Effect of intraoperative application of ketamine on postoperative depressed mood in patients undergoing elective orthopedic surgery

120 patients scheduled to undergo elective orthopaedic surgery were randomized to receive either 0.5 mg/kg ketamine with 0.25 mg/kg/h of continuous ketamine infusion for 30 minutes, or 0.5 mg/kh 0.9% saline with 0.25 mg/kg/h of continuous saline infusion for 30 minutes. The purpose of this study was to determine the effects of intraoperative ketamine administration on patients' postoperative depressive mood using the Patient Health Questionnaire-9 (PHQ-9). Serum brain-derived neurotrophic factor (BDNF) level, intraoperative blood loss, operative time, postoperative visual analogue scale (VAS) pain scores and perioperative complications were also assessed. Findings indicated significantly improved PHQ-9 scores for depressive moods, as well as increased serum BDNF levels and reduced VAS scores after intraoperative ketamine compared to intraoperative saline.