Sporer Karl A, Johnson Nicholas J, Yeh Clement C, Youngblood Glen M
Department of Emergency Medicine, University of California, San Francisco, California, USA.
Prehosp Emerg Care. 2008 Oct-Dec;12(4):470-8. doi: 10.1080/10903120802290877.
The Medical Priority Dispatch System is an emergency medical dispatch (EMD) system that is widely used to categorize 9-1-1 calls and optimize resource allocation. This study evaluates the ability of EMD and non-EMD codes (calls not processed by EMD) to predict prehospital use of medications and procedures.
All transported prehospital patients placed in an EMD or non-EMD category that exceeded 500 total calls from January 1, 2004, to December 31, 2006, in a suburban California county were matched with their prehospital electronic patient care record. These records (N = 69,541) were queried for the following prehospital interventions: basic life support (BLS) care only, intravenous line placement only, medication given, and procedures. Advanced life support (ALS) interventions were defined as the administration of a medications or a procedure. The numbers of medications and procedures that were performed on patients in each EMD code were measured.
Thirty-one of 141 EMD and non-EMD codes met inclusion criteria and comprised 73% of all calls during the study period. Non-EMD codes accounted for 48% of all calls in this study. Patients with shortness of breath, chest pain, diabetic problems, and altered mental status received the most medications. High rates of medication administration were also seen in the following codes: 17A (fall, 27%), 17B (fall, 14%), EMDX (unable to complete EMD process, 22%), MED (medical aid requested--details to follow, 26%), and MED3 (medical aid requested by police--code 3, 18%). Procedures were performed on only 0.9% of all calls, of which 75% were related to advanced airways. Higher rates of ALS interventions in higher-acuity categories (Alpha, Bravo, etc.) were seen in a number of EMD categories, including seizure, laceration/hemorrhage, sick, and traffic accident, but not seen in many categories, including abdominal pain, falls, and chest pain.
This study demonstrated only a modest ability of the EMD system to predict which patients would require ALS intervention. There were limited differences noted in the ALS rates between the different codes (Alpha, Bravo, etc.) in the same complaint category, bringing into question the utility of the multiple subgroups. Non-EMD codes made up a large portion of calls (48%) and should be included in future studies.
医疗优先调度系统是一种紧急医疗调度（EMD）系统，广泛用于对911呼叫进行分类并优化资源分配。本研究评估了EMD和非EMD编码（未由EMD处理的呼叫）预测院前用药和操作使用情况的能力。
2004年1月1日至2006年12月31日期间，加利福尼亚州一个郊区县所有被归类为EMD或非EMD且总呼叫量超过500次的院前转运患者与其院前电子患者护理记录进行匹配。查询这些记录（N = 69541）以获取以下院前干预措施：仅基本生命支持（BLS）护理、仅静脉置管、用药和操作。高级生命支持（ALS）干预定义为用药或操作。测量了每个EMD编码下患者接受的用药和操作数量。
141个EMD和非EMD编码中有31个符合纳入标准，占研究期间所有呼叫的73%。非EMD编码占本研究中所有呼叫的48%。呼吸急促、胸痛、糖尿病问题和精神状态改变的患者用药最多。在以下编码中也观察到高用药率：17A（跌倒，27%）、17B（跌倒，14%）、EMDX（无法完成EMD流程，22%）、MED（请求医疗援助——详情随后提供，26%）和MED3（警方请求的医疗援助——3级，18%）。仅0.9%的呼叫进行了操作，其中75%与高级气道有关。在一些EMD类别中，包括癫痫发作、撕裂伤/出血、患病和交通事故，在更高 acuity 类别（Alpha、Bravo等）中观察到更高的ALS干预率，但在许多类别中未观察到，包括腹痛、跌倒和胸痛。
本研究表明EMD系统预测哪些患者需要ALS干预的能力有限。在同一主诉类别中，不同编码（Alpha、Bravo等）之间的ALS率差异有限，这使得多个亚组的实用性受到质疑。非EMD编码占呼叫的很大一部分（48%），应纳入未来研究。
