Liang He1, Ying Ding1, Huiyu Chen1, Yanning Qian2, Zhong Li3. 1. Department of Anaesthesiology, The Second Affiliated Hospital of Nanjing Medical University, Nanjing, China. 2. Department of Anaesthesiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China. 3. Key Laboratory of Modern Toxicology (Ministry of Education), School of Public Health, Nanjing Medical University, Nanjing, China.
Abstract
QUESTIONS UNDER STUDY: Myoclonic movements are common problems during induction of anaesthesia with etomidate. The myoclonus occurring after etomidate administration may represent a form of seizure. Agonistic modulation of the κ opiate receptor may reduce seizures, and butorphanol acts in such a manner. The aim of this randomised, double-blind, placebo-controlled clinical trial was to test our hypothesis that pre-treatment with butorphanol might reduce the incidence and severity of myoclonus induced by etomidate. METHODS: Patients (108) with American Society of Anaesthesiologists physical status I or II were randomly assigned to one of two groups to receive either 0.015 mg/kg of butorphanol (n = 54) or saline (n = 54) intravenously. At two minutes after infusion of butorphanol or saline, 0.3 mg/kg etomidate was given. The occurrence and severity (observational score of 0-3) of myoclonus was assessed during 2 minutes after administration of etomidate. For each patient, blood pressure (BP), saturation of peripheral oxygen (SpO₂), and heart rate (HR) were measured. RESULTS: The incidence of myoclonus was significantly lower in Group Butorphanol than in Group Saline (13.0% vs 79.6%; RR = 0.163, 95%CI: 0.081-0.329; χ² = 48.265, p <0.0001). The severity levels of myoclonic movement were also significantly lower in Group Butorphanol than in Group Saline (p <0.0001). Throughout the procedure, changes of BP, SpO₂, and HR did not differ between the groups. There were no problems with bradycardia or hypotension. CONCLUSIONS: Infusion of 0.015 mg/kg butorphanol 2 minutes before etomidate administration is effective for suppressing myoclonus induced by etomidate during induction of general anaesthesia.
RCT Entities:
QUESTIONS UNDER STUDY: Myoclonic movements are common problems during induction of anaesthesia with etomidate. The myoclonus occurring after etomidate administration may represent a form of seizure. Agonistic modulation of the κ opiate receptor may reduce seizures, and butorphanol acts in such a manner. The aim of this randomised, double-blind, placebo-controlled clinical trial was to test our hypothesis that pre-treatment with butorphanol might reduce the incidence and severity of myoclonus induced by etomidate. METHODS:Patients (108) with American Society of Anaesthesiologists physical status I or II were randomly assigned to one of two groups to receive either 0.015 mg/kg of butorphanol (n = 54) or saline (n = 54) intravenously. At two minutes after infusion of butorphanol or saline, 0.3 mg/kg etomidate was given. The occurrence and severity (observational score of 0-3) of myoclonus was assessed during 2 minutes after administration of etomidate. For each patient, blood pressure (BP), saturation of peripheral oxygen (SpO₂), and heart rate (HR) were measured. RESULTS: The incidence of myoclonus was significantly lower in Group Butorphanol than in Group Saline (13.0% vs 79.6%; RR = 0.163, 95%CI: 0.081-0.329; χ² = 48.265, p <0.0001). The severity levels of myoclonic movement were also significantly lower in Group Butorphanol than in Group Saline (p <0.0001). Throughout the procedure, changes of BP, SpO₂, and HR did not differ between the groups. There were no problems with bradycardia or hypotension. CONCLUSIONS: Infusion of 0.015 mg/kg butorphanol 2 minutes before etomidate administration is effective for suppressing myoclonus induced by etomidate during induction of general anaesthesia.