右美托咪定对体外循环法洛四联症矫正术患儿的脑保护效应

Cerebral protective effect of dexmedetomidine in pediatric patients undergoing correction of tetralogy of Fallot with cardiopulmonary bypass

目的：评价右美托咪定对体外循环（ CPB）法洛四联症矫正术患儿的脑保护效应。方法择期CPB法洛四联症矫正术患儿60例，性别不限，年龄11个月～14岁，BMI 9．8～21．4 kg∕m2， ASA分级Ⅱ或Ⅲ级，采用随机数字表法，将其分为2组（ n＝30）：生理盐水组（ NS组）和右美托咪定组（ Dex组）。 Dex组于常规麻醉诱导前经10 min静脉输注右美托咪定0．5μg∕kg，继之以0．5μg·kg-1·h-1的速率输注至术毕；NS组以等容量生理盐水替代。于麻醉诱导前（ T0）、麻醉诱导后10 min（ T1）、复温至36℃（ T2）、CPB停机1 h（ T3）、6 h（ T4）、24 h（ T5）、48 h（ T6）和72 h（ T7）时采集桡动脉和颈内静脉球部血样行血气分析，记录颈静脉球部血氧饱和度（ SjvO2）、颈静脉球部血氧分压（ PjvO2），计算脑氧摄取率（ CERO2）和脑动静脉血氧含量差（ Da-jvO2）；于T0、T3～T7时采用ELISA法检测血清S-100β蛋白和神经元特异性烯醇化酶（ NSE）浓度。记录机械通气时间、ICU停留时间及术后并发症的发生情况。结果与T0时比较，NS组和Dex组T3～7时血清S-100β蛋白和NSE浓度升高，T1～2时SjvO2和PjvO2升高、CERO2和Da-jvO2降低（ P＜0．01）。与NS组比较，Dex组T3～7时血清S-100β蛋白和NSE浓度降低（ P＜0．01），术后机械通气时间、ICU停留时间及窦性心动过缓、低血压、再次气管插管发生率比较差异无统计学意义（ P＞0．05）。2组脑氧代谢指标均在正常范围，组间比较差异无统计学意义（ P＞0．05）。结论常规麻醉诱导前静脉输注右美托咪定0．5μg∕kg，随后以0．5μg·kg－1·h－1输注至术毕对CPB法洛四联症矫正术患儿具有脑保护效应。

Objective To evaluate the cerebral protective effect of dexmedetomidine in the pediatric patients undergoing correction of tetralogy of Fallot with cardiopulmonary bypass （ CPB） . Methods Sixty pediatric patients of both sexes, aged 11 months-14 yr, with body mass index of 9.8-21.4 kg∕m2 , of ASA physical status Ⅱ or Ⅲ, scheduled for elective correction of tetralogy of Fallot with CPB, were randomly divided into 2 groups （n=30 each） using a random number table： normal saline group （group NS） and dexmedetomidine group （group Dex）. Dexmedetomidine was infused intravenously at a dose of 0.5 μg∕kg over 10 min before induction of anesthesia, followed by 0.5μg·kg-1 ·h-1 infusion until the end of surgery. The equal volume of normal saline was given instead in group NS. Before induction of anesthesia （ baseline, T0 ） , and at 10 min after induction （ T1 ） , after re-warming to 36℃ （ T2 ） , and at 1, 6, 24, 48 and 72 h after termination of CPB （ T3-7 ） , blood samples were obtained from the radial artery and jugular venous bulb for blood gas analysis, jugular venous oxygen saturation （ SjvO2 ） and jugular venous oxygen partial pressure （ PjvO2 ） were recorded, and cerebral O2 extraction rate （ CERO2 ） and arteriovenous blood O2 content difference （ Da-jvO2 ） were calculated. The concentrations of S-100βprotein and neuron-specific enzyme （ NSE） in serum were determined by enzyme-linked immunosorbent assay at T0 and T3-7 . The time for mechanical ventilation, duration of intensive care unit stay, and development of postoperative complications were recorded. Results Compared with the baseline value at T0 , the serum concentrations of S-100β and NSE were significantly increased at T3-7 , and SjvO2 and PjvO2 were increased, and CERO2 and Da-jvO2 were decreased at T2 in both groups. Compared with group NS, the serum concentrations of S-100β and NSE were significantly decreased at T3-7 , and no significant changes were found in the time for mechanical ventilation, duration of intensive care unit stay, and incidence of sinus bradycardia, hypotension, and re-intubation in group Dex. The parameters of cerebral oxygen metabolism were all within the normal range in both groups, and there was no significant difference between the two groups. Conclusion Dexmedetomidine infused intravenously at a dose of 0. 5 μg∕kg before induction of anesthesia, followed by 0.5μg·kg-1 ·h-1 infusion until the end of surgery, provides cerebral protection in the pediatric patients undergoing correction of tetralogy of Fallot with CPB.