Ferrari Lorenzo, Bartkevics Maris, Jenni Hansjörg, Kadner Alexander, Siepe Matthias, Obrist Dominik
ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland.
Department of Cardiac Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
Artif Organs. 2025 Mar;49(3):420-430. doi: 10.1111/aor.14897. Epub 2024 Oct 28.
This study evaluated the hemodynamic performance of arterial and venous cannulae in a compliant pediatric extracorporeal membrane oxygenation (ECMO) mock circuit in pulsatile and non-pulsatile flow conditions.
The ECMO setup consisted of an oxygenator, diagonal pump, and standardized-length arterial/venous tubing with pressure transducers. A validated left-heart mock loop was adapted to simulate pediatric conditions. The pulsatile flow was driven by a computer-controlled piston pump set at 120 bpm. A roller pump was used for non-pulsatile conditions. The circuit was primed with 40% glycerol-based solution. The cardiac output was set to 1 L/min and the aortic pressure to 40-50 mmHg. Four arterial cannulae (8Fr, 10Fr, 12Fr, 14Fr) and five venous cannulae (12Fr, 14Fr, 16Fr, 18Fr, 20Fr) (Medtronic, Inc., Minneapolis, MN, USA) were tested at increasing flow rate in 12 combinations.
The pulsatile condition required lower ECMO pump speeds for all cannulae combinations at a given flow rate, inducing a significantly smaller increase of flow in the mock loop. Under non-pulsatile conditions, the aortic and arterial pressures in the cannulae were higher (p < 0.01) while no significant differences in pressure drop and pressure-flow characteristics (M-number) were observed. The total hemodynamic energy was higher in case of non-pulsatile flow (p < 0.01).
Under non-pulsatile conditions, the system was characterized by overall higher pressures, resulting in higher support to the patient. The consequent increase of potential energy compensates for increases of kinetic energy, leading to a higher total hemodynamic energy. Pressure gradients and M number are independent of the testing conditions. Pulsatile testing conditions led to more physiological testing conditions, and it is recommended for ECMO testing.
本研究评估了在顺应性小儿体外膜肺氧合（ECMO）模拟回路中，在搏动性和非搏动性血流条件下动脉和静脉插管的血流动力学性能。
ECMO装置包括一个氧合器、对角泵以及带有压力传感器的标准化长度的动脉/静脉管道。采用经过验证的左心模拟回路来模拟小儿情况。搏动性血流由设置为120次/分钟的计算机控制活塞泵驱动。非搏动性条件下使用滚压泵。回路用40%甘油基溶液预充。心输出量设定为1升/分钟，主动脉压力设定为40 - 50毫米汞柱。对四根动脉插管（8Fr、10Fr、12Fr、14Fr）和五根静脉插管（12Fr、14Fr、16Fr、18Fr、20Fr）（美敦力公司，明尼阿波利斯，明尼苏达州，美国）以12种组合在逐渐增加的流速下进行测试。
在给定流速下，对于所有插管组合，搏动性条件下所需的ECMO泵速较低，在模拟回路中引起的流量增加明显较小。在非搏动性条件下，插管内的主动脉和动脉压力较高（p < 0.01），而在压降和压力 - 流量特性（M数）方面未观察到显著差异。非搏动性血流情况下总的血流动力学能量较高（p < 0.01）。
在非搏动性条件下，该系统的特点是总体压力较高，对患者的支持力度更大。势能的相应增加补偿了动能的增加，导致总的血流动力学能量更高。压力梯度和M数与测试条件无关。搏动性测试条件导致更符合生理的测试条件，推荐用于ECMO测试。
