Qiu F, Clark J B, Kunselman A R, Undar A, Myers J L
Pediatric Cardiovascular Research Center, Department of Pediatrics, Milton S. Hershey Medical Center, Penn State Hershey College of Medicine, Hershey, PA 17033, USA.
Perfusion. 2011 Jul;26(4):276-83. doi: 10.1177/0267659111406768. Epub 2011 May 9.
To construct an ideal extracorporeal life support (ECLS) circuit in terms of hemodynamic performance, each component of the circuit should be evaluated. Most cannulae manufacturers evaluate their products using water as the priming solution. We conducted this study to evaluate the different sizes of arterial and venous cannulae in a simulated neonatal ECLS circuit primed with human blood.
The simulated neonatal ECLS circuit was composed of a Capiox Baby RX05 oxygenator, a Rotaflow centrifugal pump and a heater & cooler unit. Three Medtronic Bio-Medicus arterial cannulae (8Fr, 10Fr, 12Fr) and three venous cannulae (10Fr, 12Fr, 14Fr) were tested in seven combinations (8A-10V, 8A-12V, 10A-10V, 10A-12V, 10A-14V, 12A-12V, 12A-14V). All the experiments were conducted using human blood at a hematocrit of 40% and at a constant temperature of 37°C. The "tip to tip" priming volume of the entire circuit was 135ml. The blood volume of the pseudo patient was 500ml.
Flow rates increased linearly with increasing size in both venous and arterial cannulae at the same pump speeds. The increase in flow rate was greater when changing the arterial cannulae (next size larger) compared to changing the venous cannulae (next size larger). The pressure drops of the arterial cannula were correlated with the flow rates, regardless of the pseudo patient pressure and the venous cannula used simultaneously.
The results show the difference in flow ranges and pressure drops of seven combinations of arterial and venous cannulae. It also suggests that the arterial cannula, not the venous cannula, has greater impact on the flow rate when a centrifugal pump is used in a neonatal ECLS circuit. The results of this study have been translated to further advancing the clinical practice in our institution.
为构建一个在血流动力学性能方面理想的体外生命支持（ECLS）回路，应对回路的每个组件进行评估。大多数插管制造商使用水作为预充溶液来评估其产品。我们开展本研究以评估在用人血预充的模拟新生儿ECLS回路中不同尺寸的动脉和静脉插管。
模拟新生儿ECLS回路由一个Capiox Baby RX05氧合器、一个Rotaflow离心泵和一个加热及冷却单元组成。对三根美敦力Bio-Medicus动脉插管（8Fr、10Fr、12Fr）和三根静脉插管（10Fr、12Fr、14Fr）进行了七种组合测试（8A - 10V、8A - 12V、10A - 10V、10A - 12V、10A - 14V、12A - 12V、12A - 14V）。所有实验均使用血细胞比容为40%的人血，且在37°C恒温下进行。整个回路的“尖端到尖端”预充量为135ml。虚拟患者的血容量为500ml。
在相同泵速下，静脉和动脉插管的流速均随尺寸增大呈线性增加。与更换静脉插管（增大一个尺寸）相比，更换动脉插管（增大一个尺寸）时流速增加幅度更大。动脉插管的压力降与流速相关，与虚拟患者压力及同时使用的静脉插管无关。
结果显示了动脉和静脉插管七种组合在流速范围和压力降方面的差异。这也表明在新生儿ECLS回路中使用离心泵时，对流速影响更大的是动脉插管而非静脉插管。本研究结果已转化为推动我们机构临床实践的进一步发展。
