Nakazawa T, Makinouchi K, Takami Y, Glueck J, Takatani S, Nosé Y
Department of Surgery, Baylor College of Medicine, Houston, TX 77030, USA.
Artif Organs. 1996 Mar;20(3):252-7. doi: 10.1111/j.1525-1594.1996.tb04434.x.
Blood trauma is one of the important performance parameters of centrifugal pumps. To investigate the blood trauma induced by these pumps, in vitro hemolysis tests have become an important procedure and are increasingly used for pump development and comparisons. The Baylor compact eccentric inlet port (CIE) centrifugal blood pump was developed as a long-term centrifugal ventricular assist device (VAD) as well as a cardiopulmonary bypass pump (CPB). The Baylor CIE pump incorporates a seal-less design with a blood stagnation-free structure. This pump can provide flows of 5 L/min against 350 mm Hg of total pressure head at 2,600 revolutions per minute. The pump impeller is magnetically coupled to the driver magnet in a seal-less manner. The latest hemolysis study revealed that hemolysis may be affected by the gap distance between the driver and the impeller magnet. The purpose of this study was to verify the effect of the magnetic coupling distance on the normalized index of hemolysis (NIH) with the CIE model and to obtain an optimal gap distance. The NIH value was clearly decreased by alteration of the magnetic coupling distance from 7.7 to 9.7 mm in CPB and left ventricular assist device (LVAD) conditions. The NIH, when using the pump as an LVAD condition, was reduced to a level of 0.0056 from 0.095 when the magnetic coupling distance was extended. The same results were also obtained when the pumps were used in a CPB condition. The magnetic coupling distance is an important factor for the CIE model in terms of hemolysis. Different coupling forces effect the bearings and impeller stability. These results suggest that an optimal driving condition with a proper magnetic coupling and an optimal force between the impeller and driver is necessary to develop an atraumatic centrifugal pump.
血液损伤是离心泵的重要性能参数之一。为了研究这些泵引起的血液损伤，体外溶血试验已成为一项重要程序，并越来越多地用于泵的开发和比较。贝勒紧凑型偏心入口（CIE）离心泵被开发用作长期离心式心室辅助装置（VAD）以及体外循环泵（CPB）。贝勒CIE泵采用无密封设计和无血液停滞结构。该泵在每分钟2600转时可提供5升/分钟的流量，总压头为350毫米汞柱。泵叶轮与驱动磁体以无密封方式磁耦合。最新的溶血研究表明，溶血可能受驱动磁体与叶轮磁体之间的间隙距离影响。本研究的目的是验证CIE模型中磁耦合距离对溶血归一化指数（NIH）的影响，并获得最佳间隙距离。在体外循环和左心室辅助装置（LVAD）条件下，将磁耦合距离从7.7毫米改变为9.7毫米时，NIH值明显降低。当将该泵用作LVAD时，磁耦合距离延长后，NIH从0.095降至0.0056水平。在体外循环条件下使用该泵时也得到了相同结果。就溶血而言，磁耦合距离是CIE模型的一个重要因素。不同的耦合力会影响轴承和叶轮的稳定性。这些结果表明，开发无损伤离心泵需要具有适当磁耦合和叶轮与驱动器之间最佳力的最佳驱动条件。
