研究单位：[1]China International Neuroscience Institution[2]Xuanwu Hospital,Beijing, Beijing, China, 100053
研究目的：
1.The muscle relaxants can improve the conditions of laryngeal mask incubation and reduce the related complications (such as laryngeal spasm and postoperative throat pain)
2.The dosages of muscle relaxants used in various researches vary greatly.
3.We are planning use the most classical method for determining the ED50 or half effective concentration of cis-atracurium using sequential method, which is also called " up and down method" and " ladder method".
