Small-dose ketamine improves the postoperative state of depressed patients.

Unlabelled: We investigated whether ketamine is suitable for depressed patients who had undergone orthopedic surgery. We studied 70 patients with major depression and 25 patients as the control (Group C). The depressed patients were divided randomly into two groups; patients in Group A (n = 35) were induced with propofol, fentanyl, and ketamine and patients in Group B (n = 35) were induced with propofol and fentanyl, and all patients were maintained with 1.5%-2.0% isoflurane plus nitrous oxide. The mean Hamilton Depression Rating (HDR) score was 12.7 +/- 5.4 for Group A and 12.3 +/- 6.0 for Group B 2 days before surgery and 9.9 +/- 4.1 for Group A and 14.4 +/- 3.8 for Group B 1 day after surgery. The HDR score in Group A 1 day after surgery was significantly (P < 0.05) lower than that in Group B. The HDR score in Group C was 4.2 +/- 1.7 2 days before surgery and 4.8 +/- 1.6 1 day after surgery. Depressed mood, suicidal tendencies, somatic anxiety, and hypochondriasis significantly decreased in Group A as compared with Group B. Postoperative pain scores in Group A at 8 and 16 h after the end of anesthesia were 26.6 +/- 8.7 and 24.9 +/- 8.2, respectively, which were significantly (P < 0.05) lower than 34.3 +/- 12.0 and 31.1 +/- 8.8 in Group B. In conclusion, small-dose ketamine improved the postoperative depressive state and relieved postoperative pain in depressed patients.

Implications: NMDA receptor antagonists are reported to be effective for improving depression. It remains unclear whether ketamine, which is an NMDA receptor antagonist, postoperatively affects the psychological state in depressed patients. We investigated the effect of 1.0 mg/kg of ketamine on postoperative outcomes in depressed patients.