ABSTRACT
Objective To evaluate the effects of dexmedetomidine on the permeability of blood-brain barrier in rats subjected to global cerebral ischemia-reperfusion (I/R).Methods Thirty-six male Sprague-Dawley rats,weighing 250-300 g,were randomly divided into 3 groups (n =12 each):sham operation group (group S),global cerebral I/R group (group I/R) and dexmedetomidine group (group D).Global cerebral I/R was induced by occlusion of bilateral common carotid arteries combined with hypotension (MAP was maintained at 35-45 mm Hg) in anesthetized rats.In group D,dexmedetomidine was infused at a rate of 3μg· kg-1 · h-1 until 2 h of reperfusion after a loading dose of dexmedetomidine 3 μg/kg was injected intravenously immediately after onset of I/R.The rats were sacrificed at 24 h of reperfusion and their brains were immediately removed for microscopic examination of hippocampal CA1 region and for determination of the cell apoptosis,brain water content,Evans blue content and aquaporin 4 (AQP4) expression.Results The number of apoptotic cells was significantly larger,and brain water content,Evans blue content and AQP4 expression were higher in groups I/R and D than in group S (P ＜ 0.05 or 0.01).The number of apoptotic cells was significantly smaller,and brain water content,and Evans blue content and AQP4 expression were lower in group D than in group I/R (P ＜ 0.05 or 0.01).Global cerebral I/R-induced pathological changes were significantly attenuated in group D.Conclusion Dexmedetomidine can decrease the permeability of blood-brain barrier and attenuate global cerebral I/R injury in rats,and down-regulation of AQP4 expression may be involved in the mechanism.
ABSTRACT
Objective To investigate the effect of dexmedetomidine on agitation during recovery from sevoflurane anesthesia in children. Methods Three hundred ASA Ⅰ or Ⅱ children, aged 4-7 yr, weighing 16-30kg, scheduled for elective ear-nose-throat operation under general anesthesia, were randomly divided into 2 groups ( n = 150 each) : control group (group C) and dexmedetomidine group (group D) . Dexmedetomidine 0.5 μg/kg in 20 ml was infused intravenously over 10 min before anesthesia induction in group D, while equal volume of normal Saline was infused in group C. Anesthesia was induced with inhalation of 8 % sevoflurane 5 min after the end of administration . The children were tracheal incubated and mechanically ventilated. Anesthesia was maintained with inhalation of 2 % -3 % sevoflurane. BIS was maintained at 40-60 during operation. The recovery time and agitation within 2 h after operation were recorded. Results There was no significant difference in the recovery time between the two groups ( P > 0.05) . The incidence of agitation was significantly lower in group D than in group C ( P <0.05 ) . Conclusion Dexmedetomidine can reduce the occurrence of agitation during recovery from sevoflurane anesthesia in children.