School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, Australia.
Artif Organs. 2013 Aug;37(8):E139-44. doi: 10.1111/aor.12110. Epub 2013 Jul 4.
On average, an end-stage renal disease patient will undergo hemodialysis (HD) three or four times a week for 4-5 h per session. Any minor imperfection in the extracorporeal system may become significant in the treatment of these patients due to the cumulative exposure time. Recently, air traps (a safety feature of dialysis systems) have been reported to be inadequate in detecting microbubbles and may even create them. Microbubbles have been linked to lung injuries and damage to the brain in chronic HD patients; therefore the significance of microbubbles has been revisited. Bubbles may originate at the vascular access sites, sites of local turbulent blood flow, the air trap, or in the bloodlines after priming with saline prior to use. In this paper, computational fluid dynamics is used to model blood flow in the air trap to determine the likely mechanisms of microbubble dynamics. The results indicate that almost all bubbles with diameters less than 50 μm and most of the bubbles of 50-200 μm pass through the air trap. Consequently, the common air traps are not effective in removing bubbles less than 200 μm in diameter.
平均而言，终末期肾病患者每周接受血液透析 (HD) 三到四次，每次治疗 4-5 小时。由于这些患者的累积暴露时间，体外系统中的任何微小缺陷在治疗中都可能变得非常重要。最近，据报道，空气阱（透析系统的安全功能）在检测微泡方面不够充分，甚至可能会产生微泡。微泡已被证明与慢性血液透析患者的肺损伤和大脑损伤有关；因此，微泡的意义已被重新审视。气泡可能起源于血管通路部位、局部湍流血流部位、空气阱部位，或在使用前用生理盐水预充后在血液管路中产生。在本文中，使用计算流体动力学来模拟空气阱中的血液流动，以确定微泡动力学的可能机制。结果表明，直径小于 50μm 的几乎所有气泡和 50-200μm 的大部分气泡都通过了空气阱。因此，常见的空气阱不能有效地去除直径小于 200μm 的气泡。
