The effect of melatonin on early postoperative cognitive decline in elderly patients undergoing hip arthroplasty: A randomized controlled trial

The purpose of the present study was to investigate whether exogenous melatonin supplementation could ameliorate early postoperative cognitive decline (POCD) in aged patients undergoing hip arthroplasty with spinal anesthesia. Prospective cohort study. Department of Anesthesiology, Jinling Hospital, Nanjing University, Nanjing, China. One hundred and thirty–nine patients with ASA I–III, older than 65 yr of age (mean age: 74.5 ± 5.5; gender: male 53 and female 86), scheduled for hip arthroplasty were included in the present study. Patients were randomized to receive 1 mg oral melatonin or placebo daily 1 h before bedtime one day before surgery and for another 5 consecutive days postoperatively. The subject assessment, including Mini–Mental State Examination (MMSE) score, subjective sleep quality, general well–being, postoperative fatigue, and visual analogue scale for pain were evaluated pre–operatively and at days 1, 3, 5, and 7 after surgery. The MMSE score in the control group decreased significantly after surgery when compared with its own preoperative value or the melatonin group at days 1, 3, and 5. However, the MMSE score in the melatonin group remained unchanged during the 7 days of monitoring. In addition, significant postoperative impairments of subjective sleep quality, general well–being, and fatigue were found in the control group when compared with the melatonin group. Peroperative melatonin supplementation might improve early POCD, suggesting restoration of normal circadian function with good sleep quality may be one of the key factors in preventing or treating POCD.