| Artificial blood pump, i.e., artificial heart, is a mechanical device which is usedto substitute the natural heart in totally or partially, provide the motive power forblood circulation. It is placed in vivo or in vitro. The artificial heart is classified byuse as the left ventricular assist device, the right ventricular assist device and totallyartificial heart. A complete blood pump system should include the liquid drivingdevice, the monitoring system, controlling mechanism, the energy supply mechanism(battery) and other components. The artificial blood pump is a liquid driving device asthe core component in system, its output needs to satisfy the requirements of thephysiologic properties in the physical body, and then it needs to have some featuressuch as the stable performance, low hemolytic effect and good biocompatibility. Atthe same time, to meet the portability and implantation needs the pump in a smallvolume and light weight.This paper puts forward a program which uses the piezoelectric pump to driveblood. The piezoelectric pump excited by the converse piezoelectric effect. It’s a newkind of pumps which has no electromagnetic interference on the surroundingenvironment during working process, especially there are no rotating parts and lowdriving speed in this pump which has a small impact during the blood drive processand prevents the blood from coagulating as well as the destruction of blood cells.Combines the requirements of the National Natural Science Foundation of ChinaProject " Multi-cavity Piezoelectric Blood Pump as the Basis of Theoretical andExperimental Research "(81171481), this paper research on a new type artificialblood pump system used in the preclinical experimental which has completeintellectual property rights. Based on the former achievement, this paper conductedmainly experiments integrated with theoretical analysis and simulation.The paper analyzed and tested the influence of structural parameters on theperformance of the piezoelectric blood pump, such as the height of the chamber, depthof the diversion channel, diameter of inlet and outlet, form of the check valve.Firstly, the factors that affect the performance of the blood pump are analyzed bytheoretical modeling. Secondly, blood pumps with different structural parameters arestudied through the experiments by changing single factors, and the optimal structureis determined on the basis of the experimental results. Finally, the circulatory system in vitro is built to test and analyze the prototype. A cardiopulmonary bypass systemwith the piezoelectric blood pump experimental prototype was established, theAutomated Hematology Analyzer is utilized as detection device to test thebiochemical characteristic of pig blood which has cycled0.5hour,1hour and1.5hours. The results show that with the increasing duration of cycle the red blood cellcount, white blood cell count, LY, NE, hematocrit and free hemoglobin concentrationare decreased, that is to say the blood cells were damaged. But the extent of thedamage was significantly lower than traditional continuous blood pump. It was foundthat the damaged blood cells form a flocculent coagulum in the corners of the innerpump wall. The theoretical analysis shows that the damage causes the turbulenceeffects driven by too sudden expansion of the flow cross-sectional in the area. Aftercardiopulmonary bypass found that the flocculent coagulum on cantilever valve is lessthan wheel valve, the extent of damage to blood cells from the cantilever valvestructure is less than the wheel valve. |
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