体外循环围术期冠状微循环的观测和意义

目的 :建立活体心脏微循环的观测方法 ,研究猪体外循环围术期冠状微循环的变化规律 ,探讨其临床意义。方法 :小型猪 12头建立体外循环 ,心脏停跳 45min ,再灌注 12 0min。以右心耳的心外膜作为微循环观测窗。分别于体外循环转流前、心脏停跳前、主动脉开放后 5、3 0、60和 12 0min六个时间点 ,用接触式显微镜连接在电视监测器屏幕上观测冠状微血管形态和微血流的动态变化 ;应用激光多普勒微循环血流计测定心肌微区灌流量。结果 :猪体外循环心肌再灌注后 5～60min ,冠状微动脉口径较缺血前显著缩小 (P <0 .0 1) ,微血管中出现搏动性颗粒状血流 ,并有血浆与血细胞分离现象 ,提示有明显的红细胞聚集与毛细血管前括约肌痉挛。再灌注 5～ 3 0min ,心肌微区灌流量亦较缺血前下降 (P <0 .0 5 )。结论 :体外循环心肌缺血 再灌注后出现了冠状微血管痉挛、微血流瘀滞和心肌微区灌流量的下降 ,冠状微循环障碍与体外循环术后心功能不全有一定的相关关系。

Observation of Coronary Microcirculation During Peri-Operative Period Asssociated with Cardiopulmonary Bypass

Objective: To establish a method to observe the dynamic changes of coronary microcirculation during peri operative period associated with cardiopulmonary bypass(CPB)in an in vivo porcine model.Method: Twelve pigs were performed a standard CPB.The hearts were arrested for 45 minutes followed with 120 minutes' reperfusion.Coronary microvascular perfusion,coronary arterial microvessel diameter flowmeter and a contact microscope with TV monitor on six consecutive point of time,which were before CPB,10 minutes after CPB before aortic cross clamped,5,30,60 and 120 minutes after reperfusion.Results: Coronary microvascular perfusion was markedly decreased five to thirty minutes after the heart was reperfused( P<0.05 ).Coronary arterial microvessels became much thinner five to sixty minutes after reperfusion( P<0.01 )and pulsatile flow appeared in the reperfusion period when blood flow status was granular,separation of plasma and blood cell could be seen,indicated aggregation of erythrocytes and spasm of precapillary sphincter.Conclusion: Coronary microcirculation disorders do exist during myocardial ischemia reperfusion associated with CPB.The poor postoperative heart function with CPB has relationship with coronary microcirculation disrders.