Cone David C, Galante Nicholas, MacMillan Donald S
Division of EMS, Section of Emergency Medicine, Yale University School of Medicine, New Haven, Connecticut 06519-1315, USA.
Prehosp Emerg Care. 2008 Oct-Dec;12(4):479-85. doi: 10.1080/10903120802290844.
Emergency medical dispatch (EMD) protocols are intended to match response resources with patient needs. In a small city that previously sent a first-responder basic life support (BLS) engine company lights-and-siren response to every emergency medical services (EMS) call, regardless of nature or severity, an EMD system was implemented in order to reduce the number of such responses. The study objectives were to determine the effects of the EMD system on first-responder call volume and to assess the safety of the system.
This was a prospective, before-after trial. Using computer-assisted dispatch (CAD) records, all EMS calls in the 120 days before implementation of the EMD protocol and the 120 days after implementation were identified (excluding a one-month wash-in period). In the "after" phase, patient care reports of a random sample of cases in which an ambulance was dispatched with no first responders was manually reviewed to assess whether there might have been any benefit to first-responder dispatch. Given the lack of accepted clinical criteria for need for first responders, the investigators' clinical judgment was used. Paired t-tests were used to compare groups.
There were 9,820 EMS calls in the "before" phase, with 8,278 first-responder engine runs (84.3%), and 9,943 EMS calls in the "after" phase, with 3,804 first-responder engine runs (39.1%). The first-responder companies were dispatched to a median of 5.65 runs/day (range 1.1-12.7) in the "before" phase, and 3.17 runs/day (range 0.6-5.0) in the "after" phase (p = 0.0008 by paired t-test). Review of 1,816 "after" phase ambulance-only patient care reports (PCRs) found ten (0.55%) in which first-responder dispatch might have been beneficial, but review of EMS and emergency department (ED) records found no adverse outcomes in these ten patients.
This study suggests that a formal EMD system can reduce first-responder call volume by roughly one-half. The system appears to be safe for patients, with an undertriage rate of about one-half of one percent.
紧急医疗调度（EMD）协议旨在使响应资源与患者需求相匹配。在一个小城市中，此前无论紧急医疗服务（EMS）呼叫的性质或严重程度如何，都会派出急救基本生命支持（BLS）引擎公司鸣笛出诊，为了减少此类出诊次数，实施了一个EMD系统。研究目的是确定EMD系统对急救人员出诊量的影响，并评估该系统的安全性。
这是一项前瞻性的前后对照试验。利用计算机辅助调度（CAD）记录，确定在实施EMD协议前120天和实施后120天内的所有EMS呼叫（不包括一个月的磨合期）。在“实施后”阶段，人工审查了随机抽取的未派出急救人员但派出救护车的病例的患者护理报告，以评估派出急救人员是否可能有任何益处。由于缺乏关于是否需要急救人员的公认临床标准，采用了研究人员的临床判断。使用配对t检验比较各组。
“实施前”阶段有9820次EMS呼叫，其中8278次派出了急救人员引擎出诊（84.3%），“实施后”阶段有9943次EMS呼叫，其中3804次派出了急救人员引擎出诊（39.1%）。急救人员公司在“实施前”阶段的出诊中位数为每天5.65次（范围1.1 - 12.7次），在“实施后”阶段为每天3.17次（范围0.6 - 5.0次）（配对t检验p = 0.0008）。审查了1816份“实施后”阶段仅派出救护车的患者护理报告（PCR），发现其中10份（0.55%）派出急救人员可能有益，但审查EMS和急诊科（ED）记录发现这10名患者没有不良后果。
本研究表明，正式的EMD系统可将急救人员出诊量减少约一半。该系统对患者似乎是安全的，漏诊率约为0.5%。
