A novel approach to the prevention of postoperative delirium in the elderly after gastrointestinal surgery.

PURPOSE: Postoperative delirium (POD) is known to be one of the most critical complications of major operative procedures in elderly patients. Since disorders of the sleep-wake cycle have been reported to be one of the key factors in POD, we attempted to clarify the effectiveness of improving sleep-wake cycle disorders with medication after surgery to prevent POD, by conducting a prospective randomized study of 42 elderly patients who underwent resection of either gastric or colon cancer through an open laparotomy.

METHODS: The delirium-free protocol (DFP) group was given an intramuscular injection of diazepam at 20:00 h each night, as well as a continuous intravenous infusion of flunitrazepam and pethidine administered over 8 h, for the first three nights postoperatively. Two patients were excluded because of failure to complete the DFP.

RESULTS: The incidence of POD was 7/20 (35.0%) in the non-DFP group and 1/20 (5.0%) in the DFP group, this difference being significant (P = 0.023). Morning lethargy produced by the DFP was observed in 40% of the DFP group; however, no other side effects were seen.

CONCLUSIONS: These findings indicate that DFP treatment is effective for controlling POD in elderly patients after general surgery and does not appear to be associated with severe complications or side effects. To our knowledge, this is the first report proposing artificial control of the sleep-awake rhythm by medication as a means of preventing POD in elderly patients.