Extracorporeal membrane oxygenation use in poisoning: a narrative review with clinical recommendations

Poisoning may lead to respiratory failure, shock, cardiac arrest, or death. Extracorporeal membrane oxygenation (ECMO) may be used to provide circulatory support, termed venoarterial (VA) ECMO; or respiratory support termed venovenous (VV) ECMO. The clinical utility of ECMO in poisoned patients remains unclear and guidelines on its use in this setting are lacking. To perform a literature search and narrative review on the use of ECMO in poisonings. Additionally, to provide recommendations on the use of ECMO in poisonings from physicians with expertise in ECMO, medical toxicology, critical care, and emergency medicine. A literature search in Ovid MEDLINE from 1946 to October 14, 2020, was performed to identify relevant articles with a strategy utilizing both MeSH terms and adjacency searching that encompassed both extracorporeal life support/ECMO/Membrane Oxygenation concepts and chemically-induced disorders/toxicity/poisoning concepts, which identified 318 unique records. Twelve additional manuscripts were identified by the authors for a total of 330 articles for screening, of which 156 were included for this report. The use of ECMO in poisoned patients is significantly increasing over time. Available retrospective data suggest that patients receiving VA ECMO for refractory shock or cardiac arrest due to poisoning have lower mortality as compared to those who receive VA ECMO for non-poisoning-related indications. Poisoned patients treated with ECMO have reduced mortality as compared to those treated without ECMO with similar severity of illness and after adjusted analyses, regardless of the type of ingestion. This is especially evident for poisoned patients with refractory cardiac arrest placed on VA ECMO (termed extracorporeal cardiopulmonary resuscitation [ECPR]). We suggest VA ECMO be considered for poisoned patients with refractory cardiogenic shock (continued shock with myocardial dysfunction despite fluid resuscitation, vasoactive support, and indicated toxicologic therapies such as glucagon, intravenous lipid emulsion, hyperinsulinemia euglycemia therapy, or others), and strongly considered for patients with cardiac arrest in institutions which are structured to deliver effective ECPR. VV ECMO should be considered in poisoned patients with ARDS or severe respiratory failure according to traditional indications for ECMO in this setting. Patients with pre-existing comorbidities with low expected survival or recovery. Relative contraindications vary based on each center’s experience but often include: severe brain injury; advanced age; unrepaired aortic dissection or severe aortic regurgitation in VA ECMO; irreversible organ injury; contraindication to systemic anticoagulation, such as severe hemorrhage. ECMO may provide hemodynamic or respiratory support to poisoned patients while they recover from the toxic exposure and metabolize or eliminate the toxic agent. Available literature suggests a potential benefit for ECMO use in selected poisoned patients with refractory shock, cardiac arrest, or respiratory failure. Future studies may help to further our understanding of the use and complications of ECMO in poisoned patients.

中毒可引发呼吸衰竭、休克、心搏骤停甚至死亡。体外膜肺氧合（Extracorporeal membrane oxygenation, ECMO）可用于提供循环支持，此类模式被称为静脉-动脉（venoarterial, VA）ECMO；亦可用于呼吸支持，对应模式为静脉-静脉（venovenous, VV）ECMO。目前，ECMO在中毒患者中的临床应用价值仍不明确，且缺乏针对该场景下ECMO使用的相关指南。本研究旨在针对ECMO在中毒救治中的应用开展文献检索与叙述性综述；此外，由具备ECMO、医学毒理学、重症医学及急诊医学专长的医师团队，提出中毒患者ECMO使用的相关推荐意见。本研究于2020年10月14日前，对1946年起的Ovid MEDLINE数据库开展文献检索：检索策略结合医学主题词（Medical Subject Headings, MeSH）与邻近词检索，覆盖体外生命支持/ECMO/膜氧合相关概念，以及化学诱导性疾病/中毒相关概念，最终筛选得到318条独立文献记录。研究团队额外补充检索到12篇文献，最终纳入待筛查的文献共计330篇，其中156篇被纳入本综述报告。中毒患者使用ECMO的比例随时间推移显著上升。现有回顾性研究数据显示，因中毒导致难治性休克或心搏骤停而接受VA ECMO的患者，其死亡率低于因非中毒相关适应证接受VA ECMO的患者。经校正混杂因素分析后可见，无论中毒途径为何，病情严重程度匹配的中毒患者中，接受ECMO治疗者的死亡率显著低于未接受ECMO治疗者。对于接受VA ECMO（即体外心肺复苏术，extracorporeal cardiopulmonary resuscitation, ECPR）治疗的难治性心搏骤停中毒患者，这一差异尤为显著。我们建议，对于出现难治性心源性休克的中毒患者，即经液体复苏、血管活性药物支持及指南推荐的毒理学治疗如胰高血糖素、静脉脂肪乳剂、高胰岛素血症正常血糖治疗等后仍持续存在休克伴心肌功能障碍的患者，可考虑使用VA ECMO；对于具备有效开展ECPR条件的医疗机构中的心搏骤停中毒患者，则应强烈推荐使用VA ECMO。对于出现急性呼吸窘迫综合征（Acute Respiratory Distress Syndrome, ARDS）或重度呼吸衰竭的中毒患者，可参照该场景下ECMO的传统适应证，考虑使用VV ECMO。对于存在基础合并症且预期生存或康复可能性较低的患者，需审慎评估其ECMO使用指征。相对禁忌证因各中心的临床经验不同而存在差异，通常包括：重度脑损伤、高龄、未修复的主动脉夹层或VA ECMO术中的重度主动脉瓣反流、不可逆器官损伤、全身性抗凝禁忌如重度出血。ECMO可为中毒患者提供血流动力学或呼吸支持，帮助其完成毒物暴露后的恢复过程，并代谢或清除体内毒物。现有文献表明，对于经筛选的出现难治性休克、心搏骤停或呼吸衰竭的中毒患者，使用ECMO可能带来临床获益。未来的研究将有助于进一步明确ECMO在中毒患者中的应用价值及其相关并发症。