School of Mechanical, Medical and Process Engineering, Faculty of Engineering, Queensland University of Technology (QUT), Brisbane, QLD, Australia.
Innovative Cardiovascular Engineering and Technology Laboratory (ICETLAB), Critical Care Research Group, The Prince Charles Hospital, Brisbane, QLD, Australia.
Perfusion. 2023 Sep;38(6):1213-1221. doi: 10.1177/02676591221108810. Epub 2022 Jun 15.
Trendelenburg position (TP) is used to transport gaseous emboli away from the cerebral region during cardiac surgery. However, TP effectiveness has not been fully considered when combined with varying the cardiopulmonary bypass (CPB) flow. This study simulated the supine and TP at different pump flows and assessed the trapped emboli and embolic load entering the aortic arch branch arteries (AABA).
A computational fluid dynamics (CFD) approach used a centrally cannulated adult patient-specific aorta model replicating a CPB circuit. Air emboli of 0.1 mm, 0.5 mm, and 1.0 mm ( = 700 each) were injected into the aorta placed in the supine position (0°) and the TP (-20°) at 2 L/min and 5 L/min. The number of emboli entering the AABA were compared. An aortic phantom flow experiment was performed to validate air bubble behaviour.
TP at 5 L/min had the lowest 0.1 mm mean (±SD) embolic load compared to the supine 2 L/min (55.3 ± 30.8 vs 64.3 ± 35.4). For both the supine and TP, the lower flow of 2 L/min had the highest number of simulated trapped emboli in higher elevated regions than at 5 L/min (541 ± 185 and 548 ± 191 vs 520 ± 159 and 512 ± 174), respectively. The flow experiment demonstrated that 2 L/min promoted bubble coalescence and high amounts of trapped emboli and 5 L/min transported air emboli away from the AABA.
TP effectiveness was improved by using CPB flow to manage air emboli. These results provide insights for predicting emboli behaviour and improving emboli de-airing procedures.
在心脏手术中，特伦德伦堡体位（TP）用于将气态栓子从脑部区域运走。然而，当与改变心肺转流（CPB）流量结合使用时，TP 的效果并未得到充分考虑。本研究在不同泵流量下模拟了仰卧位和 TP，并评估了进入主动脉弓分支动脉（AABA）的被困栓子和栓子负荷。
使用一种计算流体动力学（CFD）方法，通过模拟 CPB 回路的中心插管成人患者特定的主动脉模型来进行。将 0.1mm、0.5mm 和 1.0mm 的空气栓子（各 700 个）注入放置在仰卧位（0°）和 TP（-20°）的主动脉中，流量分别为 2L/min 和 5L/min。比较进入 AABA 的栓子数量。进行了主动脉幻影流量实验以验证空气泡行为。
与仰卧位 2L/min 相比，5L/min 下 TP 的 0.1mm 平均（±SD）栓子负荷最低（55.3 ± 30.8 比 64.3 ± 35.4）。对于仰卧位和 TP，较低的 2L/min 流量在较高的升高区域中产生的模拟被困栓子数量比 5L/min 多（541 ± 185 和 548 ± 191 比 520 ± 159 和 512 ± 174）。流量实验表明，2L/min 促进了气泡聚结以及大量被困栓子的产生，而 5L/min 则将空气栓子从 AABA 运走。
通过使用 CPB 流量来管理空气栓子，提高了 TP 的效果。这些结果为预测栓子行为和改进栓子除气程序提供了参考。
