tokens: Depending on the drugs that would be given before the induction of anesthesia with etomidate , the patients were separated into 4 groups : no pretreatment ( Group NP ) , fentanyl 1 ug . kg - 1 ( Group F ) , midazolam 0 . 03 mg . kg - 1 ( Group M ) , and midazolam 0 . 015 mg . kg - 1 + fentanyl 0 . 5 ug . kg - 1 ( Group FM ) .