Effect Of Dexmedetomidine Intranasal Pretreatment On Etomidate-induced Myoclonus

Objective:This paper is a research to observe the effects of different doses of dexmedetomidine intranasal pretreatment on etomidate inducing myoclonus and whether it would affect the stability of respiration and hemodynamics.Whether there is a significant difference in the degree of prevention of myoclonus at different doses or not.Methods:100 Patients with ASA from grade I to II were selected,who are aged 18⁶0 years old,and all the patients were short operated under general anesthesia（the time of surgery was limited within 2 hours）.The 100 patients were divided into 4 groups with the method of random digital table,including the group of dexmedetomidine（including group D₁,group D₂,group D₃）and the control group（group C）,25 cases in each group.In group D₁,group D₂ and group D₃,the dose of intranasal for dexmedetomidine pretreated by25-30min before anesthesia induction were 0.5ug/kg,1.0ug/kg and 1.5ug/kg respectively.In group C,an equivalent dose of normal saline intranasal was given to 25-30min before anesthesia induction.All four groups were injected with etomidate intravenously within 1minute.Recorded these data of MAP,HR,SpO₂,RR respectively before the pretreatment（T₀）,immediately 10min（T₁）,20min（T₂）after pretreatment and etomidated before administration（T₃）in chronological order.Observed and recorded the occurrence of etomidate myoclonus within 3 minutes after etomidated administration,and assessed the myoclonus degree.Then collected and collated the data,analysised the interrelation between them.Results:The mean arterial pressure and heart rate in group D₂ and group D₃ were significantly lower than that in group C（P<0.05）at T₃ time.The mean arterial pressure,heart rate of group D₂ at time T₃[（88.8±6.8）mmHg,（64.5±7.9）times/min]were lower than those[（94.3±6.6）mm Hg and（93.5±6.5）mmHg,（71.1±8.1）times/min and（70.6±8.0）times/min]at T₀,T₁.The difference is statistically significant（P<0.05）.While the mean arterial pressure,heart rate of group D₃ at time T₂ and T₃[（89.1±6.0）mm Hg and（87.1±6.2）mmHg,（64.8±7.9）times/min and（63.7±7.8）times/min]were lower than those[（94.4±6.7）mm Hg and（93.7±6.5）mmHg,（71.1±8.1）times/min and（70.6±8.0）times/min]at T₀,T₁.The difference is also statistically significant（P<0.05）.There was no statistically significant difference of comparison in or between the groups at any other time points（P>0.05）.The incidence of myoclonus in test group（group D₁:20%,group D₂:12%,group D₃:4%）was significantly lower than that in the control group（group C:72%）.Accordingly,the difference was statistically significant（P<0.01）.Conclusion:Dexmedetomidine intranasal on the adults can effectively prevent etomidate myoclonus during induction of general anesthesia.But with intranasal dose increaseing,the effect would not obvious enhanced.Moreover,it is likely to cause a decrease in mean arterial pressure and heart rate.Therefore,the dose of nose drops recommended in this paper is 0.5ug/kg.