Qian K X
Department of Biomedical Engineering, Shanghai Second Medical University, China.
Med Eng Phys. 1996 Jan;18(1):57-66. doi: 10.1016/1350-4533(95)00010-0.
The impeller blood pump with its simplicity has many advantages compared with the diaphragm pump, but the nonpulsatile property has limited its applications. To make the impeller pump pulsatile, many investigations have been made in vain because of resulting haemolysis. The author has succeeded in producing a pulsatile blood flow with a centrifugal pump, by means of the streamlined design of the impeller. The vane and shroud coincide with the blood stream surface in the pump, to eliminate the turbulence and stasis of the blood flow, which are the main factors in haemolysis and thrombosis. The pulsatility of the blood pressure and flow rate is achieved by changing the rotating speed of the impeller periodically, by introducing a square wave form voltage into the motor coil. The velocity variation of the blood cells due to the changing rotating speed of the impeller is minimized by using twisted impeller vanes, thus reducing the additional Reynolds shear, which causes the additional haemolysis in the pump. In vitro testing demonstrated that the haemolysis index of the pulsatile impeller pump is slightly higher than that of the author's nonpulsatile impeller pump but clearly less than that of other pulsatile blood pumps. The in vivo evaluations indicated that no blood damage occurred and that all haematological and biochemical data kept within a normal range during left ventricular assist experiments in calves for up to 11 days. A pulsatile impeller total heart has been developed. Two pumps are located on both sides of and driven by a d.c. motor. As the motor changes its rotating speed periodically, the left and right pumps eject the blood simultaneously, and the volume equilibrium of both pumps is achieved naturally. Acute biventricular assist experiments in pig confirmed that the device caused no blood damage.
叶轮血泵结构简单，与隔膜泵相比有许多优点，但非搏动性限制了其应用。为使叶轮泵产生搏动，人们进行了许多徒劳的研究，因为会导致溶血。作者通过叶轮的流线型设计，成功地用离心泵产生了搏动血流。叶片和护罩与泵内血流表面重合，以消除血流的湍流和停滞，而这是溶血和血栓形成的主要因素。通过向电机线圈引入方波电压，周期性地改变叶轮转速，实现血压和流速的搏动性。使用扭曲的叶轮叶片可将因叶轮转速变化导致的血细胞速度变化降至最低，从而减少额外的雷诺切应力，这种切应力会在泵内导致额外的溶血。体外测试表明，搏动性叶轮泵的溶血指数略高于作者的非搏动性叶轮泵，但明显低于其他搏动性血泵。体内评估表明，在对小牛进行长达11天的左心室辅助实验期间，未发生血液损伤，所有血液学和生化数据均保持在正常范围内。已开发出一种搏动性叶轮全人工心脏。两个泵位于直流电机两侧并由其驱动。随着电机周期性地改变转速，左右泵同时射出血液，且两泵的容积平衡自然实现。在猪身上进行的急性双心室辅助实验证实该装置不会造成血液损伤。
