3.30 for drug A (P < 0.001). The hand side (left/right) showed no significant effect on the pain scores (P = 0.535).   Conclusion: This randomized clinical trial used each person as his/her own control (left/right hands). Given the results, etomidate-lipuro showed significant superiority over etomidate regarding injection pain. In fact, most patients felt no pain, which suggests etomidate-Lipuro as an appropriate sedative.