Assessment of the total artificial heart (TAH) pulsatility: the coalition between pulsatility and ejection time in TAH in vitro study.
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.
Nakata
K i
Ki
Department of Surgery, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030 USA.
Ohashi
Y
Y
Muller
J
J
Gleuck
J
J
Nose
Y
Y
D001696:Biomechanical Phenomena; D004389:Durable Medical Equipment; D006354:Heart, Artificial / Q000592:standards; D006801:Humans; D066298:In Vitro Techniques; D011673:Pulsatile Flow; D013318:Stroke Volume