V-A ECMO的不同血流量对主动脉血流分布的数值研究

Numerical analysis of aortic blood flow distribution with different V-A ECMO blood flow

目的不同血流量的动静脉体外膜肺氧合(veno-arterial extracorporeal membrane oxygenation,V-A ECMO)对心脏、脑、肾脏和下肢血流灌注的血流动力学影响尚存在争议。本文采用数值模拟的方法研究V-A ECMO不同血流量对主动脉血流分布的影响。方法基于患者CT图像数据,采用MIMICS软件重建主动脉和ECMO插管模型,随后进行网格划分和边界条件设定,通过Adina软件进行流固耦合计算,分析心衰(heart failure,HF)、ECMO辅助1.0 L、1.5 L、2.0 L、2.5 L、3.0 L的血流动力学变化,研究体外膜肺氧合的效果。结果ECMO辅助后,增加了脑部、肾脏和下肢血流。随着ECMO血流量增加,血液交汇面向主动脉弓移动。与其他辅助情况相比较,ECMO 3.0 L时头臂干血流量减少(HF vs.ECMO 1.0 L vs.ECMO 1.5 L vs.ECMO 2.0 L vs.ECMO 2.5 L vs.ECMO 3.0 L:1339.3 mL/min vs.1851.49 mL/min vs.2027.26 mL/min vs.2332.07 mL/min vs.2611.04 mL/min vs.1792.64 mL/min)。ECMO插管侧即右侧股动脉血流明显减小,且随ECMO血流量增大整体呈现先减小后增加的趋势,而左侧股动脉血流量随ECMO血流量增加呈平缓增大的趋势,两侧股动脉血流量最大相差5.9倍(ECMO 2.0 L:186.90 mL/min vs.1102.59 mL/min)。ECMO辅助后,降低了主动脉弓血流速度。高血管壁应力集中在主动脉内侧和头臂干根部。ECMO辅助后血管壁应力发生改变,在血流量最大时刻(1.696 s),最大应力逐渐增加(0.60 MPa vs.0.61 MPa vs.0.62 MPa vs.0.63 MPa vs.0.64 MPa)。结论V-A ECMO增加血液灌注,但血液交汇面对于脑血流量的影响值得关注。

Objective The hemodynamic effects of veno-arterial extracorporeal pulmonary oxygenation(V-A ECMO)with different blood flow on heart,brain,kidney,and lower limb blood perfusion are controversial.In view of this problem,this paper uses numerical simulation to study the influence of V-A ECMO under different blood flow on the aortic blood flow distribution.Methods A three-dimensional reconstruction by MIMICS according to the CT image data of the patient was used to establish a finite element model of the aorta and ECMO.Then,the boundary conditions were set,Adina software was used to calculate hemodynamic changes of heart failure and ECMO-assisted 1.0 L,1.5 L,2.0 L,2.5 L,and 3.0 L through fluid-solid coupling method to study the effect of extracorporeal membrane oxygenation.Results ECMO increased blood flow to the brain,kidneys and lower limbs.As ECMO blood flow increased,the blood confluence moved toward the aortic arch.Compared with other auxiliary cases,the blood flow of brachiocephalic trunk decreased obviously during ECMO 3.0 L(HF vs.ECMO 1.0 L vs.ECMO 1.5 L vs.ECMO 2.0 L vs.ECMO 2.5 L vs.ECMO 3.0 L:1339.3 mL/min vs.1851.49 mL/min vs.2027.26 mL/min vs.2332.07 mL/min vs.2611.04 mL/min vs.1792.64 mL/min).On the side of ECMO intubation,the right femoral arterial blood flow was significantly reduced,and as the ECMO blood flow increased,it showed a trend of first decrease and then increase,while the left femoral arterial blood flow increased gradually with the ECMO blood flow increase trend,the maximum difference in femoral artery blood flow on both sides was 5.9 times(ECMO 2.0 L:186.90 mL/min vs.1102.59 mL/min).After the ECMO adjuvant therapy,blood flow velocity of aortic arch decreased and high blood vessel wall stress built up at the inside of the aorta and the roots of the brachiocephalic trunk.After ECMO assisted,the blood vessel wall stress changed.At the time of maximum blood flow(1.696 s),the maximum stress gradually increased(0.60 MPa vs.0.61 MPa vs.0.62 MPa vs.0.63 MPa vs.0.64 MPa).Conclusions V-A ECMO increases blood perfusion,yet the effect of blood junctions on cerebral blood flow is worthy of attention.