叶轮泵式全人工心脏的结构设计及流体力学特性

Design and hydrodynamic characteristics of rotary pump in total artificial heart

目的通过模型样机研制和流体力学特性测试,探索以叶轮式血泵为结构基础的新型可完全植入的全人工心脏。方法全人工心脏模型样机分为左心泵和右心泵2个基本单位。2血泵均采用叶轮泵,共同设置在球形外壳中。2半球形外壳由高分子材料经激光快速成型制成,球形腔内设置固定左右心泵后对合为球形外壳,表面由医用聚氨酯橡胶涂层,直径55mm,总质量150g左右。在体外模拟循环台上对左心泵和右心泵的流体力学特性进行测试,主要观测指标为泵的转速、输出压力、流量、能耗和效率。模拟循环装置由模拟左右心房、血泵、阻力调节器、流量计串联组成,采用30%甘油水溶液作为循环介质。通过调节阻力测定特定泵转速下压力和流量。结果体外模拟测试表明全人工心脏模型样机可满足血液动力学基本要求,左心泵在9000～13000r/min转速条件下可以达到5～7L/min流量和13.3kPa(100mmHg)的压力输出,右心泵在约1/2左心泵转速和4.00kPa(30mmHg)后负荷下达到相似流量,可分别满足体、肺循环的要求。在该工作负荷条件下,2血泵的总效率约为14%。结论轴流泵作为人工心脏的血泵单位,流体力学特性可达到全人工心脏的基本要求。

Objective To develop a total artificial heart with rotary blood pumps by establishing and testing the hydrodynamic characteristic of a prototype. Methods The prototype of total artificial heart consisted of 2 rotary pumps,functioning for left and right heart pump respectively. The total weight of the total artificial heart （TAH） ,with a diameter of 55 mm, was 150 g. In vitro testing in a mock circuit was conducted to evaluate left and right heart pump performance. The main constituents were the pumps,2 reservoir tanks mocking right and left atria,flow meters,2 pressure gauges,and the resistance. The 30 % glycerol solution was used as the circulating media. Pump flow rate was measured by manual regulating the resistance to change the pressure for a given rotational speed. Results In vitro performance tests indicated that the prototype of total artificial heart achieved the required specifications. The left pump of the artificial heart worked at a speed of 9 000 - 13 000 r/min ,with a flow rate of 5 - 7 L/min against 13.3 kPa （ 100 mmHg） afterload throughout a mocking test. The right pump worked at about 1/2 of that speed to achieve the same flow rate against 4.00 kPa （30 mmHg） afterload. The observed efficiency of the artificial heart was 14 %. Conclusion The axial flow pump demonstrates acceptable hemodynamic characteristics for performance as a total artificial heart.