Liver Tissue Blood Flow Measurement Using the Microbubble Method

首先用彩色微球法对兔模型进行脏器血流量测量，建立了微泡法测量肝组织血流量的方法。虽然机械通气减少了呼吸肌的工作负荷，但呼吸机的设置对呼吸肌和主要器官血流的影响研究很少。采用不同颜色微球的方法，测定了兔模型在不同机械通气设置下呼吸肌和主要器官的局部血流量。新西兰大白兔10只，用氯胺酮和异丙酚持续输注麻醉，然后行气管切开。经左颈总动脉将19G导管置入左心室，注入彩色微球。右股动脉插管采血。分别以0、6、12cmH2O的压力支持通气法(PSV)和6、12cmH2O的压力控制性通气法(PCV)观察肌松药后的横隔膜、肾脏和肝脏的局部血流变化。PSV6、PCV6、12cmH2O时隔膜血流量明显小于PSV0cmH2O时(P<0.05)。包括肾脏和肝脏在内的其他器官的血流在不同的呼吸机设置中没有明显变化。我们推测，隔膜内血流的差异是由于呼吸机和动物之间吸气不同步造成的。通过这项研究，我们可以建立一种测量器官血流量的方法。现在，我们正在尝试建立微气泡法来测量局部肝组织的血流量，并将彩色微球法测得的值作为对照。

At first organ blood flow measurements were conducted in a rabbit model using the colored-microsphere method to establish the liver tissue blood flow measurement by the micobubble method. Although mechanical ventilation reduces the respiratory muscle workload, the effects of ventilatory settings on blood flows of respiratory muscle and major organs have been little studied. Using the different-colored microspheres method, we measured the regional blood flow of respiratory muscle and major organs at different mechanical ventilatory settings in a rabbit model. Ten New Zealand white rabbits were anesthetized by continuous infusion of ketamine and propofol and then tracheostomized. A 19G catheter was inserted into the left ventricle via the left carotid artery to inject colored microspheres. The right femoral artery was cannulated for blood sampling. The regional blood flows in diaphragm (Diaphcost, crur), kidney and liver were studied during pressure support ventilation (PSV) of 0, 6, 12 cmH_2O and then pressure controlled ventilation (PCV) of 6 and 12 cmH_2O after the administration of muscle relaxant. Blood flows in diaphragm during PSV6, PCV 6, 12cmH_2O were significantly smaller than that during PSV0cmH_2O (p<0.05). Blood flows in other organs including kidney and liver did not change significantly among ventilatory settings. We speculate that the difference of blood flow in diaphragm was derived from the inspiratory asynchrony between the ventilator and the animal. With this study we could establish a method to measure organ blood flow. Now we are trying to establish the microbubble method to measure regional liver tissue blood flow using the values measured by the coloredmicrosphere method as control values.