Field triage systems: Methodologies from the literature

The primary goal of the Neely Conference project is to work toward defining a set of research criteria for medical necessity in emergency medical services (EMS). This paper reviews the extant literature on triage and nontransport decisions made in the field by EMS personnel, with emphasis on the methodologies that have been used to date. Two types of medical necessity standards are considered. First, there are triage criteria for determining whether a given patient requires EMS transport to the hospital, or whether an alternative might be appropriate. These triage criteria might be incorporated into protocols that field personnel could apply on scene to determine the best disposition for a given patient. Second, there are the outcome measures against which the decisions made by the field personnel are judged. In some cases, the outcome measure is the judgment of a reviewing emergency physician or nurse, while in others specific outcome measures are used to judge the performance of the criteria and the decision making of the field providers. While review of the literature shows that no “standard” set of triage criteria have been generated or validated in determining medical necessity in EMS, there are certain themes that emerge from the literature, and these themes can likely form the basis of a consensus on elements of a medical necessity criteria that need to be validated and refined. These may include (for triage criteria) vital signs, chief complaints, and physical exam findings, and (for outcome measures) hospital admission, critical events, death, and diagnosis.     

DEVELOPING RESEARCH CRITERIA TO DEFINE MEDICAL NECESSITY IN EMERGENCY MEDICAL SERVICES

“The Neely Conference: Developing Research Criteria to Define Medical Necessity in EMS” convened emergency medical services (EMS) physicians, researchers, administrators, providers, and federal agency representatives to begin the development of a set of uniform triage criteria and outcome measures that could be used to study and evaluate medical necessity among EMS patients. These standardized criteria might be used in research studies examining EMS dispatch and response (e.g., dispatch triage protocols, alternative response configurations), and EMS treatment and transport (e.g., field triage protocols, alternative care destinations). The conference process included review and analysis of the literature, expert judgment, and consensus building. There was general agreement on the following: 1. Any dispatch triage or field triage system that is developed must be designed to offer patients alternatives to EMS, not to refuse care to patients. 2. It is theoretically possible to develop a set of clinical criteria for need. Some groups of patients will clearly need a traditional EMS response and other groups will not, but this has yet to be defined. 3. In addition to clinical criteria, certain social and other nonclinical criteria such as pain or potential abuse may be used to justify a response. 4. Communication barriers, patient age, special needs, and other conditions complicate patient assessment but should not exclude patients from consideration for alternate triage or transport. 5. These research questions are important, and standard sets of outcome measures are needed so that different studies and innovative programs can be compared.     

Developing research criteria to define medical necessity in emergency medical services

“The Neely Conference: Developing Research Criteria to Define Medical Necessity in EMS” convened emergency medical services (EMS) physicians, researchers, administrators, providers, and federal agency representatives to begin the development of a set of uniform triage criteria and outcome measures that could be used to study and evaluate medical necessity among EMS patients. These standardized criteria might be used in research studies examining EMS dispatch and response (e.g., dispatch triage protocols, alternative response configurations), and EMS treatment and transport (e.g., field triage protocols, alternative care destinations). The conference process included review and analysis of the literature, expert judgment, and consensus building. There was general agreement on the following: 1. Any dispatch triage or field triage system that is developed must be designed to offer patients alternatives to EMS, not to refuse care to patients. 2. It is theoretically possible to develop a set of clinical criteria for need. Some groups of patients will clearly need a traditional EMS response and other groups will not, but this has yet to be defined. 3. In addition to clinical criteria, certain social and other nonclinical criteria such as pain or potential abuse may be used to justify a response. 4. Communication barriers, patient age, special needs, and other conditions complicate patient assessment but should not exclude patients from consideration for alternate triage or transport. 5. These research questions are important, and standard sets of outcome measures are needed so that different studies and innovative programs can be compared.     

Prehospital Trauma Triage Decision-making: A Model of What Happens between the 9-1-1 Call and the Hospital

We describe the decision-making process used by emergency medical services (EMS) providers in order to understand how 1) injured patients are evaluated in the prehospital setting; 2) field triage criteria are applied in-practice; and 3) selection of a destination hospital is determined. We conducted separate focus groups with advanced and basic life support providers from rural and urban/suburban regions. Four exploratory focus groups were conducted to identify overarching themes and five additional confirmatory focus groups were conducted to verify initial focus group findings and provide additional detail regarding trauma triage decision-making and application of field triage criteria. All focus groups were conducted by a public health researcher with formal training in qualitative research. A standardized question guide was used to facilitate discussion at all focus groups. All focus groups were audio-recorded and transcribed. Responses were coded and categorized into larger domains to describe how EMS providers approach trauma triage and apply the Field Triage Decision Scheme. We conducted 9 focus groups with 50 EMS providers. Participants highlighted that trauma triage is complex and there is often limited time to make destination decisions. Four overarching domains were identified within the context of trauma triage decision-making: 1) initial assessment; 2) importance of speed versus accuracy; 3) usability of current field triage criteria; and 4) consideration of patient and emergency care system-level factors. Field triage is a complex decision-making process which involves consideration of many patient and system-level factors. The decision model presented in this study suggests that EMS providers place significant emphasis on speed of decisions, relying on initial impressions and immediately observable information, rather than precise measurement of vital signs or systematic application of field triage criteria.     

DEFINING RESEARCH CRITERIA TO CHARACTERIZE MEDICAL NECESSITY IN EMERGENCY MEDICAL SERVICES: A CONSENSUS AMONG EXPERTS AT THE NEELY CONFERENCE

Objective. Researchers interested in ensuring appropriate use of emergency medical services (EMS) resources have attempted to define safe and effective protocols for triage either at the time of dispatch or after on-scene evaluation. Published work in this area is difficult to evaluate because protocols and outcome criteria vary from study to study. The goal of the Neely Conference was to bring together EMS experts to define a set of criteria to be used in research studies evaluating dispatch triage and field triage systems. Methods. Thirty-one experts in EMS systems and research attended a day-long workshop to assess the current literature regarding dispatch triage and field triage, and make recommendations to standardize methods used to evaluate future triage protocols. Participants were surveyed during the workshop; consensus analysis techniques were used to determine if a formal consensus was reached. A Bayesian posterior probability of 0.99 was required to consider responses a “consensus.” Results. Participants considered current evidence regarding the usefulness of EMS triage criteria to be “weak.” However, respondents agreed on a set of research criteria that could define the need for an EMS response and/or EMS transport. Field triage criteria were considered more plausible than dispatch criteria. Valid outcome criteria for assessing the effectiveness of triage protocols included ED assessment and the need for immediate surgery. Hospital admission, final diagnosis, and expert opinion were not considered adequate outcome measures. Conclusion. EMS experts agreed on a standard set of triage criteria and outcome measures for evaluating triage protocols supporting alternative forms of transport and care.     

Criteria currently used to evaluate dispatch triage systems: where do they leave us?

Some emergency medical services (EMS) systems are interested in considering the possibility of triaging some patients who call an emergency dispatch center to alternatives to the traditional emergency response, but concerns exist about the safety of that triage. In January 2003, the Neely Conference was held in association with the National Association of EMS Physicians annual meeting in Panama City, Florida. The Neely Conference began the process of developing criteria to be used in research studies evaluating dispatch and field triage systems. Various outcome measures have been used, including expert opinion, patient interviews, specific patient complaints, field findings and interventions, and emergency department or hospital outcomes. This commentary reviews the methods used in the current literature to evaluate dispatch triage systems.     

CRITERIA CURRENTLY USED TO EVALUATE DISPATCH TRIAGE SYSTEMS: WHERE DO THEY LEAVE US?

Some emergency medical services (EMS) systems are interested in considering the possibility of triaging some patients who call an emergency dispatch center to alternatives to the traditional emergency response, but concerns exist about the safety of that triage. In January 2003, the Neely Conference was held in association with the National Association of EMS Physicians annual meeting in Panama City, Florida. The Neely Conference began the process of developing criteria to be used in research studies evaluating dispatch and field triage systems. Various outcome measures have been used, including expert opinion, patient interviews, specific patient complaints, field findings and interventions, and emergency department or hospital outcomes. This commentary reviews the methods used in the current literature to evaluate dispatch triage systems.     

Defining research criteria to characterize medical necessity in emergency medical services: a consensus among experts at the neely conference

Objective

Researchers interested in ensuring appropriate use of emergency medical services (EMS) resources have attempted to define safe and effective protocols for triage either at the time of dispatch or after on-scene evaluation. Published work in this area is difficult to evaluate because protocols and outcome criteria vary from study to study. The goal of the Neely Conference was to bring together EMS experts to define a set of criteria to be used in research studies evaluating dispatch triage and field triage systems.

Methods

Thirty-one experts in EMS systems and research attended a day-long workshop to assess the current literature regarding dispatch triage and field triage, and make recommendations to standardize methods used to evaluate future triage protocols. Participants were surveyed during the workshop; consensus analysis techniques were used to determine if a formal consensus was reached. A Bayesian posterior probability of 0.99 was required to consider responses a “consensus.”

Results

Participants considered current evidence regarding the usefulness of EMS triage criteria to be “weak.” However, respondents agreed on a set of research criteria that could define the need for an EMS response and/or EMS transport. Field triage criteria were considered more plausible than dispatch criteria. Valid outcome criteria for assessing the effectiveness of triage protocols included ED assessment and the need for immediate surgery. Hospital admission, final diagnosis, and expert opinion were not considered adequate outcome measures.

Conclusion

EMS experts agreed on a standard set of triage criteria and outcome measures for evaluating triage protocols supporting alternative forms of transport and care.     

The Impact of Distance on Triage to Trauma Center Care in an Urban Trauma System

Abstract Background. Urban trauma systems are characterized by high population density, availability of trauma centers, and acceptable road transport times (within 30 minutes). In such systems, patients meeting field trauma triage (FTT) criteria should be transported directly to a trauma center, bypassing closer non-trauma centers. Objective. We evaluated emergency medical services (EMS) triage practices to identify opportunities for improving care delivery. Objective. Specifically, we evaluated the effect of the additional distance to a trauma center, compared with a closer non-trauma center, on the noncompliance with trauma destination criteria by EMS personnel in an urban environment. Methods. This was a retrospective cohort study of adults having at least one physiologic derangement and meeting Toronto EMS field trauma triage criteria from 2005 to 2010. Road travel distances between the site of injury, the closest non-trauma center, and the closest trauma center were estimated using geographic information systems. For patients who were transported to non-trauma centers, we estimated "differential distance": the additional travel distance required to transport directly to a trauma center. Logistic regression was used to analyze the effect of differential distance on triage decisions, adjusting for other patient characteristics. Results. Inclusion criteria identified 898 patients; 53% were transported directly to a trauma center. Falls, female gender, and age greater than 65?years were associated with transport to non-trauma centers. Differential distances greater than 1 mile were associated with a decreased likelihood of triage to a trauma center. Conclusion. Differential distance between the closest non-trauma center and the closest trauma center was associated with lower compliance with triage protocols, even in an urban setting where trauma centers can be accessed within approximately 30 minutes. Our findings suggest that there are opportunities for reducing the gap between ideal and actual application of field trauma triage guidelines through a process of education and feedback.     

Evidence for and Impact of Selective Reporting of Trauma Triage Mechanism Criteria

Objective: To determine whether out-of-hospital care charts selectively report trauma triage criteria, and the impact of such documentation on triage guideline development. Methods: A special structured data instrument that requested the presence or absence of the American College of Surgeons (ACS) trauma triage criteria was completed by emergency medical services (EMS) personnel transporting victims of motor vehicle crashes. The standard written EMS report forms for a subset of 199 patients with at least 1 ACS trauma triage mechanism criterion were reviewed by the investigators. Outcome data were obtained from medical record review. The structured data instrument and the standard EMS report were compared for concordance. The impact of method of data collection on the ability of the ACS criteria to predict patient outcome was determined. Results: EMS reports and structured data instruments similarly noted the presence of anatomic, physiologic, and “other” trauma triage criteria (p > 0.07 for all individual comparisons). Most mechanism-of-injury criteria noted on the data instrument (pedestrian struck >20 mph; crash speed >20 mph; vehicle deformity; compartment intrusion; rollover; and ejection) were infrequently documented on the standard EMS report (median 28.5% noted, range 0–100%). Patients who had mechanism criteria noted on the EMS report were more likely to be admitted to the hospital (44% vs 13%; p = 0.006). to require major operative procedures (10% vs 0%; p = 0.005), and to have prolonged lengths of stay (26% vs 9%; p = 0.02) and injury severity scores ±16 (15% vs 3%; p = 0.03) than were patients who had mechanism criteria documented only on the structured data instrument. Conclusions: In the authors' EMS system, standard EMS report documentation underreports ACS trauma triage mechanism criteria. This underreporting appears to bias outcome analysis in the direction of a worse outcome and more resource utilization. Reporting of mechanism-of-injury criteria improves with use of a structured data instrument.     

The impact of helicopter emergency medical service on acute ischemic stroke patients: A systematic review

BackgroundHelicopter emergency medical services (HEMS) is commonly elected transport for acute ischemic stroke (AIS) known as a time-critical illness.AimTo conduct a systematic review in order to explore the HEMS impact on healthcare status, process and outcome measures for AIS patients.MethodsA systematic search was conducted of PubMed, Medline, CINAHL, Cochrane Library and Google Scholar. The gray literature and reference lists of included articles were also searched. Thirty studies met inclusion criteria.ResultsUsing Donabedian's framework, two studies focused on the impact on healthcare structure, twenty-three explored the impact on process measures, and five focused on clinical outcomes. HEMS structure implications could not be assessed due to insufficient studies. HEMS showed no significant outcome benefit compared to ground emergency medical services (EMS) and the impact on process measures was ambiguous.ConclusionsHEMS necessity varied considerably between studies. More robust studies are needed for detection of the most suitable use of HEMS in AIS.     

EMS Provider Determinations of Necessity for Transport

Abstract

The National Association of EMS Physicians (NAEMSP) believes that in certain select situations, when it is validated to be safe in the peer-reviewed literature, emergency medical services (EMS) providers should be able to determine necessity of transport. This paper is the official position of the NAEMSP.     

Patient outcome using medical protocol to limit "lights and siren" transport

INTRODUCTION: Emergency medical services vehicle collisions (EMVCs) associated with the use of warning "lights and siren" (L&S) are responsible for injuries and death to emergency medical services (EMS) personnel and patients. This study examines patient outcome when medical protocol directs L&S transport. DESIGN: During four months, all EMS calls initiated as an emergency request for service and culminating in transport to an emergency department (ED) were included. Medical criteria determined emergent (L&S) versus non-emergent transport. Patients with worsened conditions, as reported by EMS providers, were reviewed. SETTING: Countywide suburban/rural EMS system. RESULTS: Ninety-two percent (1,495 of 1,625) of patients were transported nonemergently. Thirteen (1%) of these were reported to have worsened during transport, and none of them suffered any worsened outcome related to the non-L&S transport. CONCLUSION: This medical protocol directing the use of warning L&S during patient transport results in infrequent L&S transport. In this study, no adverse outcomes were found related to non-L&S transports.     

Use and analysis of field triage criteria for mass gatherings

INTRODUCTION: Mass gatherings may result in an acute increase in the number of people seeking medical care potentially causing undue stress to local emergency medical services (EMS) and hospitals. Often, temporary medical facilities are established within the mass gathering venue. Emergency Medical Services providers encountering patients in the field should be equipped with effective protocols to determine transport destination (venue facility vs. hospital). HYPOTHESIS: Paramedics are capable of appropriately using triage criteria written specifically for a particular mass gathering. The use of triage criteria, when applied correctly, decreases over-triage to the venue facility and undertriage to the hospital. METHODS: Paramedics triaged patients at a mass gathering to a temporary venue facility or to a single emergency department using criteria specific for the event. Cases were reviewed to determine if the patients transported went to an appropriate facility and if the triage criteria were applied appropriately. Results: Transport destination was consistent with that dictated by the criteria for 78% of cases. Analysis of these cases shows that the criteria had a sensitivity of 100% (95% CI = 58-100%) and a specificity of 90% (95% CI = 73-98%) for predicting which patients needed hospital services and which could be cared for safely in the temporary clinic setting. CONCLUSIONS: Triage by paramedics at the point of patient contact may reduce transporting of patients to hospitals unnecessarily. Patients in need of hospital services were identified. Point-of-contact triage should be applied in mass gatherings.     

Prehospital use of aspirin rarely is associated with adverse events

INTRODUCTION: Aspirin is commonly administered for acute coronary syndromes in the prehospital setting. Few studies have addressed the incidence of adverse effects associated with prehospital administration of aspirin. OBJECTIVE: To determine the incidence of adverse events following the administration of aspirin by prehospital personnel. METHODS: Multi-center, retrospective, case series that involved all patients who received aspirin in the prehospital setting from (01 August 1999-31 January 2000). Patient encounter forms of the emergency medical services (EMS) of a metropolitan fire department were reviewed. All patients who had a potential cardiac syndrome (i.e., chest pain, dyspnea) as documented on the EMS forms were included in the review. Exclusion criteria included failure to meet inclusion criteria, and chest pain secondary to apparent non-cardiac causes (i.e., trauma). Hospital charts were reviewed from a subset of patients at the participating hospitals. The major outcome was an adverse event following prehospital administration of aspirin. This outcome was evaluated during the EMS encounter, at emergency department discharge, or at six and 24-hours post-aspirin ingestion. An adverse event secondary to aspirin ingestion was defined as anaphylaxis or allergic reactions, such as rash or respiratory changes. RESULTS: A total of 25,600 EMS encounter forms were reviewed, yielding 2,399 patients with a potential cardiac syndrome. Prior to EMS arrival, 585 patients had received aspirin, and 893 were administered aspirin by EMS personnel. No patients had an adverse event during the EMS encounter. Of these patients, 229 were transported to participating hospitals and 219 medical records were available for review with no adverse reactions recorded during their hospital course. CONCLUSION: Aspirin is rarely associated with adverse events when administered by prehospital personnel for presumed coronary syndromes.     

Validity of a five-level prehospital triage system in Japan: A cohort study

BackgroundThe increasing worldwide demand for ambulance transport may worsen patient prognosis due to a prolonged response time and overcrowding in the emergency department. Triage in the prehospital setting may reduce the demand for ambulance transport by advising low-acuity patients seek non-emergency medical care. In Japan, a five-level triage system that allows emergency medical services (EMS) to triage patients has been implemented since 2014. This study aimed to validate the five-level triage system.MethodsWe conducted a retrospective cohort study in patients aged ≥16 years who were transported by EMS to a tertiary-care hospital in Japan from April 2018 to June 2018. We used admission to the intensive care unit (ICU) as the primary outcome. Our secondary outcome was overall admission. We conducted multivariable logistic regression analysis to determine the strength of association between triage acuity and admission (ICU and overall).ResultsA total of 1261 patients were included in the analysis. The odds ratios of ICU admission were 9.62 (95% confidence interval: 5.66–16.3) in Level 1 and 2.93 (95% confidence interval: 1.60–5.38) in Level 2 compared with reference groups composed of Levels 4 and 5. Similar associations were found for triage acuity and overall admission.ConclusionsOur study validates the five-level prehospital triage system for patients transported by EMS and demonstrates an association between the triage acuity and ICU admissions.     

Triage nurses’ decisions using the National Triage Scale for Australian emergency departments

The initiation of emergency care primarily depends on the decisions made by the triage nurse. Triage decisions can therefore have a profound effect on the health outcomes of patients who present for emergency care. If the National Triage Scale (NTS) was effective in providing a standardized approach to triage, a patient with a specific problem should be allocated to the same triage category, irrespective of the institution to which they present or the personnel performing the role of triage. This study examines triage nurses' level of agreement in their allocation of triage categories to patients with specific presenting problems using the NTS. Relationships between demographic characteristics of participants and triage decisions are examined and implications of any variation for triage practice and patient outcomes are explored.     

Manmade disasters

A disaster that produces a multitude of patients may severely stress a community's health-care system, from the EMS system to the hospitals. Physicians involved in such an event must realize that they will have to change their normal mode of delivering care, having to make decisions with less than the normal amount of information, and doing the most good for the most salvageable patients. Some understanding of and appreciation for the unique problems that face emergency personnel in the field are important for physicians who do not normally interact with fire and EMS personnel, because it will allow them to realize that they are not alone in the chaos of a disaster. Many manmade disasters produce patients with medical or surgical problems with which one is familiar, the only difference being the sheer number of patients. Other manmade disasters, however, most notably those involving hazardous materials and radioactive materials, are capable of producing patients who not only have unfamiliar medical problems but also have problems about which little information is readily available in the medical literature. Hospital physicians can do much to prepare themselves for these eventualities. Discussion and planning should be done among separate staffs (ICU, operating suite, emergency department), as well as among staff of the various disciplines so they can interact more effectively when a disaster occurs. Local disaster planners should receive input from hospital staffs so hospital capabilities are known and the field operation can mesh well with the hospital's operation.