Schmidt Terri, Neely Keith W, Adams Annette L, Newgard Craig D, Wittwer Lynn, Muhr Marc, Norton Robert
Department of Emergency Medicine, Oregon Health & Science University, Portland, Oregon 97201, USA.
Prehosp Emerg Care. 2003 Jul-Sep;7(3):368-74. doi: 10.1080/10903120390936590.
To develop guidelines allowing emergency medical services (EMS) dispatchers to safely match callers to an EMS response or, alternatively, to a nontraditional resource.
This was a prospective cohort study of callers to an urban EMS dispatch center and an associated review of EMS patient care forms and emergency department (ED) patient care records. The following five "nature codes" (patient chief complaints) were included: back pain, fall, bleeding or laceration, sick, and trauma. Callers included in the study had been assigned the lowest severity level (Alpha), according to existing dispatch criteria. An a priori list of EMS and ED "important findings," indicating need for an EMS response, was used as the outcome variable. Classification and regression tree (CART) analysis was used to develop a decision rule to further identify a low-risk subgroup of patients who could potentially be served by alternative resources.
From November 1, 1998, to May 31, 1999, 656 subjects were entered into the study, including 263 males (40%) and 389 females (59%). The mean age was 51 years (range, 0-101 years). One hundred twenty-five (19%) callers had an important EMS finding, including the administration of comfort medications, morphine, benzodiazepines, and droperidol. Forty-six subjects (7%) had an important ED finding. When EMS and ED findings were combined, 158 subjects (24%) had an "important finding." Using CART analysis, having an age <12 years predicted a subset of patients who did not have an important finding suggesting the need for an EMS response. Using cross-validation, this decision rule had a 99% sensitivity, 13% specificity, and 98% negative predictive value.
The authors were able to use a demographic variable (age) to predict a population of callers to a 911 dispatch center triaged to the lowest acuity category, who have a very low risk of having an EMS or ED important finding. The decision rule developed here is preliminary, requiring further validation.
制定指导方针，使紧急医疗服务（EMS）调度员能够安全地将呼叫者与EMS响应相匹配，或者与非传统资源相匹配。
这是一项对城市EMS调度中心呼叫者的前瞻性队列研究，并对EMS患者护理表格和急诊科（ED）患者护理记录进行了相关回顾。纳入了以下五个“性质代码”（患者主要诉求）：背痛、跌倒、出血或撕裂伤、生病和创伤。根据现有调度标准，纳入研究的呼叫者被分配了最低严重程度级别（Alpha）。一份表明需要EMS响应的EMS和ED“重要发现”的先验列表被用作结果变量。使用分类和回归树（CART）分析来制定决策规则，以进一步识别可能由替代资源服务的低风险患者亚组。
1998年11月1日至1999年5月31日，656名受试者进入研究，其中男性263名（40%），女性389名（59%）。平均年龄为51岁（范围0 - 101岁）。125名（19%）呼叫者有重要的EMS发现，包括使用安慰性药物、吗啡、苯二氮䓬类药物和氟哌利多。46名受试者（7%）有重要的ED发现。当EMS和ED发现合并时，158名受试者（24%）有“重要发现”。使用CART分析，年龄<12岁可预测一组没有表明需要EMS响应的重要发现的患者。通过交叉验证，该决策规则的敏感性为99%，特异性为13%，阴性预测值为98%。
作者能够使用一个人口统计学变量（年龄）来预测拨打911调度中心且被分诊到最低 acuity 类别的呼叫者群体，这些呼叫者出现EMS或ED重要发现的风险非常低。这里制定的决策规则是初步的，需要进一步验证。
