Neuroprotective effect of α2 adrenergic receptor agonist in infants with cardiopulmonary bypass

Abstract

Objective To determine the effect of α2 adrenergic receptor agonist dexmedetomidine on the expression of nuclear factor (NF) -κB and cerebral injury in infants with cardiopulmonary bypass. Methods Included in this study were 90 children who underwent surgery for congenital heart diseases in Zhengzhou Children’s Hospital between June 2017 and March 2018. The children were divided into three groups by random number method (n=30 each) : the study group A, study group B and control group. When anesthesia became stable, the study group A was intravenously injected with dexmedetomidine, an α2-adrenoceptor agonist, at a dose of 1 μg/kg for more than 10 minutes and at a dose of 0.2 μg·kg-1·h-1 intraoperatively by intravenous infusion until the surgery was over. In the study group B, after induction anesthesia, dexmedetomidine was intravenously injected at a dose of 0.5 μg/kg for more than 10 minutes and at a dose of 0.1 μg·kg-1·h-1 intraoperatively by intravenous infusion until the surgery was over. The control group was given the same amount of normal saline by the same method. Before surgery (T1) , at the end of extracorporeal bypass (CPB) (T2) , 2 h after CPB (T3) , 6 h after CPB (T4) , and 24 h after CPB (T5) , blood samples were collected and tested for S-100 β protein, neuron enolase (NSE) , tumor necrosis factor-α (TNF-α) , interleukin-6 (IL-6) and NF-κB. Perioperative data were collected and recorded. The Denver Developmental Screening Test (DDST) and standardized clinical neurological function tests were performed to evaluate the neuropsychiatric status of the children at 1 day prior to surgery, at 1 and 7 days and 1 month after surgery. Children who appeared abnormal after surgery were further examined with head CT and EEG. Results There were no significant differences in general condition and surgical process between the three groups (all P>0.05) . At T1, there was no significant difference in S-100 β protein, NSE, TNF-α, IL-6 and NF-κB levels among the three groups (all P>0.05) . The control group showed higher levels of S-100 β protein and NSE at T2, T3, T4, and T5 compared with T1 (all P 0.05) . In the control group, 3 children presented with psychiatric symptoms and lower DDST score compared with before surgery. At 7 days after surgery, the DDST score resumed preoperative level, whereas head CT revealed signs of brain edema. At 1 month after surgery, these children underwent follow-up examination and presented normal head CT and EEG findings. Conclusion The use of α2-adrenergic receptor agonist in children with CPB may down-regulate the NF-κB expression, postoperative neurological complications, and ameliorate the cerebral injury caused by CPB. Key words: Adrenergic alpha-agonists; NF-kappa B; Heart defects, congenital; Children; Extracorporeal circulation; Brain injuries