Jaron D, Moore T W, He P
Ann Biomed Eng. 1985;13(2):155-75. doi: 10.1007/BF02584236.
The effectiveness of intraaortic balloon pumping was investigated by using a lumped parameter model of the cardiovascular/assist device system. The model consists of a time-varying elastance left ventricular simulation, a 2-element windkessel arterial simulation, and an RC venous return and pulmonary simulation. The four major hemodynamic variables, stroke volume (SV), aortic mean diastolic pressure (MDP), tension time index (TTI), and aortic end diastolic pressure (EDP), were divided into two categories related to system energy supply and demand: "external" and "internal" variables. The effects of balloon pumping on these variables can be described by closed-form equations that yield an optimal solution. The model prediction suggests that, in the ideal case, optimization of balloon pumping calls for instantaneous inflation of the balloon to maximum volume at end systole and instantaneous complete deflation at end diastole. For finite inflation/deflation rates, the optimal time for the start of inflation is end systole. Deflation timing, however, involves a tradeoff between maximizing the external variables and minimizing the internal variables. These predictions were tested using a nonlinear digital computer model. The results also suggest that when SV is not being monitored, optimal inflation timing can be controlled from the measurements of TTI or pulmonary venous pressure; optimal deflation timing can be controlled by a weighted combination of MDP and EDP.
通过使用心血管/辅助装置系统的集总参数模型，研究了主动脉内球囊反搏的有效性。该模型由一个时变弹性左心室模拟、一个双元件风箱动脉模拟以及一个RC静脉回流和肺模拟组成。四个主要的血流动力学变量，即每搏输出量（SV）、主动脉平均舒张压（MDP）、张力时间指数（TTI）和主动脉舒张末期压力（EDP），被分为与系统能量供需相关的两类：“外部”和“内部”变量。球囊反搏对这些变量的影响可用能得出最优解的闭式方程来描述。模型预测表明，在理想情况下，球囊反搏的优化要求在收缩末期将球囊瞬间充至最大容积，并在舒张末期瞬间完全放气。对于有限的充/放气速率，充气开始的最佳时间是收缩末期。然而，放气时间涉及在最大化外部变量和最小化内部变量之间进行权衡。使用非线性数字计算机模型对这些预测进行了测试。结果还表明，当不监测SV时，可根据TTI或肺静脉压力的测量来控制最佳充气时间；最佳放气时间可通过MDP和EDP的加权组合来控制。
