小型幼猪体外循环模型灌注流量对脑血流灌注的影响

The pilot exploration of cerebral perfusion in unique piglet's extracorporeal circulation model

目的建立幼猪体外循环(cardiopulmonary bypass,CPB)模型,观察CPB灌注流量发生改变期间,脑灌注流量和局部脑氧饱和度(regional cerebral oxygen saturation,rSO_2)的变化,从而探索CPB灌注流量对脑血流量自我调节的影响,以期为婴幼儿CPB合理的灌注管理、预防脑缺血提供理论依据。方法 12只幼猪按照随机表分为3组,对照组、高流量组(H组)、低流量组(L组)。建立单泵双管CPB灌注模型,用血流检测仪直接检测灌注管路流量反映不同流量下脑动脉内血液灌注的变化,并采用近红外分光广度检测技术(near infrared reflectance spectroscopy,NIRS)监测幼猪CPB模型中rSO_2的变化。在CPB开始前10 min、CPB开始后10 min、升主动脉阻断后30 min和升主动脉开放后10 min 4个时间点检测血清S100钙结合蛋白B(S100 B)浓度。分别进行苏木精-伊红(HE)染色、尼氏染色观察海马CA区组织学变化。结果在主动脉阻断期间,H组脑灌注流量[(30.8±9.9)mL/(kg·min)]较L组[(19.0±7.4)mL/(kg·min)]有增高趋势但无统计学差异(P=0.072),且该时间点H组rSO_2值(52.65%±3.1%)显著高于L组(47.3%±3.3%)(P<0.05)。海马组织学变化及血清S100 B蛋白水平无组间差异。结论在小型猪体外循环灌注模型中,脑动脉内流量及局部脑氧饱和度监测提示脑血流压力/血流自我调节减弱,高流量组脑灌注效果优于低流量灌注。

Objective In order to provide the basic theory for reasonable management of cerebral perfusion and avoid cerebral ischem ia,this study was designed to establish one unique piglet extracorporeal circulation model and explore real-time monitoring of the dynamic changes in cerebral perfusion and regional cerebral oxygen saturation(rS〇2)during different stages of cardiopulmonary bypass(C PB).Methods Twelve piglets were divided into 3 groups randomly(几=4):control group,high blood flow group(H group)and low blood flow group(L group).A unique double arterial line with single pump was established in this piglet’s model.Cerebral flow rates were monitored using TS410 transit-time tubing flowmeters(Transonic Systems Inc.,Ithaca,N Y).Regional cerebral oxygen saturation(rS〇2)was monitored simultaneously as one of parameters of cerebral autoregulation.Arterial samples were drawn to measure the concentrations of S100 protein.Hematoxylin-eosin(H E)and Nissl staining were performed to detect morphologic characteristics of hippocampus.Results During cross-clamping of CPB,cerebral blood flow in L group[(19.0±7.4)mL/(kg?m in)]was lower than that in H group[(30.8±9.9)m^(k g?m in)](_P=0.072),and the rS〇2 in L group(47.3%±3.3%)was lower than that in H group(52.6%±3.1%)(P<0.05).There were no significant difference in HE and Nissl staining in hippocampus neuron among the three groups.Conclusions The current study demonstrated that the impairment of cerebral autoregulation and cerebral perfusion was determined by the whole blood flow of extracorporeal circulation.High blood flow in extracorporeal circulation had better cerebral perfusion during cross-clamping than low blood flow.