Objective To investigate the protective effects of different maintenance doses of dexmedetomidine on brain tissues in surgical patients with craniocerebral injury.Methods A total of 160 cases of craniocerebral injury were divided into group A,group B, group C and group D,with 40 cases in each group.Group A,group B and group C were given intravenous infusion of dexmedetomidine with a loading dose of 1 μg/kg at 10 minutes before induction of anesthesia,then received the infusion of 0.2 μg/(kg·h),0.4 μg/(kg·h) and 0.6 μg/(kg·h) of dexmedetomidine respectively until 40 minutes before the end of surgery,and group D was infused with an equivalent volume of normal saline.Venous blood and arterial blood samples were collected from the patients for blood gas analysis before dexmedetomidine infusion(T0),after 1 h of operation(T1),right after operation(T2) and 72 h of operation(T3) respectively,the levels of jugular venous oxygen saturation(SjvO2),arterial-jugular venous oxygen content difference(Da-jvO2) and cerebral extraction rate of oxygen(CERO2) were calculated,and the levels of serum neuron specific enolase(NSE) and S-100β protein were determined. Results The levels of SjvO2,Da-jvO2and CERO2at T1,as well as the levels of serum NSE and S-100β protein at T1to T3,were lower in group A,B or C compared to the levels in group D(all P<0.05),the level of SjvO2at T1,the levels of Da-jvO2and CERO2at T1,and the levels of serum NSE and S-100β protein at T1to T3were lower in group B or C compared to the levels in group A(all P <0.05),but no significant differences were observed in the indices above between group B and group C(P>0.05).Heart rate at T1in group C was lower than that in the other 3 groups(P<0.05).Conclusion Dexmedetomidine can improve patients′cerebral oxygen metabolism and has some protective effects on brain when applied to surgery for craniocerebral injury,probably achieving a better efficacy with a loading dose of 1 μg/kg and a maintenance doses of 0.4 μg/(kg·h).%目的 探讨不同维持剂量右美托咪定对颅脑损伤手术患者脑组织的保护作用.方法 将160例颅脑损伤患者分为A组、B组、C组及D组,每组40例.A组、B组、C组均在麻醉诱导前10 min静脉输注右美托咪定1 μg/kg的负荷剂量,随后分别以0.2 μg/(kg·h)、0.4 μg/(kg·h)、0.6 μg/(kg·h)的速度输注直至手术结束前40 min,D组给予输注等量生理盐水.分别在右美托咪定输注前(T0)、手术开始后1 h(T1)、术毕(T2)和术后72 h(T3)采集患者静脉血及桡动脉血进行血气分析,计算颈内静脉血氧饱和度(SjvO2)、动脉-颈内静脉血氧含量差值(Da-jvO2)及脑氧摄取率(CERO2),并测定血清神经元特异性烯醇化酶(NSE)和S-100β蛋白水平.结果 A、B、C组T1的SjvO2T1Da-jvO2、CERO2及T1~T3血清NSE、S-100β蛋白水平低于D组(均P<0.05),B、C组T1的SjvO2高于A组,T1的Da-jvO2、CERO2及T1~T3的血清NSE、S-100β水平低于A组(均P<0.05),但B、C组间以上指标比较差异无统计学意义(P>0.05).C组T1的心率低于其他3组(P<0.05).结论 在颅脑损伤手术中应用右美托咪定能够改善患者的脑氧代谢,具有一定的脑保护作用,且以1.0 μg/kg为负荷量时,0.4 μg/(kg·h)的维持剂量效果可能最佳.
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