We describe an in vitro model of the Fontan circulation with respiration to study subdiaphragmatic venous flow behavior. The venous and arterial connections of a total cavopulmonary connection (TCPC) test section were coupled with a physical lumped parameter (LP) model of the circulation. Intrathoracic and subdiaphragmatic pressure changes associated with normal breathing were applied. This system was tuned for two patients (5 years, 0.67 m2; 10 years, 1.2 m2) to physiological values. System function was verified by comparison to the analytical model on which it was based and by consistency with published clinical measurements. Overall, subdiaphragmatic venous flow was influenced by respiration. Flow within the arteries and veins increased during inspiration but decreased during expiration with retrograde flow in the inferior venous territories. System pressures and flows showed close agreement with the analytical LP model (p < 0.05). The ratio of the flow rates occurring during inspiration to expiration were within the clinical range of values reported elsewhere. The approach used to setup and control the model was effective and provided reasonable comparisons with clinical data.
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机译：我们描述了带呼吸的Fontan循环体外模型，以研究study下静脉血流行为。总腔肺连接（TCPC）测试部分的静脉和动脉连接与循环的物理集总参数（LP）模型耦合。施加与正常呼吸有关的胸腔内和dia下压力变化。该系统针对两名患者（5年，0.67 m 2 ； 10年，1.2 m 2 ）进行了生理学调整。通过与系统所基于的分析模型进行比较并与已发布的临床测量结果一致来验证系统功能。总体而言，dia下静脉血流受呼吸影响。在吸气过程中，动脉和静脉内的血流增加，而在呼气过程中，下静脉区域的逆行血流减少。系统压力和流量与分析型LP模型显示出紧密的一致性（p <0.05）。在吸气和呼气过程中发生的流速之比在其他地方报告的临床值范围内。用于建立和控制模型的方法是有效的，并提供了与临床数据的合理比较。
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