From the Seattle Children's Hospital, Seattle, Washington.
Division of Cardiothoracic Surgery, Department of Surgery, University of Washington, Seattle, Washington.
ASAIO J. 2022 Aug 1;68(8):1083-1092. doi: 10.1097/MAT.0000000000001605. Epub 2021 Dec 1.
Thrombosis in extracorporeal membrane oxygenation (ECMO) circuits remains a frequent complication. We characterize the location, extent, structure, and clinical implications of thrombi in 53 ECMO circuits from 46 pediatric patients. The tubing, pump, and oxygenator were examined for visible thrombi. Representative samples of thrombi were collected for histologic, immunofluorescence, and immunohistochemical analysis. Thrombi were found in 81% of ECMO circuits. The most clinically significant were inflow oxygenator membrane surface thrombi (11% of circuits), arterial tubing thrombi (30%), and venous tubing (26%) or connector thrombi (26%). Oxygenator membrane surface thrombi resulted in rapidly increasing delta pressure across the oxygenator over 1-2 days, oxygenator failure, and circuit replacement. Oxygenator membrane surface thrombi were associated with intravascular venous thrombosis and bacterial infection before starting ECMO. Arterial cannula/tubing thrombi led in one case to aortic and mesenteric artery thrombosis followed by bowel infarction. In 11% of cases, venous tubing thrombi grew large enough to break off and embolize to the pump, resulting in increased hemolysis. Antifibrinolytic therapy during ECMO was associated with an increased risk of pump thromboembolism. Other less clinically significant thrombi included pump axle thrombi with thrombus fragments trapped in the oxygenator (45%), and deep oxygenator membrane thrombi (15%). Examination of ECMO circuits after removal is a useful quality improvement tool that can elucidate the cause of circuit problems, indicate patients at increased risk of thrombosis, and suggest areas for possible improvements.
体外膜肺氧合（ECMO）回路中的血栓仍然是一种常见的并发症。我们对 46 名儿科患者的 53 个 ECMO 回路中的血栓的位置、程度、结构和临床意义进行了描述。对管道、泵和氧合器进行了可见血栓的检查。收集了血栓的代表性样本，用于组织学、免疫荧光和免疫组织化学分析。在 81%的 ECMO 回路中发现了血栓。最具临床意义的是流入氧合器膜表面血栓（占回路的 11%）、动脉管道血栓（30%）、静脉管道（26%）或连接器血栓（26%）。氧合器膜表面血栓会导致氧合器的 delta 压力在 1-2 天内迅速增加，导致氧合器失效和回路更换。氧合器膜表面血栓与开始 ECMO 前的血管内静脉血栓形成和细菌感染有关。动脉插管/管道血栓导致 1 例主动脉和肠系膜动脉血栓形成，随后发生肠梗死。在 11%的情况下，静脉管道血栓长得足够大，脱落并栓塞到泵中，导致溶血增加。ECMO 期间使用抗纤维蛋白溶解治疗与泵血栓栓塞的风险增加有关。其他不太具临床意义的血栓包括泵轴血栓，血栓碎片被困在氧合器中（占 45%），以及深部氧合器膜血栓（占 15%）。在移除后检查 ECMO 回路是一种有用的质量改进工具，可以阐明回路问题的原因，指示血栓形成风险增加的患者，并提出可能改进的领域。
