Division of Prehospital Care, Sunnybrook Health Science Centre, University of Toronto, Toronto, Ontario, Canada.
Prehosp Emerg Care. 2012 Jan-Mar;16(1):109-14. doi: 10.3109/10903127.2011.614045. Epub 2011 Sep 28.
Many prehospital protocols require acquisition of a single 12-lead electrocardiogram (ECG) when assessing a patient for ST-segment elevation myocardial infarction (STEMI). However, it is known that ECG evidence of STEMI can evolve over time.
To determine how often the first and, if necessary, second or third prehospital ECGs identified STEMI, and the time intervals associated with acquiring these ECGs and arrival at the emergency department (ED).
We retrospectively analyzed 325 consecutive prehospital STEMIs identified between June 2008 and May 2009 in a large third-service emergency medical services (EMS) system. If the first ECG did not identify STEMI, protocol required a second ECG just before transport and, if necessary, a third ECG before entering the receiving ED. Paramedics who identified STEMI at any time bypassed participating local EDs, taking patients directly to the percutaneous coronary intervention (PCI) center. Paramedics used computerized ECG interpretation with STEMI diagnosis defined as an "acute MI" report by GE/Marquette 12-SL software in ZOLL E-series defibrillator/cardiac monitors (ZOLL Medical, Chelmsford, MA). We recorded the time of each ECG, and the ordinal number of the diagnostic ECG. We then determined the number of cases and frequency of STEMI diagnosis on the first, second, or third ECG. We also measured the interval between ECGs and the interval from the initial positive ECG to arrival at the ED. Results. STEMI was identified on the first prehospital ECG in 275 cases, on the second ECG in 30 cases, and on the third ECG in 20 cases (cumulative percentages of 84.6%, 93.8%, and 100%, respectively). For STEMIs identified on the second or third ECG, 90% were identified within 25 minutes after the first ECG. The median times from identification of STEMI to arrival at the ED were 17.5 minutes, 11.0 minutes, and 0.7 minutes for STEMIs identified on the first, second, and third ECGs, respectively.
A single prehospital ECG would have identified only 84.6% of STEMI patients. This suggests caution using a single prehospital ECG to rule out STEMI. Three serial ECGs acquired over 25 minutes is feasible and may be valuable in maximizing prehospital diagnostic yield, particularly where emergent access to PCI exists.
许多院前协议要求在评估 ST 段抬高型心肌梗死 (STEMI) 患者时获取单份 12 导联心电图 (ECG)。然而，已知 STEMI 的 ECG 证据会随时间演变。
确定首次和（如有必要）第二次或第三次院前 ECG 识别 STEMI 的频率，以及获取这些 ECG 的时间间隔和到达急诊部 (ED) 的时间间隔。
我们回顾性分析了 2008 年 6 月至 2009 年 5 月期间在一个大型第三方紧急医疗服务 (EMS) 系统中确定的 325 例连续院前 STEMI。如果首次 ECG 未识别出 STEMI，则协议要求在转运前进行第二次 ECG，如果有必要，在进入接收 ED 前进行第三次 ECG。任何时候识别出 STEMI 的护理人员都会绕过参与的当地 ED，直接将患者送往经皮冠状动脉介入治疗 (PCI) 中心。护理人员使用计算机化 ECG 解读，GE/Marquette 12-SL 软件通过 ZOLL E 系列除颤器/心脏监护仪 (ZOLL Medical，Chelmsford，MA) 诊断为“急性 MI”的报告定义为 STEMI。我们记录了每次 ECG 的时间，以及诊断 ECG 的序号。然后，我们确定了首次、第二次或第三次 ECG 上 STEMI 诊断的病例数和频率。我们还测量了 ECG 之间的间隔以及从首次阳性 ECG 到到达 ED 的间隔。结果：首次院前 ECG 识别出 275 例 STEMI，第二次 ECG 识别出 30 例，第三次 ECG 识别出 20 例（分别占 84.6%、93.8%和 100%的累积百分比）。对于第二次或第三次 ECG 识别出的 STEMI，90%在首次 ECG 后 25 分钟内识别出。首次、第二次和第三次 ECG 识别出的 STEMI 到达 ED 的中位时间分别为 17.5 分钟、11.0 分钟和 0.7 分钟。
单次院前 ECG 仅能识别 84.6%的 STEMI 患者。这表明在排除 STEMI 时使用单次院前 ECG 应谨慎。在 25 分钟内获取三个连续 ECG 是可行的，并且可能有助于最大限度地提高院前诊断效果，特别是在存在紧急 PCI 时。
