Objective. To investigate the association between exposure to general anesthesia and the development of Alzheimer’s disease (AD) and dementia by reviewing and integrating the evidence from epidemiological studies published to date. Methods. We searched MEDLINE, EMBASE, and Google Scholar to identify all relevant articles up to April 2018 reporting the risk of AD/dementia following exposure to general anesthesia and finally updated in February 2020. We included patients older than 60 or 65 years who had not been diagnosed with dementia or AD before the study period. The overall pooled effect size (ES) was evaluated with a random‐effect model. Subgroup analyses were conducted and possibility of publication bias was assessed. Results. A total of 23 studies with 412253 patients were included in our analysis. A statistically significant positive association between exposure to general anesthesia and the occurrence of AD was detected in the overall analysis (pooled ES = 1.11, 95%confidence interval = 1.07–1.15), but with substantial heterogeneity (, I² = 79.4). Although the overall analysis revealed a significant association, the results of the subgroup analyses were inconsistent, and the possibility of publication bias was detected. Conclusions. This meta‐analysis demonstrated a significant positive association between general anesthesia and AD. However, considering other results, our meta‐analysis must be interpreted with caution. Particularly, it should be considered that it was nearly impossible to discriminate the influence of general anesthesia from the effect of surgery itself on the development of AD. Further, large‐scale studies devised to reduce the risk of bias are needed to elucidate the evidence of association between general anesthesia and AD. Trial registration. PROSPERO International prospective register of systematic reviews CRD42017073790.

The present study aimed to compare the intravenous bolus effect of oxycodone and fentanyl on hemodynamic response after endotracheal intubation and postoperative pain in patients undergoing closed reduction of nasal bone fracture. In this prospective randomized double-blinded study, 64 patients undergoing closed reduction of nasal bone fracture were randomized into one of two groups: the fentanyl group (Group F) or the oxycodone group (Group O). Each drug (fentanyl 2 mcg/kg in Group F and oxycodone 0.2 mg/kg in Group O) was administered prior to the induction of general anesthesia. Hemodynamic changes after endotracheal intubation and postoperative pain were then measured in both groups. There was no significant difference in the change in mean arterial pressure and heart rate between pre-induction and post-intubation in both Groups F and O (P > 0.05). Postoperative pain in Group O was milder than that in Group F (P < 0.001); however, time to awakening from the end of operation was shorter in Group F (P = 0.012). In patients undergoing closed reduction of nasal bone fracture, oxycodone attenuates hemodynamic response to endotracheal intubation similar to fentanyl. However, oxycodone is more effective than fentanyl in improving postoperative pain. Clinical Research Information Service (Trial registry number: KCT0001153 ) on 3 July, 2014

Dexmedetomidine can be used for the prevention of emergence agitation (EA) in children. However, an inadequate dose of dexmedetomidine can induce prolonged sedation and cardiovascular complications. The aim of this study was to evaluate the effective dose of dexmedetomidine for the prevention of EA after desflurane anesthesia for patients undergoing a tonsillectomy or adenoidectomy. We enrolled 21 unpremedicated children, between 2 and 12 years, undergoing either a tonsillectomy or an adenoidectomy. General anesthesia was induced using sevoflurane and oxygen, and dexmedetomidine was administered before surgery. Anesthesia was maintained using desflurane resulting in a BIS range of 40–60. In the postanesthetic care unit (PACU), EA (agitation measured at level 4 or more at least once) was assessed on arrival in the PACU,15 min later, and 30 min later. The dose of dexmedetomidine for consecutive patients was determined by the response of the previous patient, using an increment or decrement of 0.1 μg/kg. The 50 % effective dose of dexmedetomidine for prevention of EA was 0.25 μg/kg (95 % confidence limits, 0.17–0.33 μg/kg), and the 95 % effective dose was 0.38 μg/kg (95 % confidence limits, 0.29–0.39 μg/kg). For prevention of EA after desflurane anesthesia for 50 % and 95 % of children undergoing tonsillectomies or adenoidectomies, 0.25 μg/kg or 0.38 μg/kg of dexmedetomidine is suggested. Further study is needed to validate the suggested dose of dexmedetomidine to prevent the EA that was identified in the present study. Clinical Research Information Service KCT0000126 .

Park YH, et al. J Korean Med Assoc. 2015 Nov;58(11):1011-1018. http://dx.doi.org/10.5124/jkma.2015.58.11.1011