Emergency Medical Dispatch System Research Articles

Emergency medical dispatch technologies: Addressing communication challenges and coordinating emergency response in low and middle-income countries

A majority of emergency response in low and middle-income countries (LMICs) without formal emergency medical services (EMS) rely on uncoordinated layperson first responders (LFRs) to respond to emergencies using readily available mobile phones and private transport. Although formally trained LFRs are an important foundation for nascent emergency medical services (EMS) development, without coordination by standardized emergency medical dispatch (EMD) systems, LFR response is limited to witnessed emergencies, which provides significant but incomplete coverage. After training and equipping LFRs, EMD implementation using telecommunications technologies is the next step in formal EMS development and is essential to coordinate response, given the impact of timely prehospital response, intervention, and transportation on reducing morbidity/mortality. In this paper, we describe the current state of dispatch technologies used for emergency response in LMICs, focusing on the role of communication technologies, current approaches, and challenges in communication, and offer potential strategies for future development.

Optimizing an Emergency Medical Dispatch System to Improve Prehospital Diagnosis and Treatment of Acute Coronary Syndrome: Nationwide Retrospective Study in China.

Acute coronary syndrome (ACS) is the most time-sensitive acute cardiac event that requires rapid dispatching and response. The medical priority dispatch system (MPDS), one of the most extensively used types of emergency dispatch systems, is hypothesized to provide better-quality prehospital emergency treatment. However, few studies have revealed the impact of MPDS use on the process of ACS care. This study aimed to investigate whether the use of MPDS was associated with higher prehospital diagnosis accuracy and shorter prehospital delay for patients with ACS transferred by an emergency medical service (EMS), using a national database in China. This retrospective analysis was based on an integrated database of China's MPDS and hospital registry. From January 1, 2016, to December 31, 2020, EMS-treated ACS cases were divided into before MPDS and after MPDS groups in accordance with the MPDS launch time at each EMS center. The primary outcomes included diagnosis consistency between hospital admission and discharge, and prehospital delay. Multivariable logistic regression and propensity score-matching analysis were performed to compare outcomes between the 2 groups for total ACS and subtypes. A total of 9806 ACS cases (3561 before MPDS and 6245 after MPDS) treated by 43 EMS centers were included. The overall diagnosis consistency of the after MPDS group (Cohen κ=0.918, P<.001) was higher than that of the before MPDS group (Cohen κ=0.889, P<.001). After the use of the MPDS, the call-to-EMS arrival time was shortened in the matched ACS cases (20.0 vs 16.0 min, P<.001; adjusted difference: -1.67, 95% CI -2.33 to -1.02; P<.001) and in the subtype of ST-elevation myocardial infarction (adjusted difference: -3.81, 95% CI -4.63 to -2.98, P<.001), while the EMS arrival-to-door time (20.0 vs 20.0 min, P=.31) was not significantly different in all ACS cases and subtypes. The optimized use of MPDS in China was associated with increased diagnosis consistency and a reduced call-to-EMS arrival time among EMS-treated patients with ACS. An emergency medical dispatch system should be designed specifically to fit into different prehospital modes in the EMS system on a regional basis.

Evaluating feasibility of a novel mobile emergency medical dispatch tool for lay first responder prehospital response coordination in Sierra Leone: A simulation-based study

IntroductionThe global injury burden, driven by road traffic injuries, disproportionately affects low- and middle-income countries, which lack robust emergency medical services (EMS) to address injury. The WHO recommends training lay first responders (LFRs) as the first step toward formal EMS development. Emergency medical dispatch (EMD) systems are the recognized next step but whether small groups of LFRs equipped with mobile dispatch infrastructure can efficiently respond to geographically-dispersed emergencies in a timely fashion and the quality of prehospital care provided is unknown. Materials and methodsWe piloted an EMD system utilizing a mobile phone application in Sierra Leone. Ten LFRs were randomly selected from a pool of 61 highly-active LFRs trained in 2019 and recruited to participate in an emergency simulation-based study. Ten simulation scenarios were created matching proportions of injury conditions across 1,850 previous incidents (June-December 2019). Fifty total simulations were launched in randomized order over 3 months, randomized along 10 km of highway in Makeni. Replicating real-world conditions, highly-active LFR participants were blinded to randomized dispatch timing/scenario to assess response time and skill performance under direct observation with a checklist using standardized patient actors. We used novel cost data tracked during EMD pilot implementation to inform the calculation of a new cost-effectiveness ratio ($USD cost per disability-adjusted life year averted (DALY)) for LFR programs equipped with dispatch, following WHOCHOICE guidelines, which state cost-effectiveness ratios less than gross domestic product (GDP) per capita are considered “very cost-effective.” ResultsMedian total response interval (notification to arrival) was 5 min 39 s (IQR:0:03:51, 0:09:18). LFRs initially trained with a 5-hour curriculum and refresher training provide high-quality prehospital care during simulated emergencies. Median first aid skill checklist completion was 89% (IQR: 78%, 90%). Cost-effectiveness equals $179.02USD per DALY averted per 100,000 people, less than Sierra Leonean GDP per capita ($484.52USD). ConclusionLFRs equipped with mobile dispatch demonstrate appropriate response times and effective basic initial management of simulated emergencies. Training smaller cohorts of highly-active LFRs equipped with mobile dispatch appears highly cost-effective and may be a feasible model to facilitate efficient dispatch to expand emergency coverage while conserving valuable training resources in resource-limited settings.

A predictive ambulance dispatch algorithm to the scene of a motor vehicle crash: the search for optimal over and under triage rates.

BackgroundCalls for emergency medical assistance at the scene of a motor vehicle crash (MVC) substantially contribute to the demand on ambulance services. Triage by emergency medical dispatch systems is therefore important, to ensure the right care is provided to the right patient, in the right amount of time. A lights and sirens (L&S) response is the highest priority ambulance response, also known as a priority one or hot response. In this context, over triage is defined as dispatching an ambulance with lights and sirens (L&S) to a low acuity MVC and under triage is not dispatching an ambulance with L&S to those who require urgent medical care. We explored the potential for crash characteristics to be used during emergency ambulance calls to identify those MVCs that required a L&S response.MethodsWe conducted a retrospective cohort study using ambulance and police data from 2014 to 2016. The predictor variables were crash characteristics (e.g. road surface), and Medical Priority Dispatch System (MPDS) dispatch codes. The outcome variable was the need for a L&S ambulance response. A Chi-square Automatic Interaction Detector technique was used to develop decision trees, with over/under triage rates determined for each tree. The model with an under/over triage rate closest to that prescribed by the American College of Surgeons Committee on Trauma (ACS COT) will be deemed to be the best model (under triage rate of ≤ 5% and over triage rate of between 25–35%.ResultsThe decision tree with a 2.7% under triage rate was closest to that specified by the ACS COT, had as predictors—MPDS codes, trapped, vulnerable road user, anyone aged 75 + , day of the week, single versus multiple vehicles, airbag deployment, atmosphere, surface, lighting and accident type. This model had an over triage rate of 84.8%.ConclusionsWe were able to derive a model with a reasonable under triage rate, however this model also had a high over triage rate. Individual EMS may apply the findings here to their own jurisdictions when dispatching to the scene of a MVC.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12873-022-00609-5.

Comparison of Emergency Medical Dispatch Systems for Performance of Telecommunicator-Assisted Cardiopulmonary Resuscitation Among 9-1-1 Callers With Limited English Proficiency

Increasing bystander cardiopulmonary resuscitation (CPR) among racial/ethnic minority groups and culturally underserved populations is a key strategy in improving health care disparities in out-of-hospital cardiac arrest. To ascertain whether implementation of the Los Angeles Tiered Dispatch System (LA-TDS) was associated with improved performance of telecommunicator-assisted CPR (T-CPR) among 9-1-1 callers with limited English proficiency in the City of Los Angeles. This cohort study compared emergency medical services-treated, nontraumatic out-of-hospital cardiac arrest calls using the Medical Priority Dispatch System (MPDS) from January 1 to March 31, 2014, with calls using LA-TDS from January 1 to March 31, 2015. Trained data abstractors evaluated all 9-1-1 audio recordings for the initiation of T-CPR and the elapsed time to predefined events. Data were analyzed between January and December 2017. The primary outcome was the prevalence of T-CPR among 9-1-1 callers with limited English proficiency for field-confirmed nontraumatic cardiac arrests. Additional outcomes included T-CPR among callers with English proficiency and the elapsed time until key events in the call. Of the 1027 emergency medical services calls during the study periods, 597 met the inclusion criteria. A total of 289 calls (48%) were made using MPDS (263 callers with English proficiency, and 26 callers with limited English proficiency), and 308 calls (52%) were made using LA-TDS (273 callers with English proficiency, and 35 callers with limited English proficiency). No differences between MPDS and LA-TDS cohorts were found in age, sex, known comorbidities, arrest location (private vs public), or witnessed status. The prevalence of T-CPR among callers with limited English proficiency was significantly greater using LA-TDS (69%) vs MPDS (28%) (odds ratio [OR], 5.66; 95% CI, 1.79-17.85; P = .003). For callers with English proficiency, the prevalence of T-CPR improved from 55% using MPDS to 67% using LA-TDS (OR, 1.66; 95% CI, 1.15-2.41; P = .007). With LA-TDS, callers with limited English proficiency had a significant decrease in time to recognition of cardiac arrest (OR, 0.59; 95% CI, 0.41-0.84; P = .005) and dispatch of resources (OR, 0.71; 95% CI, 0.54-0.94; P = .02). The LA-TDS compared with MPDS was associated with increased performance of T-CPR for out-of-hospital cardiac arrests involving 9-1-1 callers with limited English proficiency. Further studies are needed in communities with a predominance of people with limited English proficiency to characterize bystander response, promote activation of the chain of survival, and clarify the precise elements of LA-TDS that can improve T-CPR performance.

Lessons learned from an EMS treatment in place pilot program

Emergency medical service providers are ideally positioned to help reduce unnecessary use of emergency department care. To report a qualitative analysis conducted on a “treatment in place” pilot program designed to treat low-acuity medical patients on-scene that was operated by an academic medical center and a city fire department. We conducted focus groups with fire department personnel to identify program benefits, implementation challenges, and suggestions for improvement. We reviewed 911 call notes to identify barriers and facilitators to providing on-scene care. Poor communication and training caused uncertainty about team members’ roles and how to provide care on-scene. A barrier to program success was not having an Emergency Medical Dispatch system that could identify low-acuity patients. Program benefits were its potential to save patients and insurance companies money and to educate the community about the purpose of emergency medical care. Differences in culture, communication, and resources create challenges and opportunities to interprofessional treatment in place programs.

Collaboration for preliminary design of a mobile health solution for ambulance dispatch in Rwanda

The first 60 minutes after a trauma are described as “the golden hour.” For each minute of prehospital time, the risk of dying increases by 5% (Sampalis et al., 1999). Since 90% of the global burden of injuries occur in low- and middle-income countries and lead to 5.8 million deaths annually, addressing rapid access to emergency services is critical in these settings (Nielsen et al., 2012). In most low- and middle-income countries (LMICs), there are no formal trauma systems, and many lack organized prehospital care (Nielsen et al., 2012). Emergency medical dispatch and communication systems are a foundational component of emergency medical services (World Health Organization, 2005). Yet there are no established recommendations of creating these systems inLMICs.Rwanda, a country of over 12 million people, is a rapidly developing leader in East Africa. The Ministry of Health of Rwanda established the Service d’Aide Medicale Urgente (SAMU) in 2007, recognizing the need for public emergency medical services. SAMU’s national dispatch center receives roughly 3,000 calls per month through a national 912 hotline. It organizes regional transportation with 260 total ambulances located at hospitals throughout the country and provides prehospital emergency services in the capital city of Kigali with a fleet of 12 ambulances. In the city, each ambulance has a driver, nurse and anesthetist dispatched for every call. Emergency department nursing and anesthetist staff are dispatched from hospitals around the country to respond to regional emergencies. No formal prehospital cadre of the workforce exists although the SAMU staffhave extensive field experience in prehospital care. SAMU has several challenges to rapid prehospital emergency care including lack of addresses beyond the capital city, unclear location data in densely populated areas, complex communication processes with little information about health facility capacity, and no established electronic dispatch system. The average response time for SAMU ambulances was 59 minutes in 2018, but 39% of calls were not completed within the golden hour.

Symptom-Based Dispatching in an Emergency Medical Communication Centre: Sensitivity, Specificity, and the Area under the ROC Curve.

Background: Measuring the performance of emergency medical dispatch tools used in paramedic-staffed emergency medical communication centres (EMCCs) is rarely performed. The objectives of our study were, therefore, to measure the performance and accuracy of Geneva’s dispatch system based on symptom assessment, in particular, the performance of ambulance dispatching with lights and sirens (L&S) and to measure the effect of adding specific protocols for each symptom. Methods: We performed a prospective observational study including all emergency calls received at Geneva’s EMCC (Switzerland) from 1 January 2014 to 1 July 2019. The risk levels selected during the emergency calls were compared to a reference standard, based on the National Advisory Committee for Aeronautics (NACA) scale, dichotomized to severe patient condition (NACA ≥ 4) or stable patient condition (NACA < 4) in the field. The symptom-based dispatch performance was assessed using a receiver operating characteristic (ROC) curve. Contingency tables and a Fagan nomogram were used to measure the performance of the dispatch with or without L&S. Measurements were carried out by symptom, and a group of symptoms with specific protocols was compared to a group without specific protocols. Results: We found an acceptable area under the ROC curve of 0.7474, 95%CI (0.7448–0.7503) for the 148,979 assessments included in the study. Where the severity prevalence was 21%, 95%CI (20.8–21.2). The sensitivity of the L&S dispatch was 87.5%, 95%CI (87.1–87.8); and the specificity was 47.3%, 95%CI (47.0–47.6). When symptom-specific assessment protocols were used, the accuracy of the assessments was slightly improved. Conclusions: Performance measurement of Geneva’s symptom-based dispatch system using standard diagnostic test performance measurement tools was possible. The performance was found to be comparable to other emergency medical dispatch systems using the same reference standard. However, the implementation of specific assessment protocols for each symptom may improve the accuracy of symptom-based dispatch systems.

A mixed methods investigation of emergency communications centre triage in the Government Emergency Medical Services System, Cape Town, South Africa.

IntroductionIn order to allocate resources in an effective manner, emergency medical services (EMS) systems use dispatch-based triaging to prioritise patients by acuity. Over-triage, wherein patients are assigned a higher priority level than necessary, can serve as a safety measure. However, it places strain on EMS systems, a problem believed to be experienced by South Africa's Western Cape Government EMS system, with almost half of its calls designated at the highest priority level.To begin improving dispatch within WCG EMS, we aimed to describe the current system by identifying the most common conditions dispatched, and those most perceived to be suffering from over-triage.MethodsA multi-methods approach was taken: First, a quantitative chart review was used to analyse all calls assigned a dispatch priority by WCG EMS between December 2016 and November 2017. These descriptive data then informed qualitative focus groups to further investigate emergency medical dispatch (EMD). Three focus groups were conducted, each with a convenience sample of staff from: WCG EMS staff, call takers/dispatchers, and call centre managers. Data were reviewed and coded, after which the lead researcher aggregated coded transcripts and conducted thematic content analysis.ResultsSeventy-nine condition categories were identified from 649,544 completed patient records for the study period. Non-specific pain accounted for the greatest proportion of dispatched complaints (16.88%), followed by assault with a weapon (10.00%) and respiratory complaints (9.71%).Sixteen WCG EMS personnel took part in focus groups, highlighting challenges of the current EMD system, including time constraints, legal risks, communication, overuse of the system, and lack of training. Chest pain, collapsed/unresponsive patients, and vomiting and diarrhoea were frequently noted to be potentially over-triaged conditions. To improve this, participants suggested trainings, modifications to the electronic EMD system, additional protocols, and public education.ConclusionThis study identified where over-triage is possibly occurring in the WCG EMS dispatch system, as well as potential solutions proposed by those working within the system.

119 구급 신고 전화의 한국어 증상 표현 연구

구급 신고 전화를 받는 상황요원의 신속하고 정확한 신고자 상태 파악과 적확한 조치 판단을 돕고, 정확한 다중출동을 위한 한국형 응급상황관제 시스템의 음성인식 시스템의 자동적인 처리를 지원하기 위하여 실제 구급 신고 전화의 음성 자료 분석을 통해 한국어의 응급 증상 표현 목록을 작성하고 실제 신고전화에 나타난 증상 언어표현의 특징을 파악하였다. 이러한 언어 목록과 특성들은 일선 현장의 상황요원의 교육에도 유용할 것이다. To help emergency medical dispatchers receive rapid and accurate identification and corrective action status determination of an emergency call, and to support the automatic processing of a voice recognition system to the Korean emergency medical dispatch system, emergency call records were analyzed. Furthermore, a list of Korean symptoms expression were produced and the characteristics of the symptoms that appear on the actual wording of the telephone records were identified. This language list and its characteristics will be useful for training emergency medical dispatchers.

Impact of an emergency medical dispatch system on survival from out-of-hospital cardiac arrest: a population-based study.

BackgroundIn countries where a single public emergency telephone number is not in operation, different emergency telephone numbers corresponding to multiple dispatch centres (police, fire, emergency medical service) may create confusion for the population about the most appropriate service to call. In particular, out-of-hospital cardiac arrest (OHCA) requires a prompt and effective response. We compare two different dispatch systems on OHCA patient survival at 30 days in a national system with multiple emergency telephone numbers.MethodsWe conducted an observational retrospective study of 6871 patients aged 18 years or older with presumed OHCA of cardiac origin between 2005 and 2013 in three counties of the Northern French Alps region. One county had a single dispatch centre combining medical and fire emergencies, and two had multiple dispatch centres. Propensity score matching analyses were performed to compare patient survival at 30 days.ResultsA total of 2257 emergency calls for OHCA were managed by a single dispatch centre and 4614 by a multiple dispatch centre. A single dispatch centre was associated with an increase in survival (adjusted odds ratio [OR] for all patients: 1.7; 95 % confidence interval [CI] = 1.3–2.2; p <0.001; adjusted OR for propensity-matched patients: 2.0; 95 % CI = 1.2–3.4; p = 0.012).ConclusionsA single dispatch centre was associated with a markedly improved increase of survival among OHCA patients at 30 days in a system with several emergency telephone numbers.Electronic supplementary materialThe online version of this article (doi:10.1186/s13049-016-0247-y) contains supplementary material, which is available to authorized users.

Developing emergency medical dispatch systems in Africa – Recommendations of the African Federation for Emergency Medicine/International Academies of Emergency Dispatch Working Group

Emergency medical dispatch (EMD) systems are a crucial component of effective Emergency Medical Services (EMS) systems. They provide a means of public access to emergency care information and out-of-hospital emergency care resources and expertise. EMD systems also link various components of EMS, thereby improving efficiency and performance. As EMS systems are rapidly developing across many parts of Africa, EMD systems which are context appropriate are in great need, but are mostly absent despite the wide availability of telecommunications technology. To facilitate the development of EMD systems appropriate for the African setting, the African Federation for Emergency Medicine (AFEM) and the International Academies of Emergency Dispatch (IAED) convened a working group in November 2014 to provide conceptual, technical, and innovative recommendations for contextually appropriate EMD systems for African settings. It is hoped that these recommendations will augment efficiency, effectiveness, and standardisation within and among African EMD systems, thereby improving health outcomes for sufferers of acute illness or injury.

Abstract 18631: Delayed Recognition of Cardiac Arrest in Emergency Medical Dispatch - Best Source of Key Information for System Improvement?

Background: Measuring emergency medical dispatch performance is important for both quality control and clinical outcome. Recognition of cardiac arrest is one of the key metrics when evaluating performance as it is essential for initiation of bystander CPR. It is commonly reported as either recognized or not recognized without any benchmarked definition or time limit. Little is known about the extent of delayed recognition, and if these initial delays lead to clinically relevant delays in CPR. Methods: Prospective, observational study of cardiac arrest calls during a 1 year period in Oslo and Akershus Emergency Services. Dispatch logs, ambulance records and audio files were analyzed. Recognition of cardiac arrest was reported as (1) recognized, (2) not recognized and (3) delayed recognition. Delayed recognition was defined as failure to initially clarify consciousness or abnormal breathing before moving on to further questioning regarding other symptoms or patient history. Calls across all three groups were purposefully selected, and respective dispatchers invited for interviews based on the calls they had experienced. Results: 500 cardiac arrest calls were processed of which 289 calls were included for further analysis as the dispatcher had the opportunity to recognize cardiac arrest and initiate CPR instructions. 74% of cases were recognized, 13% were not recognized and in 13% recognition was delayed. Median time to bystander CPR (first compression performed) was 2,6 (range 0.9,12.3) minutes when cardiac arrest was recognized and 5,1 (range 2.9,9.7) minutes when recognition was delayed. Interviews after calls where cardiac arrest was not recognized or delayed in recognition yielded insight into challenging areas for the dispatchers such as agonal breathing, handling health care workers as callers and non-compliance with protocol that have impacted future training and education. Conclusion: Delayed dispatch recognition of cardiac arrest is common and leads to significant delays in chest compressions. Emergency medical dispatch systems committed to improving cardiac arrest outcomes need to identify and explore all calls that challenge the system, not only those where cardiac arrest is not recognized.

Which Emergency Medical Dispatch Codes Predict High Prehospital Nontransport Rates in an Urban Community?

Background. The Medical Priority Dispatch System (MPDS) is a commonly used computer-based emergency medical dispatch (EMD) system that is widely used to prioritize 9-1-1 calls and optimize resource allocation. There are five major priority classes used to dispatch 9-1-1 calls in the San Francisco System; Alpha codes are the lowest priority (lowest expected acuity) and Echo are the highest priority. Objective. We sought to determine which MPDS dispatch codes are associated with high prehospital nontransport rates (NTRs). Methods. All unique MPDS call categories from 2009 in a highly urbanized, two-tier advanced life support (ALS) system were sorted according to highest NTRs. There are many reasons for nontransport, such as “gone on arrival,” and “patient denied transport.” Those categories with greater than 100 annual calls were further evaluated. MPDS groups that included multiple categories with NTRs exceeding 25% were then identified and each category was analyzed. Results. EMS responded to a total of 81,437 calls in 2009, of which 18,851 were not transported by EMS. The majority of the NTRs were found among “cardiac/ respiratory arrest/death,” “assault/sexual assaults,” “unknown problem/man down,” “traffic/transportation accidents,” and “unconscious/fainting.” “Cardiac or respiratory arrest/death –obvious death” (9B1) had the highest overall nontransport rate, 99.25% (1/134), most likely due to declaration of death. “Unknown problem –man down –medical alert notification” had the second highest NTR, 67.22% (138/421). However, Echo priority codes had the highest overall nontransport rates (45.45%) and Charlie had the lowest (13.84%). Conclusions. The nontransport rates of individual MPDS categories vary considerably and should be considered in any system design. We identified 52 unique call categories to have a 25% or greater NTR, 18 of which exceeded 40%. The majority of NTRs occurred among the “cardiac/respiratory arrest/death,” “assault/sexual assaults,” “unknown problem/man down,” “traffic/transportation accidents,” and “unconscious/fainting” categories. The higher the priority code within each subset (AB vs. CDE), the less likely the patient was to be transported. Charlie priority codes had a lower NTR than Delta, and Delta was lower than Echo. Charlie codes were therefore the strongest predictors of hospital transport, while Echo codes (highest priority) were those with the highest nontransport rates and were the worst predictors of hospital transport in the emergent subset.

Implementing a nationwide criteria-based emergency medical dispatch system: a register-based follow-up study

Implementing a nationwide criteria-based emergency medical dispatch system: a register-based follow-up study

Implementing a nationwide criteria-based emergency medical dispatch system: A register-based follow-up study

BackgroundA criteria-based nationwide Emergency Medical Dispatch (EMD) system was recently implemented in Denmark. We described the system and studied its ability to triage patients according to the severity of their condition by analysing hospital admission and case-fatality risks.MethodsThis was a register-based follow-up study of all 1-1-2 calls in a 6-month period that were triaged according to the Danish Index – the new criteria-based dispatch protocol. Danish Index data were linked with hospital and vital status data from national registries. Confidence intervals (95%) for proportions with binomial data were computed using exact methods. To test for trend the Wald test was used.ResultsInformation on level of emergency according to the Danish Index rating was available for 67,135 patients who received ambulance service. Emergency level A (urgent cases) accounted for 51.4% (n = 34,489) of patients, emergency level B for 46.3% (n = 31,116), emergency level C for 2.1% (n = 1,391) and emergency level D for 0.2% (n = 139). For emergency level A, the median time from call receipt to ambulance dispatch was 2 min 1 s, and the median time to arrival was 6 min 11 s. Data concerning admission and case fatality was available for 55,270 patients. The hospital admission risk for emergency level A patients was 64.4% (95% CI = 63.8-64.9). There was a significant trend (p < 0.001) towards lower admission risks for patients with lower levels of emergency. The case fatality risk for emergency level A patients on the same day as the 1-1-2 call was 4.4% (95% CI = 4.1-4.6). The relative case-fatality risk among emergency level A patients compared to emergency level B–D patients was 14.3 (95% CI: 11.5-18.0).ConclusionThe majority of patients were assessed as Danish Index emergency level A or B. Case fatality and hospital admission risks were substantially higher for emergency level A patients than for emergency level B–D patients. Thus, the newly implemented Danish criteria-based dispatch system seems to triage patients with high risk of admission and death to the highest level of emergency. Further studies are needed to determine the degree of over- and undertriage and prognostic factors.

Using PVS to support the analysis of distributed cognition systems

The rigorous analysis of socio-technical systems is challenging, because people are inherent parts of the system, together with devices and artefacts. In this paper, we report on the use of PVS as a way of analysing such systems in terms of distributed cognition. Distributed cognition is a conceptual framework that allows us to derive insights about plausible user trajectories in socio-technical systems by exploring what information in the environment provides resources for user action, but its application has traditionally required substantial craft skill. DiCoT adds structure and method to the analysis of socio-technical systems from a distributed cognition perspective. In this work, we demonstrate how PVS can be used with DiCoT to conduct a systematic analysis. We illustrate how a relatively simple use of PVS can help a field researcher to (i) externalise assumptions and facts, (ii) verify the consistency of the logical argument framed in the descriptions, (iii) help uncover latent situations that may warrant further investigation, and (iv) verify conjectures about potential hazards linked to the observed use of information resources. Evidence is also provided that formal methods and empirical studies are not alternative approaches for studying a socio-technical system, but that they can complement and refine each other. The combined use of PVS and DiCoT is illustrated through a case study concerning a real-world emergency medical dispatch system.

Emergency Medical Dispatch Codes Association with Emergency Department Outcomes

Background. Emergency medical dispatch systems are used to help categorize and prioritize emergency medical services (EMS) resources for requests for assistance. Objective. We examined whether a subset of Medical Priority Dispatch System (MPDS) codes could predict patient outcomes (emergency department [ED] discharge versus hospital admission/ED death). Methods. This retrospective observational cohort study analyzed requests for EMS through a single public safety answering point (PSAP) serving a mixed urban, suburban, and rural community over one year. Probabilistic matching was used to link subjects. Descriptive statistics, 95% confidence intervals (CIs), and logistic regression were calculated for the 107 codes and code groupings (9E vs. 9E1, 9E2, etc.) that were used 50 or more times during the study period. Results. Ninety percent of PSAP records were matched to EMS records and 84% of EMS records were matched to ED data, resulting in 26,846 subjects with complete records. The average age of the cohort was 46.2 years (standard deviation [SD] 24.8); 54% were female. Of the transported patients, 70% were discharged from the ED, with nine dispatch codes demonstrating a 90% or greater predictive power. Three code groupings had more than 60% predictive power for admission/death. Subjects aged 65 years and older were found to be at increased risk for admission/death in 33 dispatch codes (odds ratio [OR] 2.0 [95% confidence interval 1.3–3.0] to 19.6 [5.3–72.6]). Conclusions. A small subset (8% of codes; 7% by call volume) of MPDS codes were associated with greater than 90% predictive ability for ED discharge. Older adults are at increased risk for admission/death in a separate subset of MPDS codes, suggesting that age criteria may be useful to identify higher-acuity patients within the MPDS code. These findings could assist in prehospital/hospital resource management; however, future studies are needed to validate these findings for other EMS systems and to investigate possible strategies for improvements of emergency response systems.

How Well Do Emergency Medical Dispatch Codes Predict Prehospital Medication Administration in a Diverse Urban Community?

BackgroundThe Medical Priority Dispatch System (MPDS) is an emergency medical dispatch (EMD) system that is widely used to prioritize 9-1-1 calls and optimize resource allocation. MPDS is a computer-based EMD system that uses callers' responses to scripted questions to categorize cases into groups and subgroups, based on complaint and perceived acuity. ObjectiveThis study evaluates the ability of MPDS codes to predict prehospital use of medications. MethodsAll transported prehospital patients assigned a subgroup by MPDS from January 1, 2009 to December 31, 2009 in a diverse urban community were matched with their prehospital electronic patient care records. The records of transported patients dispatched through EMD were queried for prehospital interventions and matched to their MPDS classifications. Only MPDS subgroups with 10 or more calls were included in the analysis. ResultsA total of 38,005 patients met inclusion criteria. Patients with chest pain, breathing problems, heart problems, and diabetic problems received the most medications. Medications were administered in 19% of all calls. The individual MPDS subgroup with the highest rate of medication administration was 6E1A (breathing problems, 76%). Higher rates of Advanced Life Support (ALS) interventions in higher-acuity categories (e.g., Alpha, Bravo, Charlie) were seen in several EMD categories, including unconscious/fainting, breathing problems, and abdominal pain; but this was not observed in many other categories, including seizure, sick person, traumatic injury, and hemorrhage/lacerations. ConclusionsMedications were administered in 19% of all calls. There were higher rates of ALS interventions in higher-acuity categories that were not observed in many other categories.

Comparison of an advanced medical priority dispatch system (AMPDS) and a criteria based dispatch system (CBD) relating to cardiac arrest calls

Purpose of the study: For patients with cardiac arrest activation of a well-functioning emergency medical dispatch system with the ability to recognize the severity of the condition, allocate appropriate resources and provide pre-hospital treatments within a short time frame is essential as the chance of survival is known to decrease 4–6% for each minute delay.1 We have compared cardiac arrest calls processed by a US advanced medical priority dispatch (AMPDS) system to a Norwegian criteria based dispatch (CBD) system.