Mechanical Engineering, Koc University, Turkey.
School of Medicine, Medipol University, Turkey.
J Biomech. 2021 May 24;121:110382. doi: 10.1016/j.jbiomech.2021.110382. Epub 2021 Apr 15.
Venovenous extracorporeal membrane oxygenation (VV-ECMO) is the preferred surgical intervention for patients suffering from severe cardiorespiratory failure, also encountered in SARS-Cov-2 management. The key component of VV-ECMO is the double-lumen cannula (DLC) that enables single-site access. The biofluid dynamics of this compact device is particularly challenging for neonatal patients due to high Reynolds numbers, tricuspid valve location and right-atrium hemodynamics. In this paper we present detailed findings of our comparative analysis of the right-atrial hemodynamics and salient design features of the 13Fr Avalon Elite DLC (as the clinically preferred neonatal cannula) with the alternate Origen DLC design, using experimentally validated computational fluid dynamics. Highly accurate 3D-reconstructions of both devices were obtained through an integrated optical coherence tomography and micro-CT imaging approach. Both cannula configurations displayed complex flow structures inside the atrium, superimposed over predominant recirculation regimes. We found that the Avalon DLC performed significantly better than the Origen alternative, by capturing 80% and 94% of venous blood from the inferior and superior vena cavae, respectively and infusing the oxygenated blood with an efficiency of more than 85%. The micro-scale geometric design features of the Avalon DLC that are associated with superior hemodynamics were investigated through 14 parametric cannula configurations. These simulations showed that the strategic placement of drainage holes, the smooth infusion blood stream diverter and efficient distribution of the venous blood capturing area between the vena cavae are associated with robust blood flow performance. Nevertheless, our parametric results indicate that there is still room for further device optimization beyond the performance measurements for both Avalon and Origen DLC in this study. In particular, the performance envelope of malpositioned cannula and off-design conditions require additional blood flow simulations for analysis.
静脉-静脉体外膜肺氧合（VV-ECMO）是治疗严重心肺衰竭患者的首选手术干预措施，在 SARS-CoV-2 管理中也会遇到这种情况。VV-ECMO 的关键组件是双腔管（DLC），它可实现单点进入。由于雷诺数高、三尖瓣位置和右心房血流动力学的原因，这种紧凑设备的生物流体动力学对新生儿患者来说尤其具有挑战性。在本文中，我们介绍了我们对 13Fr Avalon Elite DLC（作为临床首选的新生儿套管）与替代 Orig en DLC 设计的右心房血流动力学和突出设计特征的详细比较分析结果，使用经过实验验证的计算流体动力学。通过集成光学相干断层扫描和微 CT 成像方法，获得了这两种设备的高度精确的 3D 重建。两种套管构型都在心房内显示出复杂的流动结构，叠加在主要的再循环区域之上。我们发现 Avalon DLC 的性能明显优于 Orig en 替代方案，分别从下腔静脉和上腔静脉捕获 80%和 94%的静脉血，并以超过 85%的效率将含氧血液注入。通过 14 个参数化套管构型研究了与优越血液动力学相关的 Avalon DLC 的微观尺度几何设计特征。这些模拟表明，引流孔的策略性放置、平滑的输注血流转向器以及静脉血捕获区域在腔静脉之间的有效分配与强大的血流性能相关。然而，我们的参数结果表明，除了本研究中 Avalon 和 Orig en DLC 的性能测量之外，仍有进一步优化设备的空间。特别是，对于错位套管和非设计条件的性能包络，需要进行额外的血流模拟分析。
