COMPARATIVE ASSESSMENT OF THE EFFICACY OF TECHNIQUES FOR ADMINISTERING ETOMIDATE IN PREVENTION OF ETOMIDATE INDUCED MYOCLONUS.

Abstract

Background: Etomidate is a preferred induction agent in patients with limited cardiovascular reserve but is frequently associated with etomidate-induced myoclonus (EIM), which can be distressing and potentially hazardous in selected clinical scenarios. Various pharmacological and technique-based strategies have been proposed to attenuate EIM, but the optimal practical approach in routine practice remains unclear.

Methods: In this prospective, randomized, observational study, 60 ASA I–II patients aged 18–60 years scheduled for elective surgery under general anesthesia were allocated into three groups (n=20 each): Control (normal saline pretreatment, etomidate 0.3 mg/kg rapid bolus), Priming + Slow Injection (priming dose etomidate 0.03 mg/kg followed 60 seconds later by 0.27 mg/kg over 30–60 seconds), and Fentanyl Pretreatment (fentanyl 2 μg/kg pretreatment, etomidate 0.3 mg/kg rapid bolus). Incidence and severity of myoclonus (4-point scale) were the primary outcomes; onset, duration of myoclonus, time to loss of consciousness, hemodynamics, pain on injection, and adverse effects were recorded as secondary outcomes.

Results: Baseline demographic and clinical characteristics were comparable across groups. The incidence of EIM was significantly lower in the Priming + Slow Injection (30%) and Fentanyl Pretreatment (40%) groups compared with the Control group (85%, p<0.001). Severe (Grade 3) myoclonus occurred in 25% of control patients but was completely abolished in both intervention groups. Among patients who developed myoclonus, onset was significantly delayed and duration significantly shortened in the Priming + Slow Injection group (52.8±8.3 s and 8.2±2.5 s, respectively) compared with Fentanyl Pretreatment (38.5±6.7 s; 10.8±3.2 s) and Control (24.3±5.2 s; 18.5±4.8 s; p<0.001). Hemodynamic variables remained stable and comparable between groups, pain on injection was minimal, and adverse events were infrequent with no significant inter-group differences.

Conclusion: Both priming with slow injection of etomidate and fentanyl pretreatment effectively reduce the incidence and severity of etomidate-induced myoclonus without compromising hemodynamic stability or increasing adverse effects. The priming with slow injection technique offers superior control of onset and duration of myoclonus and represents a simple, drug-sparing strategy suitable for routine clinical practice.