Callaham M, Madsen C D
Division of Emergency Medicine, University of California, San Francisco, USA.
Ann Emerg Med. 1996 May;27(5):638-48. doi: 10.1016/s0196-0644(96)70169-5.
We sought to determine whether the interval between the arrival of first responder/defibrillators and paramedic advanced life support (ALS) interventions is associated with outcome.
We carried out a prospective observational study of adults in out-of-hospital cardiac arrest treated by both first responders and paramedics in an urban emergency medical services system between July 15, 1992, and May 27, 1993 (N = 544).
The gap between first-responder and medic arrival was short (3.2 minutes); medics arrived before first-responder shock in 22% of ventricular fibrillation (VF) cases. Just 10% of patients has a pulse when medics arrived, but the presence of pulse on medic arrival was a powerful predictor of hospital discharge (odds ratio [OR], 20.5; sensitivity, 39%; specificity, 98%; positive predictive value, 55%; negative predictive value, 97%) or a Cerebral Performance Category score on discharge of 1 or 2 (OR, 2.9). No response or individual ALS treatment interval was related to outcome, including the interval from first-responder to medic arrival. ALS interventions by medics were associated with poorer outcomes; even the need for nothing more than additional defibrillation by medics decreased the survival rate of VF patients threefold. By contrast, bystander CPR improved survival more than fourfold and early defibrillation of VF by first responders more than ninefold. Ninety-one percent of all patients discharged from the hospital who received only minimal ALS other than intubation had good neurologic outcome and longer survival after discharge. Half the total survivors of VF arrest (and 59% of all arrest survivors) were resuscitated by medics with aggressive ALS measures, but 80% had very poor neurologic outcomes and 50% died within a year of hospital discharge. Even the need for only additional defibrillation by medics worsened neurologic outcome by a factor of 2.8.
Faster response by medics, or any individual ALS intervention other than first-responder defibrillation, demonstrated no benefit in this urban population with short intervals between responder arrivals. Aggressive ALS increased the number of survivors but also decreased their neurologic quality. The benefit of rapid ALS backup to first responder/defibrillators needs further study in other systems. System performance cannot be judged without knowledge of neurologic outcome.
我们试图确定第一反应者/除颤器到达与护理人员高级生命支持（ALS）干预之间的间隔时间是否与预后相关。
我们对1992年7月15日至1993年5月27日期间在城市紧急医疗服务系统中接受第一反应者和护理人员治疗的院外心脏骤停成人进行了一项前瞻性观察研究（N = 544）。
第一反应者和护理人员到达之间的间隔时间很短（3.2分钟）；在22%的心室颤动（VF）病例中，护理人员在第一反应者电击之前到达。护理人员到达时只有10%的患者有脉搏，但护理人员到达时存在脉搏是出院的有力预测因素（优势比[OR]，20.5；敏感性，39%；特异性，98%；阳性预测值，55%；阴性预测值，97%）或出院时脑功能分类评分为1或2（OR，2.9）。无反应或任何个体ALS治疗间隔与预后无关，包括从第一反应者到护理人员到达的间隔时间。护理人员的ALS干预与较差的预后相关；即使护理人员只需要额外除颤也会使VF患者的存活率降低三倍。相比之下，旁观者心肺复苏使存活率提高了四倍多，第一反应者对VF的早期除颤使存活率提高了九倍多。所有出院的患者中，除插管外仅接受极少ALS治疗的患者中有91%具有良好的神经学预后且出院后存活时间更长。VF心脏骤停的幸存者中有一半（所有心脏骤停幸存者的59%）是由护理人员采用积极的ALS措施复苏的，但80%的患者神经学预后很差，50%的患者在出院后一年内死亡。即使护理人员只需要额外除颤也会使神经学预后恶化2.8倍。
在这个反应者到达间隔时间短的城市人群中，护理人员更快的反应或除第一反应者除颤外的任何个体ALS干预均未显示出益处。积极的ALS增加了幸存者数量，但也降低了他们的神经学质量。第一反应者/除颤器快速ALS支援的益处需要在其他系统中进一步研究。如果不了解神经学预后，就无法判断系统性能。
