临终前心腔内自发性回声显影

Spontaneous Echo Contrast in Cardiac Chambers During Cardiac Arrest

犬15只,麻醉后以2mg/(min·kg)的速度静脉输入1％～2％氯化钾溶液,犬心率变慢直至停搏(平均约5小时)。随血钾浓度升高,各腔室逐渐扩大,血流逐渐迟缓。于心脏停搏前,超声心动图心尖四腔面可见右房、右室、左房及左室内出现缓慢活动的回声云团。如紧急抢救心脏及时复跳,则该回声云团便随之消失。尸检时,发现心腔内血液均呈液态。临终前心腔内自发回声显像是由于血流迟缓,促使红细胞叠加,超过超声显像力的最低阈值,为超声所探及而呈现密集回声。红细胞叠加,势必使气体交换的总有效面积减小,造成组织和器官的缺氧和酸中毒。提示心肺复苏的关键是心脏及时复跳。

Fifteen anesthetized dogs were infused with solution of 1%-2% KCI at a speed of 2mg/min/ kg,their heart rates slowed down gradually till cardiac arrest. Plasma K+ concentration increased graduuliy. four chambers became enlarged and blood flow slowed- 2-D echocardiography showed spontaneous echo contrast (SEC) appearing in the RA,RV,LA and LV,which would disappear if the heart beat restored- The blood in the chambers was still liquid without thrombosis at autopsy. The resuits supported that the mechanism of SEC was RBC rouleau formation and suggested that the decrease in effective surface of gas exchange may result in anoxia and acidosis,and finally lead to cell death.