Wickramarachchi Avishka, Khamooshi Mehrdad, Burrell Aidan, Pellegrino Vincent A, Kaye David M, Gregory Shaun D
Cardio-Respiratory Engineering and Technology Laboratory (CREATElab), Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, VIC, Australia.
Cardio-Respiratory Engineering and Technology Laboratory (CREATElab), Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, VIC, Australia.
Comput Methods Programs Biomed. 2023 Apr;231:107407. doi: 10.1016/j.cmpb.2023.107407. Epub 2023 Feb 6.
Venoarterial extracorporeal membrane oxygenation (VA ECMO) is able to support critically ill patients undergoing refractory cardiopulmonary failure. It relies on drainage cannulae to extract venous blood from the patient, but cannula features and tip position may impact flow dynamics and thrombosis risk. Therefore, this study aimed to investigate the effect of tip position of single-stage (SS) and multi-stage (MS) VA ECMO drainage cannulae on the risk of thrombosis.
Computational fluid dynamics was used to model flow dynamics within patient-specific geometry of the venous vasculature. The tip of the SS and MS cannula was placed in the superior vena cava (SVC), SVC-Right atrium (RA) junction, mid-RA, inferior vena cava (IVC)-RA junction, and IVC. The risk of thrombosis was assessed by measuring several factors. Blood residence time was measured via an Eulerian approach through the use of a scalar source term. Regions of stagnant volume were recognised by identifying regions of low fluid velocity and shear rate. Rate of blood washout was calculated by patching the domain with a scalar value and measuring the rate of fluid displacement. Lastly, wall shear stress values were determined to provide a qualitative understanding of potential blood trauma.
Thrombosis risk varied substantially with position changes of the SS cannula, which was less evident with the MS cannula. The SS cannula showed reduced thrombosis risk arising from stagnant regions when placed in the SVC or SVC-RA junction, whereas an MS cannula was predicted to create stagnant regions during all tip positions. When positioned in the IVC-RA junction or IVC, the risk of thrombosis was higher in the SS cannula than in the MS cannula due to both high and low shear flow.
Tip position of the drainage cannula impacts cannula flow dynamics and, subsequently, the risk of thrombosis. The use of MS cannulae can reduce high shear-related thrombosis, but SS cannulae can eliminate stagnant regions when advanced into the SVC. Therefore, the choice of cannula design and tip position should be carefully considered during cannulation.
静脉 - 动脉体外膜肺氧合（VA ECMO）能够支持患有难治性心肺衰竭的重症患者。它依靠引流插管从患者体内抽取静脉血，但插管的特性和尖端位置可能会影响血流动力学和血栓形成风险。因此，本研究旨在探讨单级（SS）和多级（MS）VA ECMO引流插管的尖端位置对血栓形成风险的影响。
采用计算流体动力学对患者特异性静脉血管几何结构内的血流动力学进行建模。将SS和MS插管的尖端置于上腔静脉（SVC）、SVC - 右心房（RA）交界处、RA中部、下腔静脉（IVC） - RA交界处和IVC。通过测量几个因素来评估血栓形成风险。通过使用标量源项的欧拉方法测量血液停留时间。通过识别低流体速度和剪切速率区域来识别停滞体积区域。通过用标量值修补域并测量流体置换速率来计算血液冲洗速率。最后，确定壁面剪应力值以定性了解潜在的血液损伤。
SS插管的血栓形成风险随位置变化有很大差异，而MS插管则不太明显。当SS插管置于SVC或SVC - RA交界处时，因停滞区域导致的血栓形成风险降低，而预测MS插管在所有尖端位置都会产生停滞区域。当置于IVC - RA交界处或IVC时，由于高剪切流和低剪切流，SS插管的血栓形成风险高于MS插管。
引流插管的尖端位置会影响插管的血流动力学，进而影响血栓形成风险。使用MS插管可降低与高剪切相关的血栓形成，但SS插管推进到SVC时可消除停滞区域。因此，在插管过程中应仔细考虑插管设计和尖端位置的选择。
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