Intraoperative Appliance of Dexmedetomidine During Laparoscopic Resection of Colorectal Cancer:Influence on Early Postoperative Intestinal Function and Long-term Prognosis

Interventions: Dexmedetomidine:Dexmedetomidine 1ug/kg iv.pump;Control:Same dose of NS iv.pump Primary outcome(s): Anus exhaust time;Defecating time;Time of intake;Length of hospitalization;Quality of sleep;Diamine oxidase, DAO;Intestinal fatty acid binding protein, L-FABP Study Design: Parallel