Objective: To evaluate the effectiveness and safety evaluation of remifentanil hydrochloride.Methods: A total of 120 cases who need operation treatment,were selected and were randomly divided into A and B groups.Patients in Group A were treated by fentanyl combined with nitrous oxide for anesthesia;while patients in Group B were treated by combination of nitrous oxide and remifentanil.The effectiveness and safety were evaluated.Results: In Group B patients felt significantly less pain than that of Group A(P...