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The effect of remifentanil for reducing myoclonus during induction of anesthesia with etomidate
Sang Woo Lee1, Hyun Jue Gill1, Sung Chul Park1
1Department of Anesthesiology and Pain medicine, School of Medicine, CHA University, Seongnam, Korea. gill5432@naver.com.
Background:
Myoclonic movement is a common problem during induction of anesthesia with etomidate. We investigated the influences of pretreatment with remifentanil on etomidate induced myoclonus.
Methods:
Ninety ASA class I patients were divided randomly into three groups. Group NS received normal saline 2 ml as placebo (n = 30), group R0.5 and group R1.0 were pretreated with remifentanil 0.5 microgram/kg (n = 30) or 1.0 microgram/kg (n = 30) 1 minute before induction with etomidate 0.3 mg/kg. Orotracheal intubation was performed after administration of rocuronium 0.5 mg/kg. We assessed the incidence, onset, duration and intensity of myoclonus. Mean arterial pressure (MAP), heart rate (HR) and bispectral index (BIS) were recorded during induction.
Results:
Twenty five patients developed myoclonus in group NS (83.3%), 3 patients in group R0.5 developed myoclonus (10%), as did 5 patients in group R1.0 (16.7%). Moderate to severe myoclonus of grade 3 and 4 were found 66.7% of patients in group NS, whereas no patients in both remifentanil pretreated groups developed this grade of myoclonus. The duration of myoclonus was reduced significantly in the remifentanil groups: 93.8 +/- 59.5 sec in group NS, 49.3 +/- 34.9 sec in group R0.5, 36.0 +/- 27.0 sec in group R1.0 (P < 0.05). HR was decreased by pretreatment with remifentanil prior to induction, while MAP and HR were decreased after induction with etomidate (P < 0.05). BIS changes were not different among the three groups. The dose dependent differences between the two remifentanil doses were not noticed.
Conclusions:
Pretreatment with remifentanil significantly reduced the incidence, duration and intensity of etomidate induced myoclonus.
Insights
Pretreatment with remifentanil significantly reduces etomidate-induced myoclonus, decreasing its incidence, duration, and intensity. This anesthesia adjunct offers a safer induction process by mitigating involuntary muscle movements.
Area of Science:
- Anesthesiology
- Pharmacology
Background:
- Myoclonic movements are a frequent complication during anesthesia induction using etomidate.
- Investigating methods to mitigate these side effects is crucial for patient safety.
Purpose of the Study:
- To evaluate the efficacy of remifentanil as a pretreatment agent for reducing etomidate-induced myoclonus.
- To assess the impact of different remifentanil dosages on myoclonus characteristics.
Main Methods:
- A randomized study involving 90 patients pretreated with normal saline (placebo), remifentanil 0.5 mcg/kg, or remifentanil 1.0 mcg/kg before etomidate induction.
- Incidence, onset, duration, and intensity of myoclonus were recorded, alongside hemodynamic parameters (MAP, HR) and Bispectral Index (BIS).
Main Results:
- Remifentanil pretreatment significantly decreased the incidence of myoclonus (10% for 0.5 mcg/kg, 16.7% for 1.0 mcg/kg) compared to placebo (83.3%).
- Moderate to severe myoclonus was eliminated in remifentanil groups. Myoclonus duration was substantially reduced (e.g., 36.0 sec with 1.0 mcg/kg remifentanil vs. 93.8 sec for placebo).
- Remifentanil decreased heart rate pre-induction; etomidate decreased MAP and HR post-induction. No significant differences in BIS were observed. Dose-dependent effects of remifentanil were not evident.
Conclusions:
- Remifentanil pretreatment is effective in reducing the incidence, duration, and intensity of myoclonus associated with etomidate anesthesia.
- Remifentanil offers a valuable strategy for improving the safety and tolerability of etomidate induction.
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