Abstract: Objective To study the effects of the priming principle of cisatracurium and increasing the dose on the onset time and the clinical duration. Methods 90 patients ASAⅠ-Ⅱ, aged 18-55 years, scheduled for elective gynecologic surgery were randomly allocated to three groups with 30 cases each. GroupⅠ received cisatracurium 0.15 mg/kg (3ED95). Group Ⅱ received cisatracurium 0.015 mg/kg four minutes before induction and then cisatracurium 0.135 mg/kg. Group Ⅲ received cisatracurium 0.2 mg/kg(4ED95). Neuromuscular block was monitored by a TOF Watch SX accelerograph. The onset time and the clinical duration were recorded.Results The onset times for groupⅠ , Ⅱ and Ⅲ were (184±56) s、 (141±31) s、 (135±45) s seconds respectively. Compared with group I , there was significant difference in group Ⅱ, Ⅲrespectively (P<0.05); the clinical effective time were (41±8) min, (44±6) min, (53±8) min respectively. Compared with that of group Ⅲ, there was a remarkable difference in groupⅠand group Ⅱ(P<0.05). Conclusion The priming principle can significantly shorten cisatracurium onset time of intubation. Compared with increasing the dose, its clinical duration is shorter.

Key words: cisatracurium, priming principle, onset time, clinical duration