VA ECMOを導入した重度低温曝露性低体温症における多様な心電図変化と神経学的転帰(Various electrocardiogram changes and neurological outcome in patients with severe cold–exposure hypothermia treated with veno–arterial extracorporeal membrane oxygenation)

要旨 【目的】体温28℃以下の重度偶発性低体温症は心停止で発見されることも多く，多彩な心電図波形変化を来すとともに搬送中に心停止に移行する救助時虚脱（rescue collapse）も発生しうる。これらの心電図波形変化とVA ECMO治療による転帰について検討した。【対象】2001年2月～2017年1月にVA ECMOを導入した低温曝露性低体温症34例を対象とし，低温曝露場所，初期心電図波形，rescue collapseの発生，搬入時体温，転帰を後方視的に調査した。【結果】34例中2例はbradycardiaの循環不安定であり，23例が心停止で発見され，rescue collapseを9例に認めた。VA ECMO離脱79%，生存68%，神経学的転帰良好59%で，rescue collapseの78%が神経学的転帰良好であった。発見時心停止症例の初期心電図波形別の神経学的転帰良好率はそれぞれVF 57%，PEA 100%，心静止 25%であった。【結語】重度低温曝露性低体温症ではrescue collapseを含め，多彩な心電図波形変化を呈するが，心電図波形がPEAや心静止でもVA ECMOを用いて救命されることも多い。rescue collapseを起こしうることを念頭において搬送し，低体温であることを意識した，平温時の心電図評価とは異なる視点での治療が必要と考えられた。 ABSTRACT Objective: In cardiac arrest, severe accidental hypothermia with a body temperature below 28℃ is frequently observed, resulting in various ECG waveform abnormalities and rescue collapse and leading to cardiac arrest during transport. We investigated these ECG changes and the outcome of VA ECMO treatment. Subjects: We retrospectively investigated the location of cold exposure, initial ECG waveform, occurrence of rescue collapse, temperature during delivery, and prognosis of cold–exposed hypothermia in 34 patients treated with VA ECMO between February 2001 and January 2017. Result: Two of the 34 patients were circulatory unstable with bradycardia, 23 patients were discovered to be in cardiac arrest, and 9 patients had cardiac arrest due to rescue collapse. VA ECMO withdrawal was 79%, 68% survival, and 59% good neurologic outcome; 78% of cardiac arrests caused by rescue collapse had a favorable neurologic outcome. According to the first ECG waveform, the excellent neurological outcome rates were VF: 57%, PEA: 100%, and asystole: 25%, respectively. Conclusion: Patients suffering from severe cold exposure hypothermia had various ECG changes, including “rescue collapse”, and were frequently saved in cases of PEA and asystole of initial ECG. Therefore, it is imperative to understand hypothermia and “rescue collapse” at the scene, and carefully transfer patients. Furthermore, we must treat cardiac arrest from various perspectives, including ECG evaluation at normal temperature.