Effects of edaravone on postoperative cognitive function in elderly patients undergoing hip joint replacement surgery: A randomized controlled trial

Background: Postoperative cognitive dysfunction (POCD) is a complication of central nervous system in patients after surgery. Edaravone as a brain-protective agent may have protective effect on postoperative cognitive function. The study was designed to explore the effects of edaravone on postoperative cognitive function in elderly patients undergoing hip joint replacement surgery and potential mechanism. Patients and methods: Patients undergoing hip joint replacement surgery were randomly allocated into 2 groups: the edaravone group (group E) and the control group (group C). Group E received intravenous edaravone at a dose of 0.5 mg/kg after induction of anesthesia, while group C received normal saline. The cognitive function was evaluated with the Mini-Mental State Examination (MMSE) 1day before surgery,3 days and the 7 days after surgery. Patients' plasma samples were collected to detect the levels of S100 beta protein (S100 beta), interleukin-6 (IL-6), matrix metalloproteinase-9 (MMP-9), superoxide dismutase (SOD) and malondialdehyde (MDA) before the induction of anesthesia, at the end of surgery and on postoperative day 3. Results: The MMSE scores in group E were higher than those of group C 3 days after surgery (25.98 +/- 1.99 vs 24.86 +/- 1.86, p = 0.003). There were remarkable rises (p < 0.05) in plasma IL-6, S100 beta and MMP-9 levels at the end of surgery and on postoperative day 3 in the two groups, however, edaravone pretreatment could reduce these levels to a certain extent compared with group C (p < 0.05). In group E, the SOD concentration was higher at the end of surgery (16.03 +/- 2.46U/ml vs. 13.65 +/- 2.53U/ml, p = 0.0001), while the MDA level was lower on postoperative day 3 than those in group C (7.01 +/- 2.37 nmol/ml vs. 11.34 +/- 3.18 nmol/ml, p = 0.0001). Conclusion: The results indicated that preoperative intervention with edaravone may improve the postoperative cognitive function in elderly patients undergoing hip joint replacement surgery.