Backgroud & Objective : Inducing of safe airway and rapid , is very important in the anesthesia of emergency patients and it reduces many complications because of delay in the endotrachal intubation .In this group of patients, administration of succinylcholin is a choice. But, this drug has serious complication, that is sudden increase of serum potassium level , and could cause cardiac arrest .So ,it is suggested, use of non blocker dose of non depolarizant neuromuscular blocker (defasciculation), for reducing this response . So , the aim of this study , was to determine the effect of pretreatment atracurium on serum potassium level associated with administration of succinylcholine .

  Methods: This study was performed clinical trial on 82 elective patients aged between 15 -70 years whit ASAI-II (American society of anesthesiology of physical status class)who where scheduled undergo operate general surgery. Premedication drugs are used to all patients , according to weight. and first blood sample was taken, considered as control group. then pretreatment atracurium injection (50mcg/kg) and after three minutes, was performed induction with thiopental sodium (5mg/kg) and succinylcholine (1.5 mg/kg ), and after 5 minutes , second blood sample was taken, test group . blood samples, were poured in the espicial tube of serum potassium and immediately , serums were separated . Then , potasiom level of serums were measured with micro light . The datas analyzed with statistical program ( spss) and then , were compared .

  Results: According to the obtained results , the mean of serum potassium level after administration of succinylcholine associated with defasciculation atracurium and before the administration of pretreatment atracurium (base level) was not different . It was not seen , a statistically significant difference between two groups, with attention to paired- t-test(p=0.936) and wilcoxon signed ranks test (p=0.594).

  Conclusion: Regarding the results of this study , administration of pretreatment atracurium is not effective in prevention of hyperkalemia induced by succinylcholin with attention base level.