The protective effect of dexmedetomidine against cerebral ischemic injury of patients undergoing cardiac valve replacement surgery with cardiopulmonary bypass

Abstract

Objective To evaluate the protective effect of dexmedetomidine against cerebral ischemic injury of patients undergoing cardiac valve replacement surgery with cardiopulmonary bypass (CPB).Methods Thirty patients undergoing cardiac valve replacement surgery were allocated randomly into group A and group B,15 cases each group.In group A,0.5 μg/kg dexmedetomidine was given as a loading dose,then maintained with the dose of 0.5 μg/(kg·h),In group B,the dexmedetomidine was insteaded by O.9％ sodium chloride.At T1-T7 time points,arterial and jugular venous blood were collected for blood gas analyses; At T1,T3,T5,T6 and T7 time points,Plasma concentration of S-100β and neuron specific enolase (NSE) were measured.Results There was no difference in SjvO2 and ERO2 between two groups at T1.In group A and B,the SjvO2 was (71.7 ± 6.2) ％ and (65.0 ± 6.1) ％ separately at T5 ; compared with group A,the SjvO2 in group B decreased significantly(P ＜0.05) ; In group A and B,the ERO2 was (27.9±7.2)％ and(33.8 ±7.6)％ separately at T5; compared with group A,the ERO2 in group B increased significantly(P ＜0.05); Compared with T1,the Plasma concentration of S-100β and NSE at T6 and T7 increased significantly in both two groups (P ＜ 0.01),especially in group B (P ＜ 0.05).Conclusion Dexmedetomidine can reduce cerebral oxygen uptake rate,avoid cerebral oxygen supply-demand imbalance and reduce cerebral ischemic injury in rewarming period during cardiopulmonary bypass in cardiac valve replacement surgery,which bring about certain cerebral protective effects for those patients. Key words: Dexmedetomidine; Cerebral oxygen metabolism; Cerebral protection; Neuron specific enolase; S-100β protein