Background Blood removal from cerebrospinal fluid (CSF) in post-subarachnoid hemorrhage patients may reduce the risk of related secondary brain injury. We formulated a computational fluid dynamics (CFD) model to investigate the impact of a dual-lumen catheter-based CSF filtration system, called Neurapheresis™ therapy, on blood removal from CSF compared to lumbar drain. Methods A subject-specific multiphase CFD model of CSF system-wide solute transport was constructed based on MRI measurements. The Neurapheresis catheter geometry was added to the model within the spinal subarachnoid space (SAS). Neurapheresis flow aspiration and return rate was 2.0 and 1.8 mL/min, versus 0.2 mL/min drainage for lumbar drain. Blood was modeled as a bulk fluid phase within CSF with a 10% initial tracer concentration and identical viscosity and density as CSF. Subject-specific oscillatory CSF flow was applied at the model inlet. The dura and spinal cord geometry were considered to be stationary. Spatial–temporal tracer concentration was quantified based on time-average steady-streaming velocities throughout the domain under Neurapheresis therapy and lumbar drain. To help verify CFD results, an optically clear in vitro CSF model was constructed with fluorescein used as a blood surrogate. Quantitative comparison of numerical and in vitro results was performed by linear regression of spatial–temporal tracer concentration over 24-h. Results After 24-h, tracer concentration was reduced to 4.9% under Neurapheresis therapy compared to 6.5% under lumbar drain. Tracer clearance was most rapid between the catheter aspiration and return ports. Neurapheresis therapy was found to have a greater impact on steady-streaming compared to lumbar drain. Steady-streaming in the cranial SAS was ~ 50× smaller than in the spinal SAS for both cases. CFD results were strongly correlated with the in vitro spatial–temporal tracer concentration under Neurapheresis therapy (R 2 = 0.89 with + 2.13% and − 1.93% tracer concentration confidence interval). Conclusion A subject-specific CFD model of CSF system-wide solute transport was used to investigate the impact of Neurapheresis therapy on tracer removal from CSF compared to lumbar drain over a 24-h period. Neurapheresis therapy was found to substantially increase tracer clearance compared to lumbar drain. The multiphase CFD results were verified by in vitro fluorescein tracer experiments.

中文翻译：

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从脑脊液中去除血液的体外和数值模拟：腰椎引流术与神经分离术治疗的比较

背景 从蛛网膜下腔出血患者的脑脊液 (CSF) 中取出血液可能会降低相关继发性脑损伤的风险。我们制定了一个计算流体动力学 (CFD) 模型，以研究基于双腔导管的 CSF 过滤系统（称为 Neurapheresis™ 疗法）与腰部引流管相比对从 CSF 中去除血液的影响。方法基于MRI测量构建CSF系统范围内溶质运输的特定主题的多相CFD模型。Neurapheresis 导管几何形状被添加到脊髓蛛网膜下腔 (SAS) 内的模型中。Neurapheresis 血流抽吸和回流速率分别为 2.0 和 1.8 mL/min，而腰椎引流的引流率为 0.2 mL/min。血液被建模为 CSF 内的大量流体相，具有 10% 的初始示踪剂浓度和与 CSF 相同的粘度和密度。在模型入口处应用受试者特定的振荡 CSF 流。硬脑膜和脊髓几何结构被认为是静止的。时空示踪剂浓度根据神经分离术治疗和腰椎引流术下整个域的时间平均稳定流动速度进行量化。为了帮助验证 CFD 结果，构建了一个光学透明的体外 CSF 模型，荧光素用作血液替代物。数值和体外结果的定量比较是通过 24 小时内时空示踪剂浓度的线性回归进行的。结果 24 小时后，Neurapheresis 治疗下示踪剂浓度降至 4.9%，而腰椎引流术下为 6.5%。导管抽吸和返回端口之间的示踪剂清除速度最快。与腰椎引流术相比，神经分离术治疗对稳定血流的影响更大。在这两种情况下，颅骨 SAS 中的稳定流比脊柱 SAS 小约 50 倍。CFD 结果与 Neurapheresis 治疗下的体外时空示踪剂浓度密切相关（R 2 = 0.89，示踪剂浓度置信区间为 + 2.13% 和 - 1.93%）。结论 CSF 系统范围内溶质转运的受试者特定 CFD 模型用于研究 Neurapheresis 治疗对 24 小时内与腰椎引流相比从 CSF 中去除示踪剂的影响。与腰椎引流术相比，神经分离术治疗显着增加了示踪剂清除率。多相 CFD 结果通过体外荧光素示踪剂实验验证。在这两种情况下，颅骨 SAS 中的稳定流比脊柱 SAS 小约 50 倍。CFD 结果与 Neurapheresis 治疗下的体外时空示踪剂浓度密切相关（R 2 = 0.89，示踪剂浓度置信区间为 + 2.13% 和 - 1.93%）。结论 CSF 系统范围内的溶质转运的受试者特定 CFD 模型用于研究 Neurapheresis 治疗对 24 小时内与腰椎引流相比从 CSF 中去除示踪剂的影响。与腰椎引流术相比，神经分离术治疗显着增加了示踪剂清除率。多相 CFD 结果通过体外荧光素示踪剂实验得到验证。在这两种情况下，颅骨 SAS 中的稳定流比脊柱 SAS 小约 50 倍。CFD 结果与 Neurapheresis 治疗下的体外时空示踪剂浓度密切相关（R 2 = 0.89，示踪剂浓度置信区间为 + 2.13% 和 - 1.93%）。结论 CSF 系统范围内的溶质转运的受试者特定 CFD 模型用于研究 Neurapheresis 治疗对 24 小时内与腰椎引流相比从 CSF 中去除示踪剂的影响。与腰椎引流术相比，神经分离术治疗显着增加了示踪剂清除率。多相 CFD 结果通过体外荧光素示踪剂实验得到验证。CFD 结果与 Neurapheresis 治疗下的体外时空示踪剂浓度密切相关（R 2 = 0.89，示踪剂浓度置信区间为 + 2.13% 和 - 1.93%）。结论 CSF 系统范围内溶质转运的受试者特定 CFD 模型用于研究 Neurapheresis 治疗对 24 小时内与腰椎引流相比从 CSF 中去除示踪剂的影响。与腰椎引流术相比，神经分离术治疗显着增加了示踪剂清除率。多相 CFD 结果通过体外荧光素示踪剂实验得到验证。CFD 结果与 Neurapheresis 治疗下的体外时空示踪剂浓度密切相关（R 2 = 0.89，示踪剂浓度置信区间为 + 2.13% 和 - 1.93%）。结论 CSF 系统范围内溶质转运的受试者特定 CFD 模型用于研究 Neurapheresis 治疗对 24 小时内与腰椎引流相比从 CSF 中去除示踪剂的影响。与腰椎引流术相比，神经分离术治疗显着增加了示踪剂清除率。多相 CFD 结果通过体外荧光素示踪剂实验验证。结论 CSF 系统范围内溶质转运的受试者特定 CFD 模型用于研究 Neurapheresis 治疗对 24 小时内与腰椎引流相比从 CSF 中去除示踪剂的影响。与腰椎引流术相比，神经分离术治疗显着增加了示踪剂清除率。多相 CFD 结果通过体外荧光素示踪剂实验验证。结论 CSF 系统范围内的溶质转运的受试者特定 CFD 模型用于研究 Neurapheresis 治疗对 24 小时内与腰椎引流相比从 CSF 中去除示踪剂的影响。与腰椎引流术相比，神经分离术治疗显着增加了示踪剂清除率。多相 CFD 结果通过体外荧光素示踪剂实验验证。