Hastings Susan M, Ku David N, Wagoner Scott, Maher Kevin O, Deshpande Shriprasad
From the *GWW School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia; and †Division of Pediatric Cardiology, Children's Healthcare of Atlanta, Emory University, Atlanta, Georgia.
ASAIO J. 2017 Jan/Feb;63(1):86-92. doi: 10.1097/MAT.0000000000000444.
Extracorporeal membrane oxygenation (ECMO) for cardiopulmonary support of critically ill patients is used frequently in the pediatric population. ECMO is burdened by complications, including thrombosis and hemorrhage. Here we demonstrate the focused location of clots, their histologic composition, and the relationship of in situ thrombus to local hemodynamics in ECMO circuits. Pediatric ECMO circuits from Children's Healthcare of Atlanta, Emory University (Atlanta, GA) were obtained after removal from extracorporeal support over a 2.5 year period (n = 50). All clots and material deposited within the circuit were recorded. Location of clot was compared with local hemodynamics. Most clots were adherent to the junctions made by the tubing and connectors, as opposed to being randomly disturbed throughout the circuit tubing (p << 0.05). Loose, nonadherent clots were also found at the entry side of oxygenators. The clots colocated directly with zones of low shear rate. Histology revealed a fibrinous composition, consistent with coagulation potentiated by low shear. Centrifugal pump circuits (n = 16) had more clots than roller pump (n = 34) circuits (p << 0.05). In addition, all centrifugal pumps had clots that formed at the top of the pump shaft. The ECMO circuits from our single-center study demonstrate the concentrated location of fibrin clots at low shear zones created by tubing-connector junctions. Type of pump also influences the frequency of clot formation. Since the mechanism of the majority of ECMO circuit thrombosis is low shear and fibrin driven, optimization of hemodynamics and anticoagulation regimen may reduce clot formation and bleeding.
体外膜肺氧合（ECMO）用于危重症患者的心肺支持，在儿科人群中使用频繁。ECMO存在包括血栓形成和出血在内的并发症。在此，我们展示了血栓的集中位置、组织学组成以及ECMO回路中原位血栓与局部血流动力学的关系。从佐治亚州亚特兰大市埃默里大学儿童医疗保健中心获取了2.5年期间从体外支持移除后的儿科ECMO回路（n = 50）。记录回路内沉积的所有血栓和物质。将血栓位置与局部血流动力学进行比较。大多数血栓附着于管道和连接器形成的连接处，而非随机分布于整个回路管道中（p << 0.05）。在氧合器入口侧也发现了松散的、未附着的血栓。血栓直接与低剪切率区域共定位。组织学显示为纤维蛋白组成，与低剪切增强的凝血一致。离心泵回路（n = 16）比滚压泵回路（n = 34）有更多血栓（p << 0.05）。此外，所有离心泵在泵轴顶部都有血栓形成。我们单中心研究的ECMO回路表明，纤维蛋白血栓集中位于由管道 - 连接器连接处产生的低剪切区域。泵的类型也会影响血栓形成的频率。由于大多数ECMO回路血栓形成的机制是低剪切和纤维蛋白驱动，优化血流动力学和抗凝方案可能会减少血栓形成和出血。
