Simulated experiments effects of intrathoracic pressure change on hemodynamics three models that simulated the anatomic arrangement of the venous return systems and chest cavity were established to investigate the hydromechanic principle of the different influence of the itpc on the ventricular fillings . effects of intrathoracic pressure change on the motion of interventricular septum ( ivs ) acuson ' s sequoia 512 ultrasonographic system was used in this study to record the m - mode and two - dimensional cineloop images of the simulated interventricular septum movement with different intrathoracic pressure changes 指标观测观察并记录外周静脉压和模拟胸腔压力分别变化及同时变化时，模拟右心室的容积变化；观察并记录模拟胸腔压力变化时，模拟肺血管床和左心室内压力的变化；用sequoia512超声心动图仪观察胸腔压力变化对模拟心脏室间隔运动的影响。
