The Canadian National EMS Research Agenda: a mixed methods consensus study.

INTRODUCTION: Research is essential for the development of evidence-based emergency medical services (EMS) systems of care. When resources are scarce and gaps in evidence are large, a national agenda may inform the growth of EMS research in Canada. This mixed methods consensus study explores current barriers and existing strengths within Canadian EMS research, provides recommendations, and suggests EMS topics for future study. METHODS: Purposeful sampling was employed to invite EMS research stakeholders from various roles across the country. Study phases consisted of 1) baseline interviews of a subsample, 2) roundtable discussion, and 3) an online Delphi survey, in which participants scored each statement for importance. Consensus was defined a priori and met if 80% scored a statement as "important" or "very important." RESULTS: Fifty-three stakeholders participated, representing researchers (37.7%), EMS administrators (24.6%), clinicians/providers (20.7%), and educators (17.0%). Participation rates were as follows: interviews, 13 of 13 (100%); roundtable, 47 of 53 (89%); survey round 1, 50 of 53 (94%); survey round 2, 47 of 53 (89%); and survey round 3, 40 of 53 (75%). A total of 141 statements were identified as important: 20 barriers, 54 strengths/opportunities, 31 recommendations, and 36 suggested topics for future research. Like statements were synthesized, resulting in barriers (n  =  10), strengths/opportunities (n  =  24), and recommendations (n  =  19), which were categorized as time, opportunities, and funding; education and mentorship; culture of research and collaboration; structure, process, and outcome of research; EMS and paramedic practice; and the future of the EMS Research Agenda. CONCLUSION: Consensus-based key messages from this agenda should be considered when designing, funding, and publishing EMS research and will advance EMS research locally, regionally, and nationally.

Clinical events and treatment in prehospital patients with ST-segment elevation myocardial infarction.

BACKGROUND: Little is known about clinically important events and advanced care treatment that patients with ST-segment elevation myocardial infarction (STEMI) encounter in the prehospital setting. OBJECTIVES: We sought to determine the proportion of community patients with STEMI who experienced a clinically important event or received advanced care treatment prior to arrival at a designated percutaneous coronary intervention (PCI) laboratory or emergency department (ED). METHODS: We reviewed 487 consecutive community patients with STEMI between May 2008 and June 2009. All patients were geographically within a single large "third-service" urban emergency medical services (EMS) system and were transported by paramedics with an advanced care scope of practice. We recorded predefined clinically important events and advanced care treatment that occurred in patients being transported directly to a PCI laboratory or ED (group 1) or interfacility transfer to a PCI laboratory (group 2). RESULTS: One or more clinically important events occurred in 92 of 342 (26.9%) group 1 patients and nine of 145 (6.2%) group 2 patients. The most common were sinus bradycardia, hypotension, and cardiac arrest. Additionally, 33 of 342 (9.6%) group 1 and nine of 145 (6.2%) group 2 patients received one or more advanced care treatments. The most common were administration of morphine and administration of atropine. Eight group 1 patients and three group 2 patients received cardiopulmonary resuscitation (CPR) or defibrillation. CONCLUSIONS: Clinically important events and advanced care treatment are common in community STEMI patients undergoing prehospital transport or interfacility transfer to a PCI center. Several patients required CPR or defibrillation. Further research is needed to define the clinical experience of STEMI patients during the out-of-hospital phase and the scope of practice required of EMS providers to safely manage these patients.

The impact of distance on triage to trauma center care in an urban trauma system.

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

Serial prehospital 12-lead electrocardiograms increase identification of ST-segment elevation myocardial infarction.

BACKGROUND: Many prehospital protocols require acquisition of a single 12-lead electrocardiogram (ECG) when assessing a patient for ST-segment elevation myocardial infarction (STEMI). However, it is known that ECG evidence of STEMI can evolve over time. OBJECTIVES: To determine how often the first and, if necessary, second or third prehospital ECGs identified STEMI, and the time intervals associated with acquiring these ECGs and arrival at the emergency department (ED). METHODS: We retrospectively analyzed 325 consecutive prehospital STEMIs identified between June 2008 and May 2009 in a large third-service emergency medical services (EMS) system. If the first ECG did not identify STEMI, protocol required a second ECG just before transport and, if necessary, a third ECG before entering the receiving ED. Paramedics who identified STEMI at any time bypassed participating local EDs, taking patients directly to the percutaneous coronary intervention (PCI) center. Paramedics used computerized ECG interpretation with STEMI diagnosis defined as an "acute MI" report by GE/Marquette 12-SL software in ZOLL E-series defibrillator/cardiac monitors (ZOLL Medical, Chelmsford, MA). We recorded the time of each ECG, and the ordinal number of the diagnostic ECG. We then determined the number of cases and frequency of STEMI diagnosis on the first, second, or third ECG. We also measured the interval between ECGs and the interval from the initial positive ECG to arrival at the ED. Results. STEMI was identified on the first prehospital ECG in 275 cases, on the second ECG in 30 cases, and on the third ECG in 20 cases (cumulative percentages of 84.6%, 93.8%, and 100%, respectively). For STEMIs identified on the second or third ECG, 90% were identified within 25 minutes after the first ECG. The median times from identification of STEMI to arrival at the ED were 17.5 minutes, 11.0 minutes, and 0.7 minutes for STEMIs identified on the first, second, and third ECGs, respectively. CONCLUSIONS: A single prehospital ECG would have identified only 84.6% of STEMI patients. This suggests caution using a single prehospital ECG to rule out STEMI. Three serial ECGs acquired over 25 minutes is feasible and may be valuable in maximizing prehospital diagnostic yield, particularly where emergent access to PCI exists.

Methodology for the development of a Canadian national EMS research agenda.

BACKGROUND: Many health care disciplines use evidence-based decision making to improve patient care and system performance. While the amount and quality of emergency medical services (EMS) research in Canada has increased over the past two decades, there has not been a unified national plan to enable research, ensure efficient use of research resources, guide funding decisions and build capacity in EMS research. Other countries have used research agendas to identify barriers and opportunities in EMS research and define national research priorities. The objective of this project is to develop a national EMS research agenda for Canada that will: 1) explore what barriers to EMS research currently exist, 2) identify current strengths and opportunities that may be of benefit to advancing EMS research, 3) make recommendations to overcome barriers and capitalize on opportunities, and 4) identify national EMS research priorities. METHODS/DESIGN: Paramedics, educators, EMS managers, medical directors, researchers and other key stakeholders from across Canada will be purposefully recruited to participate in this mixed methods study, which consists of three phases: 1) qualitative interviews with a selection of the study participants, who will be asked about their experience and opinions about the four study objectives, 2) a facilitated roundtable discussion, in which all participants will explore and discuss the study objectives, and 3) an online Delphi consensus survey, in which all participants will be asked to score the importance of each topic discovered during the interviews and roundtable as they relate to the study objectives. Results will be analyzed to determine the level of consensus achieved for each topic. DISCUSSION: A mixed methods approach will be used to address the four study objectives. We anticipate that the keys to success will be: 1) ensuring a representative sample of EMS stakeholders, 2) fostering an open and collaborative roundtable discussion, and 3) adhering to a predefined approach to measure consensus on each topic. Steps have been taken in the methodology to address each of these a priori concerns.

The relationship between temperature and ambulance response calls for heat-related illness in Toronto, Ontario, 2005.

BACKGROUND: Concern over the adverse effects of heat on human health has led to numerous studies assessing the relationship between heat and mortality. Few studies have quantified the impact of heat on morbidity, including ambulance response calls. This study describes the association between temperature and ambulance response calls for heat-related illness (HRI) in Toronto, Ontario, Canada during the summer of 2005. METHODS: Data sources included daily temperature, relative humidity and humidex information from Environment Canada, and Medical Priority Dispatch System data from Toronto Emergency Medical Services. Time series and regression analyses were used to examine the relationship between daily temperature and ambulance response calls for HRI during the summer (1 June to 31 August) of 2005. RESULTS: In 2005, there were 201 ambulance response calls for HRI. On average, for every one degree increase in maximum temperature (°C) there was a 29% increase in ambulance response calls for HRI (p<0.0001). For every one degree increase in mean temperature (°C) there was a 32% increase in ambulance response calls for HRI (p<0.0001). CONCLUSIONS: Given these associations, we urge further exploration of ambulance response calls as a source of HRI morbidity data particularly given the increasing health concerns associated with climate change.

Does emergency medical dispatch priority predict delphi process-derived levels of prehospital intervention?

OBJECTIVE: The Medical Priority Dispatch System (MPDS) is an emergency medical dispatch system widely used to prioritize 9-1-1 calls and optimize resource allocation. This study evaluates whether the assigned priority predicts a Delphi process-derived level of prehospital intervention in each emergency medical dispatch category. METHODS: All patients given a MPDS priority in a suburban California county from 2004-2006 were included. A Delphi process of emergency medical services (EMS) professionals in another system developed the following categories of prehospital treatment representing increasing acuity, which were adapted for this study: advanced life support (ALS) intervention, ALS-Stat, and ALS-Critical. The sensitivities and specificities of MPDS priority for level of prehospital intervention were determined for each MPDS category. Likelihood ratios of low and high priority dispatch codes for the level of prehospital intervention also were calculated for each MPDS category. RESULTS: A total of 65,268 patients met inclusion criteria, representing 61% of EMS calls during the study period. The overall sensitivities of high-priority dispatch codes for ALS, ALS-Stat, and ALS-Critical interventions were 83% (95% confidence interval 83-84%), 83% (82-84%), and 94% (92-96%). Overall specificities were: ALS, 32% (31-32%); ALS-Stat, 31% (30-31%); and ALS-Critical 28% (28-29%). Compared to calls assigned to a low priority, calls with high-priority dispatch codes were more likely to receive ALS interventions by 22%, ALS-Stat by 20%, and ALS-Critical by 32%. A low priority dispatch code decreased the likelihood of ALS interventions by 48%, ALS-Stat by 45%, and ALS-Critical by 80%. Among high-priority dispatch codes, the rates of interventions were: ALS 26%, ALS-Stat 22%, and ALS-Critical 1.5%, all of which were significantly greater than low-priority calls (p<0.05) [ALS 13%, ALS-Stat 11%, and ALS-Critical 0.2%]. Major MPDS were categories with high sensitivities (>95%) for ALS interventions included breathing problems, cardiac or respiratory arrest/death, chest pain, stroke, and unconscious/fainting; these categories had an average specificity of 3%. Medical Priority Dispatch System categories such as back pain, unknown problem, and traumatic injury had sensitivities for ALS interventions<15%. CONCLUSIONS: The MPDS is moderately sensitive for the Delphi process derived ALS, ALS-Stat, and ALS-Critical intervention levels, but nonspecific. A low MPDS priority is predictive of no prehospital intervention. A high priority, however, is of little predictive value for ALS, ALS-Stat, or ALS-Critical interventions.

Evidence-based optimization of urban firefighter first response to emergency medical services 9-1-1 incidents.

INTRODUCTION: Many emergency medical services (EMS) systems dispatch nonparamedic firefighter first responders (FFRs) to selected EMS 9-1-1 calls, intending to deliver time-sensitive interventions such as defibrillation, cardiopulmonary resuscitation (CPR), and bag-mask ventilation prior to arrival of paramedics. Deciding when to send FFRs is complicated because critical cases are rare, paramedics often arrive before FFRs, and lights-and-siren responses by emergency vehicles are associated with the risk of en-route traffic collisions. OBJECTIVE: To describe a methodology allowing EMS systems to optimize their own FFR programs using local data, and reflecting local medical oversight policy and local risk-benefit opinion. METHODS: We constructed a generalized input-output model that retrospectively reviews EMS dispatch and electronic prehospital clinical records to identify a subset of Medical Priority Dispatch System (MPDS) call categories ("determinants") that maximize the opportunities for FFR interventions while minimizing unwarranted responses. Input parameters include local FFR interventions, the local FFR "first-on-scene" rate, and the locally acceptable ratio of risk to benefit. The model uses a receiver-operating characteristic (ROC) curve to identify the optimal mix of response specificity and sensitivity achieved by sending FFRs to progressively more categories of EMS calls while remaining within a defined risk-benefit ratio. The model was applied to a 16-month retrospective sample of 220,358 incidents from a large urban EMS system to compare the model's recommendations with the system's current practices. RESULTS: The model predicts that FFR lights-and-siren responses in the sample could be reduced by 83%, from 93,058 to 16,091 incidents, by confining FFR responses to 27 of 509 MPDS dispatch determinants, representing 7.3% of incidents but 58.9% of all predicted FFR interventions. Of the 93,058 incidents, another 58,275 incidents could be downgraded to safer nonemergency FFR responses and 18,692 responses could be eliminated entirely, improving the specificity of FFR response from 57.8% to 93.0%. CONCLUSIONS: This model provides a robust generalized methodology allowing EMS systems to optimize FFR lights-and-siren responses to emergency medical calls. Further validation is warranted to assess the model's generality.

Temporal and spatial variation of heat-related illness using 911 medical dispatch data.

BACKGROUND: The adverse effect of hot weather on health in urban communities is of increasing public health concern, particularly given trends in climate change. OBJECTIVES: To demonstrate the potential public health applications of monitoring 911 medical dispatch data for heat-related illness (HRI), using historical data for the summer periods (June 1-August 31) during 2002-2005 in Toronto, Ontario, Canada. METHODS: The temporal distribution of the medical dispatch calls was described in relation to a current early warning system and emergency department data from the National Ambulatory Care Reporting System (NACRS). Geospatial methods were used to map the percentage of heat-related calls in each Toronto neighborhood over the study period. RESULTS: The temporal pattern of 911 calls for HRI was similar, and sometimes peaked earlier, than current heat health warning systems (HHWS). The pattern of calls was similar to NACRS HRI visits, with the exception of 2005 where 911 calls peaked earlier. Areas of the city with a relatively higher burden of HRI included low income inner-city neighborhoods, areas with high rates of street-involved individuals, and areas along the waterfront which include summer outdoor recreational activities. CONCLUSIONS: Identifying the temporal trends and geospatial patterns of these important environmental health events has the potential to direct targeted public health interventions to mitigate associated morbidity and mortality.

Development of a surveillance case definition for heat-related illness using 911 medical dispatch data.

OBJECTIVES: The adverse effects of hot weather on public health are of increasing concern. A surveillance system using 911 medical dispatch data for the detection of heat-related illness (HRI) could provide new information on the impact of excessive heat on the population. This paper describes how we identified medical dispatch call codes, called "determinants", that could represent HRI events. METHODS: Approximately 500 medical dispatch determinants were reviewed in focus groups composed of Emergency Medical Services (EMS) paramedics, dispatchers, physicians, and public health epidemiologists. Each group was asked to select those determinants that might adequately represent HRI. Selections were then assessed empirically using correlations with daily mean temperature over the study period (June 1-August 31,2005). RESULTS: The focus groups identified 12 determinant groupings and ranked them according to specificity for HRI. Of these, "Heat/cold exposure" was deemed the most specific. The call determinant groupings with the clearest positive associations with daily mean temperature empirically were "Heat/cold exposure" (Spearman's correlation coefficient (SCC) 0.71, p < 0.0001) and "Unknown problem (man down)" (SCC 0.21, p = 0.04). Within each grouping, the determinant "Unknown status (3rd party caller)" showed significant associations, SCC = 0.34 (p = 0.001) and SCC = 0.22 (p = 0.03) respectively. CONCLUSIONS: Clinically-informed expertise and empirical evidence both contributed to identification of a group of 911 medical dispatch call determinants that plausibly represent HRI events. Once evaluated prospectively, these may be used in public health surveillance to better understand environmental health impacts on human populations and inform targeted public health interventions.

Comparison of the medical priority dispatch system to an out-of-hospital patient acuity score.

BACKGROUND: Although the Medical Priority Dispatch System (MPDS) is widely used by emergency medical services (EMS) dispatchers to determine dispatch priority, there is little evidence that it reflects patient acuity. The Canadian Triage and Acuity Scale (CTAS) is a standard patient acuity scale widely used by Canadian emergency departments and EMS systems to prioritize patient care requirements. OBJECTIVES: To determine the relationship between MPDS dispatch priority and out-of-hospital CTAS. METHODS: All emergency calls on a large urban EMS communications database for a one-year period were obtained. Duplicate calls, nonemergency transfers, and canceled calls were excluded. Sensitivity and specificity to detect high-acuity illness, as well as positive predictive value (PPV) and negative predictive value (NPV), were calculated for all protocols. RESULTS: Of 197,882 calls, 102,582 met inclusion criteria. The overall sensitivity of MPDS was 68.2% (95% confidence interval [CI] = 67.8% to 68.5%), with a specificity of 66.2% (95% CI = 65.7% to 66.7%). The most sensitive protocol for detecting high acuity of illness was the breathing-problem protocol, with a sensitivity of 100.0% (95% CI = 99.9% to 100.0%), whereas the most specific protocol was the one for psychiatric problems, with a specificity of 98.1% (95% CI = 97.5% to 98.7%). The cardiac-arrest protocol had the highest PPV (92.6%, 95% CI = 90.3% to 94.3%), whereas the convulsions protocol had the highest NPV (85.9%, 95% CI = 84.5% to 87.2%). The best-performing protocol overall was the cardiac-arrest protocol, and the protocol with the overall poorest performance was the one for unknown problems. Sixteen of the 32 protocols performed no better than chance alone at identifying high-acuity patients. CONCLUSIONS: The Medical Priority Dispatch System exhibits at least moderate sensitivity and specificity for detecting high acuity of illness or injury. This performance analysis may be used to identify target protocols for future improvements.