Nakata K i, Ohashi Y, Muller J, Gleuck J, Nose Y
Department of Surgery, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030 USA.
Ann Thorac Cardiovasc Surg. 1998 Oct;4(5):275-9.
There are many types of pulsatile pumps with various pulsatile flow waveforms. These authors perceived that pulsatility was an important characteristic for a pulsatile pump. The effect of a total artificial heart (TAH) was estimated using a pulse power index (PPI) in a mock loop. This method helps in the development of a standard criterion for measurement of a pulsatile waveform. The pulsatility of the TAH was found to be useful as a physiological control method. At first the relationship between ejection time and dp/dt was examined and then the relation between PPI, ejection time and preload. The dp/dt was unchanged by ejection time and PPI was unchanged by preload. However, PPI was changed by the ejection time. There was an inverse correlation between ejection time and PPI (r = 0.80). The PPI at ejection time 150 msec was significantly higher than the other ejection time's PPI. These results suggest that the TAH should be driven with an ejection time of 150 msec, because this ejection time has a high pulsatility and can obtain a higher flow. This happens without increasing the dp/dt and this ejection time can be preplanned, because a fixed ejection time improves the durability of the actuator.
有许多类型的搏动泵，具有各种搏动血流波形。这些作者认为搏动性是搏动泵的一个重要特征。在模拟循环中使用脉冲功率指数（PPI）评估全人工心脏（TAH）的效果。这种方法有助于制定搏动波形测量的标准准则。发现TAH的搏动性作为一种生理控制方法是有用的。首先研究了射血时间与dp/dt之间的关系，然后研究了PPI、射血时间与前负荷之间的关系。dp/dt不受射血时间影响，PPI不受前负荷影响。然而，PPI受射血时间影响。射血时间与PPI之间存在负相关（r = 0.80）。射血时间为150毫秒时的PPI显著高于其他射血时间的PPI。这些结果表明，TAH应以150毫秒的射血时间驱动，因为这个射血时间具有较高的搏动性，并且可以获得更高的流量。这在不增加dp/dt的情况下发生，并且这个射血时间可以预先计划，因为固定的射血时间可以提高执行器的耐久性。
