The accuracy of medical dispatch - a systematic review

Dispatch accuracy of physician-staffed emergency medical services in trauma care in south-east Norway: a retrospective observational study

Background

Selection of incidents and accurate identification of patients that require assistance from physician-staffed emergency medical services (P-EMS) remain essential. We aimed to evaluate P-EMS availability, the underlying criteria for dispatch, and the corresponding dispatch accuracy of trauma care in south-east Norway in 2015, to identify areas for improvement.

Methods

Pre-hospital data from emergency medical coordination centres and P-EMS medical databases were linked with data from the Norwegian Trauma Registry (NTR). Based on a set of conditions (injury severity, interventions performed, level of consciousness, incident category), trauma incidents were defined as complex, warranting P-EMS assistance, or non-complex. Incident complexity and P-EMS involvement were the main determinants when assessing the triage accuracy. Undertriage was adjusted for P-EMS availability and response and transport times.

Results

Among 19,028 trauma incidents, P-EMS were involved in 2506 (13.2%). The range of overtriage was 74–80% and the range of undertriage was 20–32%. P-EMS readiness in the event of complex incidents ranged from 58 to 70%. The most frequent dispatch criterion was “Police/fire brigade request immediate response” recorded in 4321 (22.7%) of the incidents. Criteria from the groups “Accidents” and “Road traffic accidents” were recorded in 10,875 (57.2%) incidents, and criteria from the groups “Transport reservations” and “Unidentified problem” in 6025 (31,7%) incidents. Among 4916 patient pathways in the NTR, 681 (13.9%) could not be matched with pre-hospital data records.

Conclusions

Both P-EMS availability and dispatch accuracy remain suboptimal in trauma care in south-east Norway. Dispatch criteria are too vague to facilitate accurate P-EMS dispatch, and pre-hospital data is inconsistent and insufficient to provide basic data for scientific research. Future dispatch criteria should focus on the care aspect of P-EMS. Better tools for both dispatch and incident handling for the emergency medical coordination centres are essential. In general, coordination, standardisation, and integration of existing data systems should enhance the quality of trauma care and increase patient safety.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13049-021-00982-3.

Operating an eHealth System for Prehospital and Emergency Health Care Support in Light of Covid-19

Introduction: The support of prehospital and emergency call handling and the impact of Covid-19 is discussed throughout this study. The initial purpose was to create an electronic system (eEmergency system) in order to support, improve, and help the procedure of handling emergency calls. This system was expanded to facilitate needed operation changes for Covid-19.

Materials and Methods: An effort to reform the procedures followed for emergency call handling and Ambulance dispatch started on the Island of Cyprus in 2016; along that direction, a central call centre was created. The electronic system presented in this work was designed for this call centre and the new organization of the ambulance services. The main features are the support for ambulance fleet handling, the support for emergency call evaluation and triage procedure, and the improvement of communication between the call centre and the ambulance vehicles. This system started regular operation at the end of 2018. One year later, when Covid-19 period started, we expanded it with the addition of several new features in order to support the handling of patients infected with the new virus.

Results: This system has handled 112,414 cases during the last 25 months out of which 4,254 were Covid-19 cases. These cases include the transfer of patients from their house to the reference hospital, or the transfer of critical patients from the reference hospital to another hospital with an intensive care unit or transfer of patients from one hospital to another one for other reasons, like the number of admissions.

Conclusion: The main purpose of this study was to create an electronic system (eEmergency system) in order to support, improve, and help the procedure of handling emergency calls. The main components and the architecture of this system are outlined in this paper. This system is being successfully used for 25 months and has been a useful tool from the beginning of the pandemic period of Covid-19.

Live video from bystanders' smartphones to medical dispatchers in real emergencies

Background

Medical dispatchers have limited information to assess the appropriate emergency response when citizens call the emergency number. We explored whether live video from bystanders’ smartphones changed emergency response and was beneficial for the dispatcher and caller.

Methods

From June 2019 to February 2020, all medical dispatchers could add live video to the emergency calls at Copenhagen Emergency Medical Services, Denmark. Live video was established with a text message link sent to the caller’s smartphone using GoodSAM®. To avoid delayed emergency response if the video transmission failed, the medical dispatcher had to determine the emergency response before adding live video to the call. We conducted a cohort study with a historical reference group. Emergency response and cause of the call were registered within the dispatch system. After each video, the dispatcher and caller were given a questionnaire about their experience.

Results

Adding live video succeeded in 838 emergencies (82.2% of attempted video transmissions) and follow-up was possible in 700 emergency calls. The dispatchers’ assessment of the patients’ condition changed in 51.1% of the calls (condition more critical in 12.9% and less critical in 38.2%), resulting in changed emergency response in 27.5% of the cases after receiving the video (OR 1.58, 95% CI: 1.30–1.91) compared to calls without video. Video was added more frequently in cases with sick children or unconscious patients compared with normal emergency calls. The dispatcher recognized other or different disease/trauma in 9.9% and found that patient care, such as the quality of cardiopulmonary resuscitation, obstructed airway or position of the patient, improved in 28.4% of the emergencies. Only 111 callers returned the questionnaire, 97.3% of whom felt that live video should be implemented.

Conclusions

It is technically feasible to add live video to emergency calls. The medical dispatcher’s perception of the patient changed in about half of cases. The odds for changing emergency response were 58% higher when video was added to the call. However, use of live video is challenging with the existing dispatch protocols, and further implementation science is necessary.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12873-021-00493-5.

Accuracy of emergency medical services (EMS) telephone triage in identifying acute coronary syndrome (ACS) for patients with chest pain: a systematic literature review

OBJECTIVE

To systematically appraise the available evidence to determine the accuracy of decision aids for emergency medical services (EMS) telephone triage of patients with chest pain suspected to be caused by acute coronary syndrome (ACS) or life-threatening conditions.

DESIGN

Systematic review.

DATA SOURCES

Electronic searches were performed in Embase 1974, Medline 1946 and CINAHL 1937 databases from 3 March 2020 to 4 March 2020.

ELIGIBILITY CRITERIA

The review included all types of original studies that included adult patients (>18 years) who called EMS with a primary complaint of chest pain and evaluated dispatch triage priority by telephone. Outcomes of interest were a final diagnosis of ACS, acute myocardial infarction or other life-threatening conditions.

DATA EXTRACTION AND SYNTHESIS

Two authors independently extracted data on study design, population, study period, outcome and all data for assessment of accuracy, including cross-tabulation of triage priority against the outcomes of interest. Risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 assessment tool.

RESULTS

Searches identified 553 papers, of which 3 were eligible for inclusion. Those reports described the evaluation of three different prediction models with variation in the variables used to detect ACS. The overall results showed that dispatch triage tools have good sensitivity to detect ACS and life-threatening conditions, even though they are used to triage signs and symptoms rather than diagnosing the patients. On the other hand, prediction models were built to detect ACS and life-threatening conditions, and therefore, prediction models showed better sensitivity and negative predictive value than dispatch triage tools.

CONCLUSION

We have identified three prediction models for telephone triage of patients with chest pain. While they have been found to have greater accuracy than standard EMS dispatch systems, prospective external validation is essential before clinical use is considered.

PROSPERO REGISTRATION NUMBER

This systematic review was pre-registered on the International prospective register of systematic reviews (PROSPERO) database (reference CRD42020171184).

Emergency medical dispatchers' ability to identify large vessel occlusion stroke during emergency calls

Background

In acute ischemic stroke, conjugated eye deviation (CED) is an evident sign of cortical ischemia and large vessel occlusion (LVO). We aimed to determine if an emergency dispatcher can recognise LVO stroke during an emergency call by asking the caller a binary question regarding whether the patient’s head or gaze is away from the side of the hemiparesis or not. Further, we investigated if the paramedics can confirm this sign at the scene. In the group of positive CED answers to the emergency dispatcher, we investigated what diagnoses these patients received at the emergency department (ED). Among all patients brought to ED and subsequently treated with mechanical thrombectomy (MT) we tracked the proportion of patients with a positive CED answer during the emergency call.

Methods

We collected data on all stroke dispatches in the city of Tampere, Finland, from 13 February 2019 to 31 October 2020. We then reviewed all patient records from cases where the dispatcher had marked ‘yes’ to the question regarding patient CED in the computer-aided emergency response system. We also viewed all emergency department admissions to see how many patients in total were treated with MT during the period studied.

Results

Out of 1913 dispatches, we found 81 cases (4%) in which the caller had verified CED during the emergency call. Twenty-four of these patients were diagnosed with acute ischemic stroke. Paramedics confirmed CED in only 9 (11%) of these 81 patients. Two patients with positive CED answers during the emergency call and 19 other patients brought to the emergency department were treated with MT.

Conclusion

A small minority of stroke dispatches include a positive answer to the CED question but paramedics rarely confirm the emergency medical dispatcher’s suspicion of CED as a sign of LVO. Few patients in need of MT can be found this way. Stroke dispatch protocol with a CED question needs intensive implementation.

General practitioners not available - out-of-hospital emergency patients handled by anaesthesiologist in a large Norwegian municipality

BACKGROUND

Until autumn 2018 the GPs in Bergen Municipality did not attend emergency patients outside the emergency primary care centre. The ambulance staff handled emergencies on their own or were assisted by an anaesthesiologist from the helicopter emergency medical service (HEMS). The aim of this study was to investigate procedures performed by the HEMS anaesthesiologist and to assess the level of skills needed to perform these procedures.

METHODS

This study was a retrospective assessment of data from the period 2011 to 2013 on all emergency missions in which patients were dealt with by HEMS, using a rapid-response car in Bergen Municipality. All emergency missions were sorted into three categories: No intervention, Basic or Advanced intervention. This list was made by a research group with anaesthesiologists working for Bergen HEMS and GPs with OOH experience. The list is based on curriculum found in acute medicine courses.

RESULTS

HEMS responded to 716 (2.3%) out of a total of 31,696 emergencies in Bergen Municipality during the three years. In more than two-thirds (71%) of these missions, no intervention or only a basic intervention was performed. Most advanced procedures were performed in patients with cardiac arrest.

CONCLUSION

By retrospective evaluation of HEMS missions by car in Bergen municipality, we found that nearly one-third of the patients received advanced procedures. Cardiac arrest was the medical condition in which the most advanced procedures were performed. More research is needed to evaluate procedures and the importance of clinical evaluation and physicians' experience in treating these patient groups.KEY POINTSBoth HEMS and on-call GPs are needed in emergency care, and more knowledge will be useful to highlight the level of practical skills needed in these missions.There is a need for better prioritization of when to use HEMS resources and when to use on-call GPs in emergency missions.More than two-thirds of the patients involved in emergency missions received no intervention or just a basic intervention when dealt with by HEMS.This raises the issue of whether an on-call GP could have adequately treated many of the patients in this study in terms of practical skills.

Identification of new demands regarding prehospital care based on 35,188 missions in 2018

BACKGROUND

Population ageing and increased prevalence of chronic diseases result in the emergence of new demands in prehospital care. The prehospital system is facing an increase of cases without acute threat to life (so-called "non-urgent"), which generates tension due to a higher number of admissions to emergency departments and a greater use of prehospital resources. Our aim is to understand this transition in prehospital activities and to delineate the primary missions performed by paramedics in 2018 with a focus on the population concerned, the severity of cases encountered and the typology of health issues.

METHOD

The study is retrospective, and descriptive, using a statistical description of 35,188 primary missions realized in 2018 in the State of Vaud (Switzerland). The characteristics taken into consideration are the age and gender of patients, as well as the health issue, the severity of cases based on National Advisory Committee for Aeronautics score (NACA score), and the time and place of intervention.

RESULTS

The results describe the primary missions in the State of Vaud in 2018 and show that 87% of missions concern "non-urgent" situations (without acute threat to life). Over half of patients are 65 or older, the highest proportion of health issues, 49%, are medical and only 23% of missions are for traumas. Mission related to mental health issues reach 7% and those for intoxication 6%. Most missions take place between 7:00 am and 6:00 pm (67%), and around 12% of missions lead to the non-transport of the patient.

CONCLUSION

The prehospital sector is confronted with a major transition in terms of patient care. An increase of non-urgent cases is observed, associated with the care of persons aged 65 or more. Our results question the adequacy between the needs in terms of prehospital care and the paramedic profession as it is currently defined, as well as the place of this profession within the health network. Reflecting upon the role of paramedics with respect to the socio-demographic evolution of populations appears necessary, to analyse the adequacy of the paramedics' skills to respond to the current needs.

Priority accuracy by dispatch centers and Emergency Medical Services professionals in trauma patients: a cohort study

Purpose

Priority-setting by dispatch centers and Emergency Medical Services professionals has a major impact on pre-hospital triage and times of trauma patients. Patients requiring specialized care benefit from expedited transport to higher-level trauma centers, while transportation of these patients to lower-level trauma centers is associated with higher mortality rates. This study aims to evaluate the accuracy of priority-setting by dispatch centers and Emergency Medical Services professionals.

Methods

This observational study included trauma patients transported from the scene of injury to a trauma center. Priority-setting was evaluated in terms of the proportion of patients requiring specialized trauma care assigned with the highest priority (i.e., sensitivity), undertriage, and overtriage. Patients in need of specialized care were defined by a composite resource-based endpoint. An Injury Severity Score ≥ 16 served as a secondary reference standard.

Results

Between January 2015 and December 2017, records of 114,459 trauma patients were collected, of which 3327 (2.9%) patients were in need of specialized care according to the primary reference standard. Dispatch centers and Emergency Medical Services professionals assigned 83.8% and 74.5% of these patients with the highest priority, respectively. Undertriage rates ranged between 22.7 and 65.5% in the different prioritization subgroups. There were differences between dispatch and transport priorities in 17.7% of the patients.

Conclusion

The majority of patients that required specialized care were assigned with the highest priority by the dispatch centers and Emergency Medical Services professionals. Highly accurate priority criteria could improve the quality of pre-hospital triage.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00068-021-01685-1.

Emergency physician's dispatch by a paramedic-staffed emergency medical communication centre: sensitivity, specificity and search for a reference standard

Background

Some emergency medical systems (EMS) use a dispatch centre where nurses or paramedics assess emergency calls and dispatch ambulances. Paramedics may also provide the first tier of care “in the field”, with the second tier being an Emergency Physician (EP).

In these systems, the appropriateness of the decision to dispatch an EP to the first line at the same time as the ambulance has not often been measured. The main objective of this study was to compare dispatching an EP as part of the first line emergency service with the severity of the patient’s condition. The secondary objective was to highlight the need for a recognized reference standard to compare performance analyses across EMS.

Methods

This prospective observational study included all emergency calls received in Geneva’s dispatch centre between January 1st, 2016 and June 30th, 2019. Emergency medical dispatchers (EMD) assigned a level of risk to patients at the time of the initial call. Only the highest level of risk led to the dispatch of an EP. The severity of the patient’s condition observed in the field was measured using the National Advisory Committee for Aeronautics (NACA) scale. Two reference standards were proposed by dichotomizing the NACA scale. The first compared NACA≥4 with other conditions and the second compared NACA≥5 with other conditions. The level of risk identified during the initial call was then compared to the dichotomized NACA scales.

Results

97′861 assessments were included. Overall prevalence of sending an EP as first line was 13.11, 95% CI [12.90–13.32], and second line was 2.94, 95% CI [2.84–3.05]. Including NACA≥4, prevalence was 21.41, 95% CI [21.15–21.67], sensitivity was 36.2, 95% CI [35.5–36.9] and specificity 93.2 95% CI [93–93.4]. The Area Under the Receiver-Operating Characteristics curve (AUROC) of 0.7507, 95% CI [0.74734–0.75397] was acceptable. Looking NACA≥5, prevalence was 3.09, 95% CI [2.98–3.20], sensitivity was 64.4, 95% CI [62.7–66.1] and specificity 88.5, 95% CI [88.3–88.7]. We found an excellent AUROC of 0.8229, 95% CI [0.81623–0.82950].

Conclusion

The assessment by Geneva’s EMD has good specificity but low sensitivity for sending EPs. The dichotomy between immediate life-threatening and other emergencies could be a valid reference standard for future studies to measure the EP’s dispatching performance.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13049-021-00844-y.

Acute traumatic coagulopathy and the relationship to prehospital care and on-scene red blood cell transfusion

OBJECTIVE

To identify the incidence of acute traumatic coagulopathy (ATC) in trauma patients presenting to the Royal Adelaide Hospital, analyse prehospital contributors, including red blood cell transfusion and assess the clinical significance of ATC.

METHODS

A retrospective database review was undertaken using conventional coagulation assays and viscoelastic testing (ROTEM) for diagnosis of ATC.

RESULTS

Baseline ATC incidence is 10% in trauma patients, increasing to over 80% among those where the prehospital team has attended and given a transfusion of red cells. ATC was significantly associated with higher severity of trauma (odds ratio [OR] 1.11, P < 0.0001), prehospital (OR 11.8, P < 0.0001) and in-hospital blood transfusions (OR 17.9, P < 0.0001), and massive transfusions (P < 0.001).

CONCLUSIONS

Prehospital blood transfusions are given to the most severely injured trauma patients and the incidence of ATC in this group is more than 80%. There is an association with prehospital blood transfusion and increased ATC in part related to patient selection and severity of trauma, with the contribution of red cell transfusions to ATC unclear. This association should allow earlier identification of patients at increased risk of ATC to ensure rapid correction of coagulopathy to decrease the morbidity and mortality of trauma.

Improving the Appropriateness of Advanced Life Support Teams' Dispatch: A Before-After Study

BACKGROUND AND IMPORTANCE

The dispatch of Advanced Life Support (ALS) teams in Emergency Medical Services (EMS) is still a hardly studied aspect of prehospital emergency logistics. In 2015, the dispatch algorithm of Emilia Est Emergency Operation Centre (EE-EOC) was implemented and the dispatch of ALS teams was changed from primary to secondary based on triage of dispatched vehicles for high-priority interventions when teams with Immediate Life Support (ILS) skills were dispatched.

OBJECTIVES

This study aimed to evaluate the effects on the appropriateness of ALS teams' intervention and their employment time, and to compare sensitivity and specificity of the algorithm implementation.

DESIGN

This was a retrospective before-after observational study.

SETTINGS AND PARTICIPANTS

Primary dispatches managed by EE-EOC involving ambulances and/or ALS teams were included. Two groups were created on the basis of the years of intervention (2013-2014 versus 2017-2018).

INTERVENTION

A switch from primary to secondary dispatch of ALS teams in case of high-priority dispatches managed by ILS teams was implemented.

OUTCOMES

Appropriateness of ALS team intervention, total task time of ALS vehicles, and sensitivity and specificity of the algorithm were reviewed.

RESULTS

The study included 242,501 emergency calls that generated 56,567 red code dispatches. The new algorithm significantly increased global sensitivity and specificity of the system in terms of recognition of potential need of ALS intervention and the specificity of primary ALS dispatch. The appropriateness of ALS intervention was significantly increased; total tasking time per day for ALS and the number of critical dispatches without ALS available were reduced.

CONCLUSION

The revision of the dispatch criteria and the extension of the two-tiered dispatch for ALS teams significantly increased the appropriateness of ALS intervention and reduced both the global tasking time and the number of high-priority dispatches without ALS teams available.

Dispatch of a helicopter emergency medicine service to patients with a sudden, unexplained loss of consciousness of medical origin

Background

Sudden loss of consciousness (LOC) in the prehospital setting in the absence of cardiac arrest and seizure activity may be a challenge from a dispatcher’s perspective: The aetiology is varied, with many causes being transient and mostly self-limiting, whereas other causes are potentially life threatening. In this study we aim to evaluate the dispatch of HEMS to patients with LOC of medical origin, by exploring to which patients with a LOC HEMS is dispatched, which interventions HEMS teams perform in these patients, and whether HEMS interventions can be predicted by patient characteristics.

Methods

We performed retrospective cohort study of all patients with a reported unexplained LOC (e.g. not attributable to a circulatory arrest or seizures) attended by the Air Ambulance Kent, Surrey & Sussex (AAKSS), over a 4-year period (July 2013–December 2017). Primary outcome was defined as the number of HEMS-specific interventions performed in patients with unexplained LOC. Secondary outcome was the relation of clinical- and dispatch criteria with HEMS interventions being performed.

Results

During the study period, 127 patients with unexplained LOC were attended by HEMS. HEMS was dispatched directly to 25.2% of the patients, but mostly (74.8%) on request of the ground ambulance crews. HEMS interventions were performed in 65% of the patients (Prehospital Emergency Anaesthesia 56%, hyperosmolar therapy 21%, antibiotic/antiviral therapy 8%, vasopressor therapy 6%) and HEMS conveyed most patients (77%) to hospital. Acute neurological pathology was a prevalent underlying cause of unexplained LOC: 38% had gross pathology on their CT-scan upon arrival in hospital. Both GCS (r = − 0.60, p < .001) and SBP (r = 0.31, p < .001) were related to HEMS interventions being performed on scene. A GCS < 13 predicted the need for HEMS interventions in our population with a sensitivity of 94.9% and a specificity 75% (AUC 0.85).

Conclusion

HEMS dispatchers and ambulance personnel are able to identify a cohort of patients with unexplained LOC of medical origin who suffer from potentially life threatening (mainly neurological) pathology, in whom HEMS specific intervention are frequently required. Presenting GCS can be used to inform the triage process of patients with LOC at an early stage.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12873-020-00388-x.

GP decisions to participate in emergencies: a randomised vignette study

Background

GPs use their judgement on whether to participate in emergencies; however, little is known about how GPs make their decisions on emergency participation.

Aim

To test whether GPs' participation in emergencies is associated with cause of symptoms, distance to the patient, other patients waiting, and out-of-hours (OOH) clinic characteristics.

Design & setting

An online survey was sent to all GPs in Norway (n = 4701).

Method

GPs were randomised to vignettes describing a patient with acute shortness of breath and asked whether they would participate in a callout. The vignettes varied with respect to cause of symptoms (trauma versus illness), distance to the patient (15 minutes versus 45 minutes), and other patients waiting at the OOH clinic (crowding versus no crowding). The survey included questions about OOH clinic characteristics.

Results

Of the 1013 GPs (22%) who responded, 76% reported that they would participate. The proportion was higher in trauma (83% versus 69%, χ² 24.8, P<0.001), short distances (80% versus 71%, χ² 9.5, P=0.002), and no crowding (81% versus 70% χ² 14.6, P<0.001). Participation was associated with availability of a manned-response vehicle (adjusted odds ratio [OR] 2.06, 95% confidence interval [CI] = 1.25 to 3.41), and team training at the OOH clinic once a year (OR = 1.78, 95% CI = 1.12 to 2.82) or more than once a year (OR = 3.78, 95% CI = 1.64 to 8.68).

Conclusion

GPs were less likely to participate in emergencies when the incident was not owing to trauma, was far away, and when other patients were waiting. A manned-response vehicle and regular team training were associated with increased participation.

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

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.

Dispatcher Triage Accuracy in the Western Cape Government Emergency Medical Services System, Cape Town, South Africa

INTRODUCTION

Triage - the sorting of patients according to urgency of need for clinical care - is an essential part of delivering effective and efficient emergency care. But when frequent over- or under-triaging occurs, finite time and resources are diverted away from those in greatest need of care and the entire Emergency Medical Services (EMS) system is strained. In resource-constrained settings, such as South Africa, poor triage in EMS only serves to compound other contextual challenges. This study examined the accuracy of dispatcher triage over a one-year period in the Western Cape Government (WCG) EMS system in South Africa.

METHODS

A retrospective analysis of existing dispatch and EMS data to assess the accuracy of dispatch-assigned priorities was conducted. The mismatch between dispatcher-assigned call priority and triage levels determined by EMS personnel was analyzed via over- and under-triage rates, sensitivity and specificity, and positive and negative predictive values (PPVs and NPVs, respectively).

RESULTS

A total of 185,166 records from December 2016 through November 2017 were analyzed. Across all dispatch complaints, the over-triage rate was 67.6% (95% CI, 66.34-68.76) and the under-triage rate was 16.2% (95% CI, 15.44-16.90). Dispatch triage sensitivity for all included records was 49.2% (95% CI, 48.10-50.38), specificity 71.9% (95% CI, 71.00-72.92), PPV 32.5% (95% CI, 30.02-34.88), and NPV 83.8% (95% CI, 81.93-85.73).

CONCLUSION

This study provides the first evaluation of dispatch triage accuracy in the WCG EMS system, identifying that the system is suffering from both under- and over-triage. Despite variance across dispatch complaints, both under- and over-triage remained higher than widely accepted norms, and all rates were significantly above acceptable target metrics described in similar studies. Results of this study will be used to motivate the development of more rigorous training programs and resources for WCG EMS dispatchers, including improved dispatch protocols for conditions suffering from high over- and under-triage.

Enhanced dispatch and rendezvous doubles the catchment area and number of patients treated on a mobile stroke unit

INTRODUCTION

Mobile Stroke Units (MSUs) deliver acute stroke treatment on-scene in coordination with Emergency Medical Services (EMS). One criticism of the MSU approach is the limited range of a single MSU. The Houston MSU is evaluating MSU implementation, and we developed a rendezvous approach as an innovative solution to expand the range and number of patients treated.

METHODS

In addition to direct 911 dispatch of our MSU to the scene within our 7-mile catchment area, we empowered more distant EMS units to activate the MSU. We also monitored EMS radio communications to identify possible patients. For these distant patients, the MSU met the EMS unit en route to the stroke center and treated the patient at that intermediate location. The distribution of the distance from MSU base station to site of stroke and time from 911 alert to tissue plasminogen activator (tPA) bolus were compared between patients treated on-scene and by rendezvous using Wilcoxon rank sum test.

RESULTS

Over 4 years, 338 acute ischemic stroke patients were treated with tPA on our MSU. Of these, 169 (50%) were treated on-scene after MSU dispatch at a median of 6.4 miles (IQR 6.4 miles) from MSU base station. 169 (50%) were treated by 'rendezvous' pathway with assessment and treatment of stroke a median of 12.4 miles from base (IQR 5.5 miles) (p< 0.0001). Time (min) from MSU alert to tPA bolus did not differ: 36.0 ± 10.0 for on-scene vs 37.0 ± 10.0 with rendezvous (p=0.65). 13% of patients alerted via direct 911 dispatch were treated vs 44% of rendezvous patients.

CONCLUSION

Adding a rendezvous approach to an MSU dispatch pathway doubles the range of operations and the number of patients treated by an MSU in an urban area, without incurring delay.

Evolution of emergency medical services in the Kingdom of Bahrain

Emergency medical services (EMS) is crucial to any healthcare system, especially in urban countries. The Kingdom of Bahrain has always strived to develop healthcare services throughout the Kingdom including EMS. Like any other country, the Kingdom has gone through several stages in the provision of EMS. This article will focus on the development of EMS in the Kingdom and its evolution from a scattered hospital-based system to a unified system, which ensures ease of access for the population and speed of delivery to the healthcare facilities. The major focus will be the most recent national project which is the National Ambulance.

Prehospital Point-Of-Care Lactate Increases the Prognostic Accuracy of National Early Warning Score 2 for Early Risk Stratification of Mortality: Results of a Multicenter, Observational Study

The objective of this study was to assess whether the use of prehospital lactate (pLA) can increase the prognostic accuracy of the National Early Warning Score 2 (NEWS2) to detect the risk of death within 48 h. A prospective, multicenter study in adults treated consecutively by the emergency medical services (EMS) included six advanced life support (ALS) services and five hospitals. Patients were assigned to one of four groups according to their risk of mortality (low, low-medium, medium, and high), as determined by the NEWS2 score. For each group, the validity of pLA in our cohort was assessed by the area under the curve (AUC) of the receiver operating characteristic (ROC) curve. In this study, 3081 participants with a median age of 69 years (Interquartile range (IQR): 54-81) were included. The two-day mortality was 4.4% (137 cases). The scale derived from the implementation of the pLA improved the capacity of the NEWS2 to discriminate low risk of mortality, with an AUC of 0.910 (95% CI: 0.87-0.94; p < 0.001). The risk stratification provided by the NEWS2 can be improved by incorporating pLA measurement to more accurately predict the risk of mortality in patients with low risk.

Accuracy of automatic geolocalization of smartphone location during emergency calls - A pilot study

INTRODUCTION

Widespread use of smartphones allows automatic geolocalization (i.e., transmission of location data) in countless apps. Until now, this technology has not been routinely used in connection with an emergency call in which location data play a decisive role This study evaluated a new software automatically providing emergency medical service (EMS) dispatchers with a caller's geolocation. We hypothesized that this technology will provide higher accuracy, faster dispatching of EMS and a faster beginning of thoracic compressions in a cardiac arrest scenario.

MATERIAL AND METHODS

Approval from the local Ethics Committee was obtained. 108 simulated emergency calls reporting a patient in cardiac arrest were conducted at 54 metropolitan locations, which were chosen according to a realistic pattern. At each location, a conventional emergency call, with an oral description of the location, was given first; subsequently, another call using an app with automatic geolocation was placed. Accuracy of localization, time to location, time to EMS dispatch and time to first thoracic compression were compared between both groups.

RESULTS

The conventional emergency call was always successful (n = 54). Emergency call via app worked successfully in n = 46 cases (85.2%). Automatic geolocation was provided to EMS in all these n = 46 cases (100%). Deviation from estimated position to actual position was 1173.5 ± 4343.1 m for conventional and 65.6 ± 320.5 m for automatic geolocalization (p < 0.001). In addition, time to localization was significantly shorter using automatic geolocalization (34.7 vs. 71.7 s, p < 0.001). Time to first thoracic compression was significantly faster in the geolocalization group (83.0 vs. 122.6 s; p < 0.001).

CONCLUSIONS

This pilot study showed that automatic geolocalization leads to a significantly shorter duration of the emergency call, significantly shorter times until the beginning of thoracic compressions, and a higher precision in determining the location of an emergency.

A validation of machine learning-based risk scores in the prehospital setting

BACKGROUND

The triage of patients in prehospital care is a difficult task, and improved risk assessment tools are needed both at the dispatch center and on the ambulance to differentiate between low- and high-risk patients. This study validates a machine learning-based approach to generating risk scores based on hospital outcomes using routinely collected prehospital data.

METHODS

Dispatch, ambulance, and hospital data were collected in one Swedish region from 2016-2017. Dispatch center and ambulance records were used to develop gradient boosting models predicting hospital admission, critical care (defined as admission to an intensive care unit or in-hospital mortality), and two-day mortality. Composite risk scores were generated based on the models and compared to National Early Warning Scores (NEWS) and actual dispatched priorities in a prospectively gathered dataset from 2018.

RESULTS

A total of 38203 patients were included from 2016-2018. Concordance indexes (or areas under the receiver operating characteristics curve) for dispatched priorities ranged from 0.51-0.66, while those for NEWS ranged from 0.66-0.85. Concordance ranged from 0.70-0.79 for risk scores based only on dispatch data, and 0.79-0.89 for risk scores including ambulance data. Dispatch data-based risk scores consistently outperformed dispatched priorities in predicting hospital outcomes, while models including ambulance data also consistently outperformed NEWS. Model performance in the prospective test dataset was similar to that found using cross-validation, and calibration was comparable to that of NEWS.

CONCLUSIONS

Machine learning-based risk scores outperformed a widely-used rule-based triage algorithm and human prioritization decisions in predicting hospital outcomes. Performance was robust in a prospectively gathered dataset, and scores demonstrated adequate calibration. Future research should explore the robustness of these methods when applied to other settings, establish appropriate outcome measures for use in determining the need for prehospital care, and investigate the clinical impact of interventions based on these methods.

Variation in accessibility of the population to an Emergency Medical Communication Centre: a multicentre observational study

Background

Access to an Emergency Medical Communication Centre is essential for the population in emergency situations. Handling inbound calls without delay requires managing activity, process and outcome measures of the Emergency Medical Communication Centre to improve the workforce management and the level of service. France is facing political decisions on the evolution of the organisation of Emergency Medical Communication Centres to improve accessibility for the population. First, we aim to describe the variation in activity between Emergency Medical Communication Centres, and second, to explore the correlation between process measures and outcome measures.

Methods

Using telephone activity data extraction, we conducted an observational multicentre study of six French Emergency Medical Communication Centres from 1 July 2016 to 30 June 2017. We described the activity (number of incoming calls, call rate per 1000 inhabitants), process measure (agent occupation rate), and outcome measure (number of calls answered within 20 s) by hourly range and estimated the correlation between them according to the structural equation methods.

Results

A total of 52,542 h of activity were analysed, during which 2,544,254 calls were received. The annual Emergency Medical Communication Centre call rate was 285.5 [95% CI: 285.2–285.8] per 1000 inhabitants. The average hourly number of calls ranged from 29 to 61 and the call-handled rate from 75 to 98%. There are variations in activity between Emergency Medical Communication Centres. The mean agent occupation rate was correlated with the quality of service at 20 s (coefficient at − 0.54). The number of incoming calls per agent was correlated with the mean occupation rate (coefficient at 0.67). Correlation coefficients varied according to the centres and existed between different process measures.

Conclusions

The activity dynamics of the six Emergency Medical Communication Centres are not identical. This variability, illustrating the particularity of each centre, must be accurately assessed and should be taken into account in managerial considerations. The call taker occupation rate is the leverage in the workforce management to improve the population accessibility.

Predicting acute coronary syndrome in males and females with chest pain who call an emergency medical communication centre

Background

Chest pain is a frequent reason for calls in emergency medical communication centre (EMCC). Detecting a coronary origin by phone is a challenge. This is especially so as the presentations differ according to gender. We aimed to establish and validate a sex-based model to predict a coronary origin of chest pain in patients calling an EMCC.

Methods

This prospective cohort study enrolled patients at 18 years of age or older who called the EMCC because of non-traumatic chest pain. The main outcome was the diagnosis of acute coronary syndrome (ACS) determined by expert evaluation of patient files.

Results

During 18 months, 3727 patients were enrolled: 2097 (56%) men and 1630 (44%) women. ACS was diagnosed in 508 (24%) men and 139 (9%) women. For men, independent factors associated with an ACS diagnosis were age, tobacco use, severe and permanent pain; retrosternal, breathing non-related and radiating pain; and additional symptoms. The area under the receiver operating characteristic curve (AUC) was 0.76 (95% confidence interval [CI] 0.73–0.79) for predicting ACS. The accuracy of the male model to predict ACS was validated in a validation dataset (Hosmer-Lemeshow test: p = 0.554); the AUC was 0.77 (95%CI 0.73–0.80). For women, independent factors associated with an ACS diagnosis were age ≥ 60 years, personal history of coronary artery disease, and breathing non-related and radiating pain. The AUC was 0.79 (95%CI 0.75–0.83). The accuracy of the female model to predict ACS was not validated in the validation dataset (Hosmer-Lemeshow test: p = 0.035); the AUC was 0.67 (95%CI 0.60–0.74).

Conclusions

Predictors of an ACS diagnosis in patients calling an EMCC for chest pain differ between men and women. We developed an accurate predictive model for men, but for women, the accuracy was poor.

Trial registration

This study is registered with ClinicalTrials.gov (NCT02042209).

Differences between cases admitted to hospital and discharged from the emergency department after emergency medical services transport

OBJECTIVE

Rising emergency medical services (EMS) utilisation increases transport to hospital emergency departments (ED). However, some patients receive outpatient treatment (discharged) while others are hospitalised (admitted). The aims of this analysis were to compare admitted and discharged cases, to assess whether cases that were discharged from the ED could be identified using dispatch data and to compare dispatch keyword categories and hospital diagnoses.

DESIGN

Retrospective observational study using linked secondary data.

SETTING AND PARTICIPANTS

78 303 cases brought to 1 of 14 ED in the city of Munich, Germany, by EMS between 1 July 2013 and 30 June 2014.

MAIN OUTCOME MEASURES

Characteristics of admitted and discharged cases were assessed. Logistic regression was used to estimate the association between discharge and age, sex, time of day, ambulance type and dispatch keyword category. Keyword categories were compared to hospital diagnoses.

RESULTS

39.4% of cases were discharged. They were especially likely to be young (OR 10.53 (CI 9.31 to 11.92), comparing <15-year-olds to >70-year-olds) and to fall under the categories 'accidents/trauma' (OR 2.87 (CI 2.74 to 3.01)) or 'other emergencies (unspecified)' (OR 1.23 (CI 1.12 to 1.34) (compared with 'cardiovascular'). Most frequent diagnoses came from chapter 'injury and poisoning' (30.1%) of the 10th revision of the international statistical classification of disease and related health problems (ICD-10), yet these diagnoses were more frequent at discharge (42.7 vs 22.0%) whereas circulatory system disease was less frequent (2.6 vs 21.8%). Except for accidents/trauma and intoxication/poisoning many underlying diagnoses were observed for the same dispatch keyword.

CONCLUSION

Young age and dispatch for accidents or trauma were the strongest predictors of discharge. Even within the same dispatch keyword category the distribution of diagnoses differed between admitted and discharged cases. Discharge from the ED does not indicate that urgent response was unnecessary. However, these cases could be suitable for allocation to hospitals with low inpatient bed capacities and are of particular interest for future studies regarding the urgency of their condition.

Live video footage from scene to aid helicopter emergency medical service dispatch: a feasibility study

Background

Obtaining accurate information from a 112 caller is key to correct tasking of Helicopter Emergency Medical Services (HEMS). Being able to view the incident scene via video from a mobile phone may assist HEMS dispatch by providing more accurate information such as mechanism of injury and/or injuries sustained. The objective of this study is to describe the acceptability and feasibility of using live video footage from the mobile phone of a 112 caller as an HEMS dispatch aid.

Methods

Live footage is obtained via the 112 caller’s mobile phone camera through the secure GoodSAM app’s Instant-on-scene™ platform. Video footage is streamed directly to the dispatcher, and not stored. During the feasibility trial period, dispatchers noted the purpose for which they used the footage and rated ease of use and any technical- and operational issues they encountered. A subjective assessment of caller acceptance to use video was conducted.

Results

Video footage from scene was attempted for 21 emergency calls. The leading reasons listed by the dispatchers to use live footage were to directly assess the patient (18/21) and to obtain information about the mechanism of injury and the scene (11/21). HEMS dispatchers rated the ease of use with a 4.95 on a 5-point scale (range 4–5). All callers gave permission to stream from their telephone camera. Video footage from scene was successfully obtained in 19 calls, and was used by the dispatcher as an aid to send (5) or stand down (14) a Helicopter Emergency Medical Services team.

Conclusion

Live video footage from a 112 caller can be used to provide dispatchers with more information from the scene of an incident and the clinical condition of the patient(s). The use of mobile phone video was readily accepted by the 112 caller and the technology robust. Further research is warranted to assess the impact video from scene could have on HEMS dispatching.

Connect dispatch centers for call handling improves performance

The aim of this Letter to the Editor was to report a strategy to reduce time waiting for emergency calls in a dispatch center, in line with a recently published article that reviewed evidence for medical dispatching systems to accurately dispatch Emergency medical Services. Here, we tested the effect of a connected distribution of calls, where a call is allocated to the first available resource among a pooled group of telecommunicators from several dispatch centers. We found that connect dispatch centers improve dispatch center performance, especially during an overloaded period. It could be leveraged to handle emergency calls without delay and to appropriately dispatch Emergency Medical Services.