Tramadol Pretreatment Reduce Myoclonus Induced By Etomidate

Objective:Etomidate is a short-acting non barbiturate sedative hypnotic anesthetic.It is commonly used in clinical anesthesia because of its fast metabolism and little influence on respiratory and circulatory system,etomidate often induces myoclonus during induction of general anesthesia.Myoclonus is a kind of abnormal neuromuscular activity,which can cause damage of muscle fiber,potassium,increase the risk of full gastric reflux in patients with aspiration,elevated intraocular pressure resulting in eye vitreous prolapse.Studies have shown that intravenous preinjection of general anesthesia drugs such as opioids,benzodiazepine and rocuronium can reduce the myoclonus induced by etomidate in varying degrees.Tramadol is a weak agonist of opioid receptors,selectively excitates the receptor,and inhibits the reuptake of five serotonin(5-HT)and norepinephrine(NE).The drug has the characteristics of strong aNElgesic effect,long duration and low dependence potential.It is reported that tramadol has a good effect on the treatment or prevention of shivering and trembling.The treatment dose of tramadol did not inhibit respiration and had no effect on respiratory frequency,tidal volume,and CO2 partial pressure in arterial blood.Because of tramadol better resistance to chills effect and less side effects than other drags,so this study by preinjection low dose(1 mg/kg)and high dose(2 mg/kg)of tramadol observe its influence on myoclonus,to investigate the effect of pretreatment with tramadol on the occurrence of etomidate-induced myoclonus during induction of general anesthesia.Methods:90 adult ASA physical status I-II patients of the Renmin Hospital of Wuhan University scheduled for elective surgery were included in the study during October 2016-February 2017.Patients were allocated to one of three groups in randomized,double-blinded fashion via random number draws to receive either a low dose of tramadol(1 mg/kg;n = 30;Group T1),tramadol(2 mg/kg;n = 30;GroupT2)or placebo(saline;n =30;Group TO).Five minutes after injection,anesthesia was induced with lipid formulation of etomidate(Etomidate-Lipuro)0.3 mg/kg over 30 s intravenously.After 1 min interval,0.6 mg/kg rocuronium was injected into the three groups,and 5 mu g/kg fentanyl was used for tracheal intubation and non invasive arterial blood pressure(BP)and heart rate(HR)were recorded simultaneously.Results:There were no significant differences among the groups with respect to age,height,weight,gender,ASA status or concurrent diseases.Frequency and severity of myoclonic movements were significantly lower in Groups T1 and T2 than in GroupTO(P<0.01).The incidence of side effects(vertigo,NEusea and vomiting)in group T2 was significantly higher than group T1 and group TO(P<0.05).Conclusion:Pretreatment with low dose of tramadol(1 mg/kg)is a good choice for preventing myoclonic movements during etomidate induction.