Tehran University of Medical Sciences Archives of Anesthesiology and Critical Care 2423-5849 6 4 2020 11 22 182 187 Alireza Pournajafian Department of Anesthesiology, Firoozgar Hospital, Iran University of Medical Sciences, Tehran, Iran. Ali Khatibi Department of Anesthesiology, Firoozgar Hospital, Iran University of Medical Sciences, Tehran, Iran. Mohammad Reza Ghodraty Department of Anesthesiology, Firoozgar Hospital, Iran University of Medical Sciences, Tehran, Iran. Azadeh Emami Department of Anesthesiology, Ali Asghar Hospital, Iran University of Medical Sciences, Tehran, Iran. Mona Haji Aghajani School of Medicine, Iran University of Medical Sciences, Tehran, Iran. 2020 09 14 2020 10 21 Background: Postoperative cognitive dysfunction (POCD) is amongst the most critical complications after surgery. This study shows the effect of dexmedetomidine on the prevalence of postoperative cognitive impairment. Methods: In this double-blinded clinical trial study, patients aged 60-80 years undergoing pelvic and femoral orthopedic surgery were randomly assigned in one of the two groups of the course, i.e., Dexmedetomidine (DEX) or normal saline (NS). We infuse One hour before anesthesia, one µg/kg dexmedetomidine in the group (DEX), and the same volume of normal saline (NS). Mini-Mental State Examination test (MMSE) was applied to evaluate the patients' cognitive condition, One day before the surgery, 24 and 72 hours after the surgery. Results: There was no significant difference between the two groups in terms of age, sex, duration of anesthesia, duration of surgery, and the amount of bleeding during operation (P>0.0). The postoperative hematocrit level was lower than the preoperative level in the group (DEX) (P<0.05). There was no significant difference in MMSE test scores pre and postoperatively between the two groups (P>0.05). Conclusion: Dexmedetomidine infused before surgery has no preventive effect on POCD in elderly patients undergoing pelvic and femoral orthopedic surgery under general anesthesia. https://aacc.tums.ac.ir/index.php/aacc/article/view/305 https://aacc.tums.ac.ir/index.php/aacc/article/download/305/476