Abstract: Objective To investigate the effects of propofol infusion by different methods on delirium in the elderly patients receiving hip replacement surgery. Methods Sixty patients undergoing hip replacement with general anesthesia were assigned into dose-loop target control infusion group(group A)and experienced group(group B) by random number table with 30 cases in each group. The events in operation were recorded and compared, including anesthesia time, surgery time, fluid volume, blood loss, urine volume. The total usage of propofol, remifentanil and cisatraeurium, and the incidence rates of emergence agitation, postoperative nausea and vomiting and intraoperative awareness were also recorded and compared. The cognitive function score of patients before and after anesthesia, the incidence rate of postoperative delirium were recorded and compared between the two groups. Results The perioperative dosages of propofol and cisatraeurium in group A were significantly lower than those in group B (P<0. 05). The CAM scores in group A were significantly lower than those in group B 2, 6 hours after operation. The incidence rate of postperative delirium in group A and group B was 17. 2%, 37. 9% respectively (P=0. 078). Conclusions Closed loop target control infusion of propofol can reduce the dosage of anesthetics and the incidence rate of postoperative delirium.

Key words: methods of infusion, target controlled infusion, propofol, aged, delirium