Biglino Giovanni, Kolyva Christina, Khir Ashraf W
Brunel Institute for Bioengineering, Brunel University, Uxbridge, UK.
Int J Artif Organs. 2012 Jan;35(1):15-24. doi: 10.5301/ijao.5000015.
Despite decades of successful clinical use of the intra aortic balloon pump (IABP), certain aspects of its operation are not yet fully understood. This work aims to investigate in vitro the mechanism underlying balloon inflation and deflation with varying assisting frequency and operating angle with respect to the horizontal, by studying the corresponding pressure and wave energy changes.
A mock circulatory system (MCS), with physiological distribution of peripheral resistance and compliance, presented a controllable test bed. We used Wave Intensity Analysis (WIA) to identify balloon-generated waves and quantify their energy. Conventional hemodynamic parameters were also calculated. Tests were repeated at varying operating angles (0°-45°), resembling the semi-recumbent position in the ICU, and at different assisting frequencies (1:1, 1:2, 1:3). Two balloons (25 cc and 40 cc in volume) were tested.
The main waves associated with counterpulsation were identified as a backward compression wave associated with balloon inflation and a backward expansion wave associated with balloon deflation. Results showed that the IABP inflation and deflation benefits are reduced with increasing angle, in terms of the size of the inflation and deflation waves as well as in terms of diastolic pressure augmentation and end-diastolic pressure reduction. Both WIA findings and pressure parameters indicated 1:1 as the most effective mode of pumping.
This study shows that, in vitro, a greater benefit of counterpulsation can be achieved in the horizontal position at 1:1 assisting frequency, with a good correlation between wave and pressure results.
尽管主动脉内球囊反搏（IABP）已成功临床应用数十年，但其操作的某些方面尚未完全明了。本研究旨在通过研究相应的压力和波能变化，在体外探究球囊充气和放气的机制，以及不同辅助频率和相对于水平方向的操作角度的影响。
一个具有外周阻力和顺应性生理分布的模拟循环系统（MCS）提供了一个可控的试验平台。我们使用波强度分析（WIA）来识别球囊产生的波并量化其能量。还计算了传统的血流动力学参数。在类似于重症监护病房半卧位的不同操作角度（0°-45°）以及不同辅助频率（1:1、1:2、1:3）下重复进行测试。测试了两个球囊（体积分别为25 cc和40 cc）。
与反搏相关的主要波被识别为与球囊充气相关的向后压缩波和与球囊放气相关的向后膨胀波。结果表明，随着角度增加，IABP充气和放气的益处会降低，无论是充气和放气波的大小，还是舒张压升高和舒张末期压力降低方面。WIA结果和压力参数均表明1:1是最有效的泵血模式。
本研究表明，在体外，在水平位置以1:1辅助频率进行反搏可获得更大益处，波和压力结果之间具有良好的相关性。
