A commentary on ‘Preventing postoperative cognitive dysfunction using anesthetic drugs in elderly patients undergoing noncardiac surgery: a systematic review and meta-analysis’

Laparoscopic cholecystectomy is performed with increasing frequency in aging populations. However, in elderly patients, cognitive dysfunction following surgery may impair the outcome of surgical procedures. Dexmedetomidine (DEX) has been demonstrated to have a neuroprotectve effect in animal experiments. However, it is unclear whether DEX also has a neuroprotective effect in human patients. The present study was a randomized, placebo-controlled double-blind trial of 126 patients who had undergone laparoscopic cholecystectomy, using clinical interviews to determine whether intravenously administrated DEX during general anesthesia ameliorates cognitive function impairment. The cognitive deficit of each patient was assessed using the Mini-Mental State Examination (MMSE). The scores on the MMSE for the DEX and control groups one week after surgery (DEX group, 27.6±1.2; control group, 25.7±1.5) were significantly different (P=0.005). The MMSE scores of patients ≤65 years old were significantly higher than those of patients >65 one week after surgery. The MMSE scores were significantly different between the two age groups in the control patients (≤65 years old, 28.3±1.2; >65 years old, 26.6±2.1; P=0.036), while the difference was not statistically significant in the DEX-treated patients. Eight patients in the DEX group and 15 patients in the control group had mild cognitive impairment (26≥ MMSE score ≥21) although the difference was not statistically significant. The findings of the present study support the hypothesis that DEX administration may be an effective method for ameliorating postoperative cognitive impairment in elderly patients who have undergone laparoscopic cholecystectomy. Further research is required to confirm the findings of the present study.

Background: This study aimed to compare the effects of preoperative administration of midazolam and dexmedetomidine on cognitive dysfunction prevention after cataract surgery. Materials and Methods: This research was a double-blind controlled clinical trial. In this study, 150 candidates for cataract surgery under general anesthesia, over 65 years, and similar to American Society of Anesthesiologists I and II characteristics were selected as the sample and randomly assigned to three groups. Participants of these three groups were treated with 0.1 mg/kg of midazolam, 1 μg/kg of dexmedetomidine, and the same volume of normal saline (control), respectively. Hemodynamic parameters and cognitive dysfunction score of the participants were measured using the Mini-Mental State Examination (MMSE) before the surgery, 24 h and 1 week after the surgery. Results: An evaluation of hemodynamic parameters before anesthesia up to 24 h after the surgery showed no significant difference between the midazolam, dexmedetomidine, and control groups in terms of systolic and diastolic blood pressure, heart rate, and blood oxygen saturation (P > 0.05). In addition, there was no statistically significant difference between the midazolam and dexmedetomidine groups in the MMSE score before the surgery and 24 h and 1 week after that (P > 0.05). However, there was a significant difference between these two groups and control (P < 0.05). Conclusion: There was no significant difference between midazolam and dexmedetomidine in reducing postoperative cognitive dysfunction (POCD). However, there is a significant difference between these two groups and control. Hence, either midazolam or dexmedetomidine can be prescribed to reduce POCD in cataract surgeries.