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):258-63. doi: 10.1111/j.1525-1594.1996.tb04435.x.
The pivot bearing centrifugal blood pump was developed as a long-term centrifugal ventricular assist device (VAD) as well as a cardiopulmonary bypass pump. This pivot bearing supported centrifugal pump with an eccentric port (CIE) incorporates a seal-less design with a blood stagnation-free structure. This pump can provide flows of 12 L/min against 650 mm Hg total pressure head at 3,600 rpm, and in a CPB condition 5 L/min against 350 mm Hg total pressure head at 2,600 rpm. Very recently, the pivot bearing system was modified to obtain a stable and smooth spinning movement. The material of the female pivot was changed from ceramic to polyethylene. Three kinds of bearings were tested simultaneously with bovine blood in two types of in vitro circuits to determine the blood damage from the bearings. Pressure differences across the pump (total head pressure, delta P) of 140 mm Hg (n = 12) and 330 mm Hg (n = 12) were examined. The normalized index of hemolysis (NIH) was slightly higher in a ball bearing (BB) pump than in a polyethylene bearing (PB) pump and statistically higher than the BioMedicus Pump (BP-80) on delta P of 140 mm Hg. When the delta P was at 330 mm Hg, a comparison between the three types of pumps revealed no difference in NIH. In addition, the primary vane of the impeller was redesigned to obtain an atraumatic structure. In the second study (n = 14), there was no difference in the NIH between BP-80 and the current model when the delta P was 300 mm Hg (0.019 +/- 0.002 vs. 0.027 +/- 0.006, p = 0.3) and/or when the delta P was 100 mm Hg (0.0008 +/- 0.0001 vs. 0.0014 +/- 0.0002, p = 0.07). The modified pivot bearing had an improved spinning condition and no change in hemolysis. A proper selection of pivot bearing materials is important to develop an atraumatic centrifugal pump. The modification of the bearing system and redesign of the vane enabled a compact centrifugal pump to become a reality.
枢轴轴承离心血泵是作为一种长期的离心式心室辅助装置（VAD）以及体外循环泵而开发的。这种带有偏心端口（CIE）的枢轴轴承支撑式离心泵采用了无密封设计和无血液停滞结构。该泵在3600转/分时可提供12升/分钟的流量，对抗650毫米汞柱的总压头；在体外循环条件下，在2600转/分时可提供5升/分钟的流量，对抗350毫米汞柱的总压头。最近，对枢轴轴承系统进行了改进，以获得稳定和平滑的旋转运动。母枢轴的材料从陶瓷改为聚乙烯。在两种体外循环回路中，同时用牛血对三种轴承进行了测试，以确定轴承造成的血液损伤。检查了泵两端140毫米汞柱（n = 12）和330毫米汞柱（n = 12）的压力差（总压头压力，ΔP）。在140毫米汞柱的ΔP下，球轴承（BB）泵的标准化溶血指数（NIH）略高于聚乙烯轴承（PB）泵，且在统计学上高于百多力泵（BP - 80）。当ΔP为330毫米汞柱时，三种泵之间的NIH比较没有差异。此外，对叶轮的主叶片进行了重新设计，以获得无创伤结构。在第二项研究（n = 14）中，当ΔP为300毫米汞柱（0.019±0.002对0.027±0.006，p = 0.3）和/或当ΔP为100毫米汞柱（0.0008±0.0001对0.0014±0.0002，p = 0.07）时，BP - 80与当前模型之间的NIH没有差异。改进后的枢轴轴承旋转条件得到改善，溶血情况没有变化。正确选择枢轴轴承材料对于开发无创伤离心泵很重要。轴承系统的改进和叶片的重新设计使紧凑型离心泵成为现实。
