Fulker David, Kang Martin, Simmons Anne, Barber Tracie
Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Australia.
Hemodial Int. 2013 Oct;17(4):602-11. doi: 10.1111/hdi.12029. Epub 2013 Mar 1.
The vascular access used in hemodialysis can suffer from numerous complications, which may lead to failure of the access, patient morbidity, and significant costs. The flow field in the region of the venous needle may be a source of damaging hemodynamics and hence adverse effects on the fistula. In this study, the venous needle flow has been considered, using three-dimensional computational methods. Four scenarios where the venous needle flow could potentially influence dialysis treatment outcome were identified and examined: Variation of the needle placement angle (10°, 20°, 30°), variation of the blood flow rate settings (200, 300, 400 mL/min), variation of the needle depth (top, middle, bottom), and the inclusion of a back eye in the needle design. The presence of the needle has significant effect on the flow field, with different scenarios having varying influence. In general, wall shear stresses were elevated above normal physiological values, and increased presence of areas of low velocity and recirculation-indicating increased likelihood of intimal hyperplasia development-were found. Computational results showed that the presence of the venous needle in a hemodialysis fistula leads to abnormal and potentially damaging flow conditions and that optimization of needle parameters could aid in the reduction of vascular access complications. Results indicate shallow needle angles and lower blood flow rates may minimize vessel damage.
血液透析中使用的血管通路可能会出现多种并发症，这可能导致通路失效、患者发病并产生高昂费用。静脉穿刺针区域的流场可能是造成血液动力学损伤的一个原因，进而对动静脉内瘘产生不利影响。在本研究中，采用三维计算方法对静脉穿刺针的血流情况进行了分析。确定并研究了静脉穿刺针血流可能影响透析治疗结果的四种情况：穿刺针放置角度的变化（10°、20°、30°）、血流速度设置的变化（200、300、400毫升/分钟）、穿刺针深度的变化（顶部、中部、底部）以及在穿刺针设计中加入侧孔。穿刺针的存在对流场有显著影响，不同情况的影响各不相同。一般来说，壁面剪应力高于正常生理值，并且发现低速和回流区域增多，这表明内膜增生发展的可能性增加。计算结果表明，血液透析动静脉内瘘中静脉穿刺针的存在会导致异常且可能具有损害性的血流状况，而优化穿刺针参数有助于减少血管通路并发症。结果表明，较小的穿刺针角度和较低的血流速度可能会将血管损伤降至最低。
