小儿心脏手术前一般都用较大剂量的术前药来减轻焦虑反应并便于诱导,常规注镇静镇痛药虽然有效,但常引起循环呼吸抑制。作者发现这类患儿术前口服氯胺酮比较安全而有效。作者选择40例先天性心脏病儿童,随机分为A、B两组。两组患儿都在术前2小时先口服异丁嗪(trimeprazine)3mg/kg。术前1小时A组患儿肌注吗啡0.1mg/kg;B组口服 Preoperative pediatric cardiac surgery generally use a larger dose of preoperative medicine to reduce anxiety and ease of induction, routine injection of sedative analgesics, although effective, often cause respiratory depression. The authors found that these children preoperative oral ketamine more safe and effective. The author chose 40 cases of congenital heart disease children, were randomly divided into A, B two groups. Both groups received oral trimeprazine 3 mg / kg 2 hours prior to surgery. One hour before operation, group A was intramuscularly injected morphine 0.1 mg / kg; group B was orally administered