Accuracy of a Priority Medical Dispatch System in Dispatching Cardiac Emergencies in a Suburban Community

Patient safety in ambulance services: a scoping review

Background

The role of ambulance services has changed dramatically over the last few decades with the introduction of paramedics able to provide life-saving interventions, thanks to sophisticated equipment and treatments available. The number of 999 calls continues to increase, with adverse events theoretically possible with each one. Most patient safety research is based on hospital data, but little is known concerning patient safety when using ambulance services, when things can be very different. There is an urgent need to characterise the evidence base for patient safety in NHS ambulance services.

Objective

To identify and map available evidence relating to patient safety when using ambulance services.

Design

Mixed-methods design including systematic review and review of ambulance service documentation, with areas for future research prioritised using a Delphi process.

Setting and participants

Ambulance services, their staff and service users in UK.

Data sources

A wide range of data sources were explored. Multiple databases, reference lists from key papers and citations, Google and the NHS Confederation website were searched, and experts contacted to ensure that new data were included in the review. The databases MEDLINE, EMBASE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Web of Science, Science Direct, Emerald, Education Resources Information Center (ERIC), Applied Social Sciences Index and Abstracts, Social Services Abstracts, Sociological Abstracts, International Bibliography of the Social Sciences (IBSS), PsycINFO, PsycARTICLES, Health Management Information Consortium (HMIC), NHS Evidence, Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects (DARE), NHS Economic Evaluation Database (NHS EED),Health Technology Assessment, the FADE library, Current Awareness Service for Health (CASH), OpenDOAR (Directory of Open Access Repositories) and Open System for Information on Grey Literature in Europe (OpenSIGLE) and Zetoc (The British Library's Electronic Table of Contents) were searched from 1 January 1980 to 12 October 2011. Publicly available documents and issues identified by National Patient Safety Agency (NPSA), NHS Litigation Authority (NHSLA) and coroners’ reports were considered. Opinions and perceptions of senior managers, ambulance staff and service users were solicited.

Review methods

Data were extracted from annual reports using two-stage thematic analysis, data from quality accounts were collated with safety priorities tabulated and considered using thematic analysis, NPSA incident report data were collated and displayed comparatively using descriptive statistics, claims reported to NHSLA were analysed to identify number and cost of claims from mistakes and/or poor service, and summaries of coroners’ reports were assessed using thematic analysis to identify underlying safety issues. The depth of analysis is limited by the remit of a scoping exercise and availability of data.

Results

We identified studies exploring different aspects of safety, which were of variable quality and with little evidence to support activities currently undertaken by ambulance services. Adequately powered studies are required to address issues of patient safety in this service, and it appeared that national priorities were what determined safety activities, rather than patient need. There was inconsistency of information on attitudes and approaches to patient safety, exacerbated by a lack of common terminology.

Conclusion

Patient safety needs to become a more prominent consideration for ambulance services, rather than operational pressures, including targets and driving the service. Development of new models of working must include adequate training and monitoring of clinical risks. Providers and commissioners need a full understanding of the safety implications of introducing new models of care, particularly to a mobile workforce often isolated from colleagues, which requires a body of supportive evidence and an inherent critical evaluation culture. It is difficult to extrapolate findings of clinical studies undertaken in secondary care to ambulance service practice and current national guidelines often rely on consensus opinion regarding applicability to the pre-hospital environment. Areas requiring further work include the safety surrounding discharging patients, patient accidents, equipment and treatment, delays in transfer/admission to hospital, and treatment and diagnosis, with a clear need for increased reliability and training for improving handover to hospital.

Funding

The National Institute for Health Research Health Services and Delivery Research programme.

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.

Implementation of a new emergency medical communication centre organization in Finland--an evaluation, with performance indicators

Background

There is a great variety in how emergency medical communication centers (EMCC) are organized in different countries and sometimes, even within countries. Organizational changes in the EMCC have often occurred because of outside world changes, limited resources and the need to control costs, but historically there is often a lack of structured evaluation of these organization changes. The aim of this study was to evaluate if the performance in emergency medical dispatching changed in a smaller community outside Helsinki after the emergency medical call centre organization reform in Finland.

Methods

A retrospective observational study was conducted in the EMCC in southern Finland. The data from the former system, which had municipality-based centers, covered the years 2002-2005 and was collected from several databases. From the new EMCC, data was collected from January 1 to May 31, 2006. Identified performance indicators were used to evaluate and compare the old and new EMCC organizations.

Results

A total of 67 610 emergency calls were analyzed. Of these, 54 026 were from the municipality-based centers and 13 584 were from the new EMCC. Compared to the old municipality-based centers the new EMCC dispatched the highest priority to 7.4 percent of the calls compared to 3.6 percent in the old system. The high priority cases not detected by dispatchers increased significantly (p < 0.001) in the new EMCC organization, and the identification rate of unexpected deaths in the dispatched ambulance assignments was not significantly (p = 0.270) lower compared to the old municipality-based center data.

Conclusion

After implementation of a new EMCC organization in Finland the percentage and number of high priority calls increased. There was a trend, but no statistically significant increase in the emergency medical dispatchers' ability to detect patients with life-threatening conditions despite structured education, regular evaluation and standardization of protocols in the new EMCC organization.

eEmergency health care information systems

In this paper we provide an overview of the way that information and communication technologies have been used for emergency healthcare support. The paper provides a literature review of case studies exploring information systems for monitoring signals, images, medical videos, as well as information protocols used during emergency health care support, and describes future trends. We anticipate that eEmergency systems can significantly improve the delivery of healthcare during emergency cases. However, the monitoring and evaluation of these systems and especially their use in daily practice still remains a goal to be achieved.

Fusion of dispatching centres into one entity: effects on performance

BACKGROUND

Dispatching centres were fused into one of the 112 entity, which caused concerns regarding whether the medical calls could be processed effectively also in the new centre. We evaluated the effects of the reform on key performance criteria in medical calls.

METHODS

This observational study in the Helsinki Dispatching Centre consisted of two periods: Period I 2 years before the reform and Period II 2 years after. The main outcome measures were answering and call processing times, accuracy of risk assessment and appropriate use of ambulances.

RESULTS

In Period I (n=574,276), 92.2% of all incoming phone calls were answered within 10 s and in Period II (n=758,022) 82.8% (P<0.0001). Time to dispatch a first responding fire unit increased from 98 to 113 s (P<0.0001) and an advanced life support unit in category A calls increased from 73 to 84 s (P<0.0001). In Period I 47.7%, 34.8% and 17.5% of phone calls were completed in <3, 3-5 and >5 min and in Period II 29.8%, 36.1% and 34.1% (P<0.0001). The number of three studied non-transportation call types and unnecessary lights-and-siren responses increased significantly (P<0.0001 and 0.0001, respectively). Neither the accuracy of risk assessment in the three studied call types nor the rate of telephone-guided cardiopulmonary resuscitation changed.

CONCLUSIONS

The reform increased the total number of ambulance dispatches, prolonged answering and call processing times and had a negative effect on the appropriate use of ambulances. The accuracy of risk assessment was not affected. Evidence-based data should be the basis for the future as dispatching centre processes are shown to be vulnerable during organisational reforms.

Inappropriate dispatcher decision for emergency medical service users with acute myocardial infarction

OBJECTIVES

Current guidelines recommend utilization of prehospital emergency medical services (EMSs) by patients with ST-elevation myocardial infarction (STEMI). The aims of this study were to estimate the percentage of inappropriate initial dispatcher decisions and determine their impact on delays in reperfusion therapy for EMS users with STEMI.

METHODS

As part of a prospective regional registry of patients with STEMI, we analyzed the original data for 245 patients who called a university hospital-affiliated EMS call center in France. The primary study outcome was time to reperfusion therapy calculated from the documented date and time of the first patient call.

RESULTS

The initial EMS dispatcher's decision was appropriate (ie, dispatching a mobile intensive care unit staffed by an emergency or critical care physician) for 171 (70%) patients and inappropriate for 74 (30%) patients. Inappropriate decisions included referring the patient to a family physician (n = 59), providing medical advice (n = 9), and dispatching an ambulance (n = 6). Inappropriate initial decisions resulted in increased median time to reperfusion for 140 patients receiving fibrinolysis (95 vs 53 minutes; P < .001) and 91 patients undergoing primary percutaneous coronary intervention (170 vs 107 minutes; P < .001). In-hospital mortality was not different between the 2 study groups (6.8% vs 9.9%; P = .42).

CONCLUSION

The initial dispatcher's decision is inappropriate for 30% of EMS users with STEMI and results in substantial delays in time to reperfusion therapy. Accuracy of telephone triage should be improved for patients who activate EMSs in response to symptoms suggestive of acute coronary syndrome.

Paramedic determinations of medical necessity: a meta-analysis

INTRODUCTION

Reducing unnecessary ambulance transports may have operational and economic benefits for emergency medical services (EMS) agencies and receiving emergency departments. However, no consensus exists on the ability of paramedics to accurately and safely identify patients who do not require ambulance transport. Objective. This systematic review and meta-analysis evaluated studies reporting U.S. paramedics' ability to determine medical necessity of ambulance transport.

METHODS

PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Cochrane Library databases were searched using Cochrane Prehospital and Emergency Care Field search terms combined with the Medical Subject Headings (MeSH) terms "triage"; "utilization review"; "health services misuse"; "severity of illness index," and "trauma severity indices." Two reviewers independently evaluated each title to identify relevant studies; each abstract then underwent independent review to identify studies requiring full appraisal. Inclusion criteria were original research; emergency responses; determinations of medical necessity by U.S. paramedics; and a reference standard comparison. The primary outcome measure of interest was the negative predictive value (NPV) of paramedic determinations. For studies reporting sufficient data, agreement between paramedic and reference standard determinations was measured using kappa; sensitivity, specificity, and positive predictive value (PPV) were also calculated.

RESULTS

From 9,752 identified titles, 214 abstracts were evaluated, with 61 studies selected for full review. Five studies met the inclusion criteria (interrater reliability, kappa = 0.75). Reference standards included physician opinion (n = 3), hospital admission (n = 1), and a composite of physician opinion and patient clinical circumstances (n = 1). The NPV ranged from 0.610 to 0.997. Results lacked homogeneity across studies; meta-analysis using a random-effects model produced an aggregate NPV of 0.912 (95% confidence interval: 0.707-0.978). Only two studies reported complete 2 x 2 data: kappa was 0.105 and 0.427; sensitivity was 0.992 and 0.841; specificity was 0.356 and 0.581; and PPV was 0.158 and 0.823.

CONCLUSION

The results of the few studies evaluating U.S. paramedic determinations of medical necessity for ambulance transport vary considerably, and only two studies report complete data. The aggregate NPV of the paramedic determinations is 0.91, with a lower confidence limit of 0.71. These data do not support the practice of paramedics' determining whether patients require ambulance transport. These findings have implications for EMS systems, emergency departments, and third-party payers.

Geographic-Time Distribution of Ambulance Calls in Singapore: Utility of Geographic Information System in Ambulance Deployment (CARE 3)

Introduction: Pre-hospital ambulance calls are not random events, but occur in patterns and trends that are related to movement patterns of people, as well as the geographical epidemiology of the population. This study describes the geographic-time epidemiology of ambulance calls in a large urban city and conducts a time demand analysis. This will facilitate a Systems Status Plan for the deployment of ambulances based on the most cost-effective deployment strategy. Materials and Methods: An observational prospective study looking at the geographic-time epidemiology of all ambulance calls in Singapore. Locations of ambulance calls were spot-mapped using Geographic Information Systems (GIS) technology. Ambulance response times were mapped and a demand analysis conducted by postal districts. Results: Between 1 January 2006 and 31 May 2006, 31,896 patients were enrolled into the study. Mean age of patients was 51.6 years (S.D. 23.0) with 60.0% male. Race distribution was 62.5% Chinese, 19.4% Malay, 12.9% Indian and 5.2% others. Trauma consisted 31.2% of calls and medical 68.8%. 9.7% of cases were priority 1 (most severe) and 70.1% priority 2 (moderate severity). Mean call receipt to arrival at scene was 8.0 min (S.D. 4.8). Call volumes in the day were almost twice those at night, with the most calls on Mondays. We found a definite geographical distribution pattern with heavier call volumes in the suburban town centres in the Eastern and Southern part of the country. We characterised the top 35 districts with the highest call volumes by time periods, which will form the basis for ambulance deployment plans. Conclusion: We found a definite geographical distribution pattern of ambulance calls. This study demonstrates the utility of GIS with despatch demand analysis and has implications for maximising the effectiveness of ambulance deployment. Keywords: Demand analysis, Despatch, Emergency Medical Services

Accuracy in identifying patients with loss of consciousness in a police-operated emergency call centre - first step in the chain of survival

BACKGROUND

The first link in the 'chain of survival' is the activation of Emergency Medical Services (EMS). In the major part of Denmark, police officers operate the alarm 1-1-2 centre, including calls for EMS. Our aim was to study the police 1-1-2 operators' accuracy in identifying calls concerning patients with loss of consciousness as a key symptom of life-threatening conditions. 'Unconsciousness' was defined as patients with a Glasgow Coma Scale (GCS) score of < 9, scored by the on-scene anaesthesiologist from the Mobile Emergency Care Unit (MECU).

METHODS

This study was an observational cohort study based on data from the Police 1-1-2 Database and the Aarhus County Pre-hospital Database containing data from MECU cases during 6 months in 2004-05.

RESULTS

Two thousand, three hundred and forty-three emergency calls with MECU dispatch were identified. In 1655 cases, both 1-1-2 data and the GCS score were recorded. Two hundred and ninety-five patients were found with a GCS score of < 9 at MECU arrival, 243 of whom were reported 'unconscious' by 1-1-2, giving a sensitivity of 82%. One thousand, three hundred and sixty patients were found with a GCS score of > or = 9, 972 of whom were reported 'awake', giving a specificity of 72%. The positive predictive value (percentage of patients found with a GCS score of < 9 at MECU arrival amongst patients reported as 'unconscious') was 39%.

CONCLUSIONS

The accuracy was moderate with room for improvement. The positive predictive value was low, indicating over-triage of MECU.