A Novel Algorithm for Improving the Prehospital Diagnostic Accuracy of ST-Segment Elevation Myocardial Infarction

INTRODUCTION

Early detection of ST-segment elevation myocardial infarction (STEMI) on the prehospital electrocardiogram (ECG) improves patient outcomes. Current software algorithms optimize sensitivity but have a high false-positive rate. The authors propose an algorithm to improve the specificity of STEMI diagnosis in the prehospital setting.

METHODS

A dataset of prehospital ECGs with verified outcomes was used to validate an algorithm to identify true and false-positive software interpretations of STEMI. Four criteria implicated in prior research to differentiate STEMI true positives were applied: heart rate <130, QRS <100, verification of ST-segment elevation, and absence of artifact. The test characteristics were calculated and regression analysis was used to examine the association between the number of criteria included and test characteristics.

RESULTS

There were 44,611 cases available. Of these, 1,193 were identified as STEMI by the software interpretation. Applying all four criteria had the highest positive likelihood ratio of 353 (95% CI, 201-595) and specificity of 99.96% (95% CI, 99.93-99.98), but the lowest sensitivity (14%; 95% CI, 11-17) and worst negative likelihood ratio (0.86; 95% CI, 0.84-0.89). There was a strong correlation between increased positive likelihood ratio (r2 = 0.90) and specificity (r2 = 0.85) with increasing number of criteria.

CONCLUSIONS

Prehospital ECGs with a high probability of true STEMI can be accurately identified using these four criteria: heart rate <130, QRS <100, verification of ST-segment elevation, and absence of artifact. Applying these criteria to prehospital ECGs with software interpretations of STEMI could decrease false-positive field activations, while also reducing the need to rely on transmission for physician over-read. This can have significant clinical and quality implications for Emergency Medical Services (EMS) systems.

Older Adult Frequent 9-1-1 Callers for Emergency Medical Services in a Large Metropolitan City: Individual- and System-Level Considerations

BACKGROUND

High utilizers of 9-1-1 place a substantial burden on emergency medical services (EMS). Results of a retrospective review of records data of the City of Los Angeles Fire Department (LAFD) showed a significant increase in older adult high utilizers of 9-1-1.

OBJECTIVE

The objective of this study was to explore individual- and system-level factors implicated in EMS use among older adults, and to provide system recommendations to mitigate overuse.

METHODS

A phenomenological study was conducted, drawing from LAFD EMS records between 2012 and 2016 to identify and contact high-utilizing patients older than 50 years, their family, agency representatives, and LAFD personnel. Interviews were recorded, transcribed, and coded and a thematic analysis was completed.

RESULTS

We conducted in-depth interviews with 27 participants, including patients (n = 8), their families (n = 6), social service agency representatives (n = 3), and LAFD personnel (n = 10). The following cross-cutting themes emerged: nature of 9-1-1 calls, barriers to access, and changing the system. In addition, LAFD and social service agency representatives identified the role of EMS responders and social agency representatives. Patients and their families agreed that previous encounters and interactions with emergency care responders were relevant factors.

CONCLUSIONS

This study described reasons for 9-1-1 calls related to medical and social service needs, including mental health care. Our analysis offers insight from different stakeholders' perspectives on access to medical care and types of barriers that interfere with medical care. All groups shared recommendations to advance access to medical and mental health care.

Does Housing Status Matter in Emergency Medical Services Administration of Naloxone? A Prehospital Cross-sectional Study

Introduction: Persons experiencing homelessness (PEH) use emergency medical services (EMS) at disproportionately high rates relative to housed individuals due to several factors including disparate access to healthcare. Limited access to care is compounded by higher rates of substance use in PEH. Despite growing attention to the opioid epidemic and housing crisis, differences in EMS naloxone administration by housing status has not been systematically examined. Our objective in this study was to describe EMS administration of naloxone by housing status in the City of Los Angeles. Methods: This was a 12-month retrospective, cross-sectional analysis of electronic patient care reports (ePCRs) for all 9-1-1 EMS incidents attended by the Los Angeles Fire Department (LAFD), the sole EMS provider agency for the City of Los Angeles during the study period, January-December 2018. During this time, the City had a population of 3,949,776 with an estimated 31,825 (0.8%) PEH. We included in the study individuals to whom LAFD personnel had administered naloxone. Housing status is a mandatory field on ePCRs. The primary study outcome was the incidence of EMS naloxone administration by housing status. We used descriptive statistics and logistic regression models to examine patterns by key covariates. Results: There were 345,190 EMS incidents during the study period. Naloxone was administered during 2,428 incidents. Of those incidents 608 (25%) involved PEH, and 1,820 (75%) involved housed individuals. Naloxone administration occurred at a rate of 19 per 1,000 PEH, roughly 44 times the rate of housed individuals. A logistic regression model showed that PEH remained 2.38 times more likely to receive naloxone than their housed counterparts, after adjusting for gender, age, and respiratory depression (odds ratio 2.38, 95% confidence interval 2.15-2.64). The most common provider impressions recorded by the EMS responders who administered naloxone were the same for both groups: overdose; altered level of consciousness; and cardiac arrest. Persons experiencing homelessness who received naloxone were more likely to be male (82% vs 67%) and younger (41.4 vs 46.2 years) than housed individuals. Conclusion: In the City of Los Angeles, PEH are more likely to receive EMS-administered naloxone than their housed peers even after adjusting for other factors. Future research is needed to understand outcomes and improve care pathways for patients confronting homelessness and opioid use.

Association between a Post-Resuscitation Care Bundle and the Odds of Field Rearrest after Successful Resuscitation from Out-of-Hospital Cardiac Arrest: A Pre/Post Study

OBJECTIVES

Rearrest after successful resuscitation from out-of-hospital cardiac arrest (OHCA) is common and is associated with worse patient outcomes. However, little is known about the effect of interventions designed to prevent rearrest. We assessed the association between a prehospital care protocol for immediate management after return of spontaneous circulation (ROSC) and rates of field rearrest and survival to discharge in patients with prehospital ROSC.

METHODS

This was a retrospective study of adult patients with OHCA and field ROSC within a large EMS system before (April 2017-August 2018) and after (April 2019-February 2020) implementation of a structured prehospital post-ROSC care protocol. The protocol was introduced in September 2018 and provided on-scene stabilization direction including guidance on ventilation and blood pressure support. Field data and hospital outcomes were used to compare the frequency of field rearrest, hospital survival, and survival with good neurologic outcome before and after protocol implementation. Logistic regression was used to assess the association between the post-implementation period and these outcomes, and odds ratios were reported. The association between individual interventions on these outcomes was also explored.

RESULTS

There were 2,706 patients with ROSC after OHCA in the pre-implementation period and 1,780 patients in the post-implementation period. The rate of prehospital rearrest was 43% pre-implementation vs 45% post-implementation (RD 2%, 95% CI -1, 4%). In the adjusted analysis, introduction of the protocol was not associated with decreased odds of rearrest (OR 0.87, 95% CI 0.73, 1.04), survival to hospital discharge (OR 1.01, 95% CI 0.81, 1.24), or survival with good neurologic outcome (OR 0.81, 95% CI 0.61, 1.06). Post-implementation, post-ROSC administration of saline and push-dose epinephrine increased from 11% to 25% (RD 14%, 95% CI 11, 17%) and from 3% to 12% (RD 9% 95% CI 7, 11%), respectively. In an exploratory analysis, push-dose epinephrine was associated with a decreased odds of rearrest (OR 0.68, 95% CI 0.50, 0.94).

CONCLUSIONS

Introduction of a post-ROSC care protocol for patients with prehospital ROSC after OHCA was not associated with reduced odds of field rearrest. When elements of the care bundle were considered individually, push-dose epinephrine was associated with decreased odds of rearrest.

Implementation of a regional extracorporeal membrane oxygenation program for refractory ventricular fibrillation out-of-hospital cardiac arrest

BACKGROUND

eCPR, the modality of extracorporeal membrane oxygenation (ECMO) applied in the setting of cardiac arrest, has emerged as a novel therapy which may improve outcomes in select patients with out-of-hospital cardiac arrest (OHCA). To date, implementation has been mainly limited to single academic centres. Our objective is to describe the feasibility and challenges with implementation of a regional protocol for eCPR.

METHODS

The Los Angeles County Emergency Medical Services (EMS) Agency implemented a regional eCPR protocol in July 2020, which included coordination across multiple EMS provider agencies and hospitals to route patients with refractory ventricular fibrillation (rVF) OHCA to eCPR-capable centres (ECCs). Data were entered on consecutive patients with rVF with suspected cardiac aetiology into a centralized database including time intervals, field and in-hospital care, survival and neurologic outcome.

RESULTS

From July 27, 2020 through July 31, 2022, 35 patients (median age 57 years, 6 (17%) female) were routed to ECCs, of whom 11 (31%) received eCPR and 3 (27%) treated with eCPR survived, all of whom had a full neurologic recovery. Challenges encountered during implementation included cost to EMS provider agencies for training, implementation, and purchase of automatic chest compression devices, maintenance of system awareness, hospital administrative support for staffing and equipment for the ECMO program, and interdepartmental coordination at ECCs.

CONCLUSION

We describe the successful implementation of a regional eCPR program with ongoing patient enrolment and data collection. These preliminary findings can serve as a model for other EMS systems who seek to implement regional eCPR programs.

FREQUENT USERS OF EMERGENCY MEDICAL SERVICES IN A METROPOLITAN CITY: INDIVIDUAL- AND SYSTEM-LEVEL CONSIDERATIONS

Frequent 911 calls from older adults place a significant burden on emergency response systems. Drawing from key informant interviews, we explore factors implicated in repeated Emergency Medical Services (EMS) among older people in the City of Los Angeles and provide system and policy recommendations to mitigate overuse of EMS 911 calls. Los Angeles Fire Department (LAFD) dispatch call records documented 370,016 EMS encounters from 202,471 unique individuals over 50 from 2012 to 2016. Frequent 911 callers over the age of 50 (n=8), family members (n=6), Los Angeles Fire Department (LAFD) personnel (n=10), and community service providers (n=3) participated in in-depth, qualitative interviews to understand individual- and system-level factors that increase the likelihood of repeated calls. All interviews were audio recorded, transcribed, and analyzed thematically. Guided by Grounded Theory, two themes emerged across all interviewee groups pointing to factors that contributed to 911 calls: 1) The Nature of 911 Calls; 2) Barriers to Access. Patients and family members were aligned on a third theme: 3) Previous Encounters: Interactions with emergency care providers, while LAFD and service providers were in agreement on a fourth theme: 4) The Role of EMS Responders and Community Providers. All groups provided recommendations for the theme, 5) Change the System so that 911 calls do not serve as the default choice. Findings demonstrate the need to improve coordination between LAFD, medical and human service providers. Care coordination can support individual- and system-level supports for patients and families to address their needs and reduce repeated EMS use.

Cognitive load during training for out-of-department emergency responses

Background

Emergency medicine (EM) physicians sometimes respond to critical events outside the emergency department. To prepare for these complex cases-typically called "rapid responses" (RRs)-EM residents receive simulation-based training involving four practice tasks and three exam tasks during a 1-day session. Cognitive load (CL) theory describes how humans function with limited working memories to perform complex tasks. RRs are expected to generate high levels of CL, but the profile of CL across providers and RR cases is not well understood. In this study, we analyzed resident's CL during RR training. We hypothesized variations in CL across individual and case and that exam cases would cause higher CLs than practice cases.

Methods

Residents anonymously self-reported CL levels after each case using the Paas scale, a single-item, 9-point scale from "very, very low CL" to "very, very high CL." To examine case-based differences in CL, data were rescaled by individual residents. "High CL" was defined as a score of 9/9.

Results

Among 18 residents participating, CLs ranged from 4 to 9, with median of 7 and interquartile range of 7-8. While many cases showed bell curve-like distributions of CLs, one case-a bleeding tracheostomy-showed a rightward skew reflecting higher levels of CL. No significant difference was found in CL between practice and exam cases. There were 20 reports (16.5%) of "high" CL with variation across residents (0/7 [0%] to 5/6 [83.3%] cases) and across cases (1/18 [5.6%) to 8/18 [44.4%]).

Conclusions

The CL that EM residents experienced did show considerable interpersonal and intercase variation, but there was no significant difference between practice and exam cases. These results highlight several questions about how to optimally design future training, including how best to balance low and high CL training cases and which cases may require further training.

Abstract 22: Geospatial Modeling To Optimize Mobile Stroke Unit System Deployment In A Large Metropolitan Region

Introduction: Transition from evidence to practice is the next challenge for Mobile Stroke Units (MSUs) now that two controlled studies have shown improved outcomes (BEST-MSU and B_PROUD). This requires successful integration into EMS systems. We sought to utilize geospatial mapping to identify the most efficient number and positioning of MSUs in Los Angeles (LA) County to maximize patient access.

Methods: LA County has one of the largest EMS systems in the US, comprising 88 cities, more than 4000 sq miles, and a population of 10.2 million. Using ESRI/ArcGIS software, we performed geospatial mapping of all 911 calls resulting in a final diagnosis stroke from July 2016 - June 2019, converting street addresses to latitude/longitude. Regional heatmaps of stroke call volume were generated for day/evening (7 am-10 pm) vs nighttime (10 pm-7 am) and ischemic vs hemorrhagic stroke, superimposed upon available stroke centers and neighborhood sociodemographic factors. Based on pilot experience, each MSU was projected to be able to service a 10-mile radius.

Results: Among 10,818 EMS responses for acute cerebrovascular disease during the 3-year study period, calls occurred during day/evening in 84.5% and nighttime in 15.5%. Stroke type was ischemic in 78.8% and hemorrhagic in 21.2%. Heat maps revealed multifocal geographic hotspots, with most active locations somewhat different for day/evening vs night and ischemic vs hemorrhagic. The spatial analysis algorithm determined that optimal placement of 5 MSUs in highest incidence areas would provide coverage for 87.0% of county stroke events. Positioning of 2 additional units in geographically isolated perimeter areas increased coverage to 91.9% of stroke events (Figure).

Conclusions: Geospatial modeling can delineate the most efficient positioning of MSU resources within regionalized EMS systems of stroke care. Optimal position varies with time of day and with prioritization of coverage for ischemic vs hemorrhagic stroke.

Spatiotemporal analysis of out-of-hospital cardiac arrest in the City of Los Angeles, 2011-2019

OBJECTIVE

The goal of this analysis is to spatiotemporally identify and categorize areas in a large urban city according to Out-of-Hospital Cardiac Arrest (OHCA) rates and No Bystander CPR (NBCPR) risk levels.

STUDY AREA AND PARTICIPANTS

The study comprised all cardiac arrests within the administrative geographic boundary of the City of Los Angeles. The final sample included 15,904 cases that were geolocated within 985 census tracts.

MAIN OUTCOMES AND MEASURES

The primary outcome was stratification of census tracts into risk levels of OHCA and NBCPR by observed spatiotemporal patterns.

RESULTS

Of 985 census tracts in the analytical sample, 182 census tracts (18.5%) were identified as having higher risk of OHCA and NBCPR. This assessment resulted in 129 census tracts in Tier 3 (moderate risk), 36 in Tier 2 (moderate-high risk), and 17 in Tier 1 (highest risk). Census tracts in Tiers 2 and 3 had higher amounts incident OHCA, while those in tier 1 had more OHCA events with NBCPR. These areas were largely contiguous and located in the Central and South areas of Los Angeles.

CONCLUSIONS

Using a novel three-tiered neighborhood risk classification tool, specific neighborhoods have been identified in the second largest city in the U.S. with consistently high or accelerating rates of OHCA and low bystander CPR. Further study of bystander response and community-based public health campaigns are needed in these communities.

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

IMPORTANCE

Increasing bystander cardiopulmonary resuscitation (CPR) among racial/ethnic minority groups and culturally underserved populations is a key strategy in improving health care disparities in out-of-hospital cardiac arrest.

OBJECTIVE

To ascertain whether implementation of the Los Angeles Tiered Dispatch System (LA-TDS) was associated with improved performance of telecommunicator-assisted CPR (T-CPR) among 9-1-1 callers with limited English proficiency in the City of Los Angeles.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study compared emergency medical services-treated, nontraumatic out-of-hospital cardiac arrest calls using the Medical Priority Dispatch System (MPDS) from January 1 to March 31, 2014, with calls using LA-TDS from January 1 to March 31, 2015. Trained data abstractors evaluated all 9-1-1 audio recordings for the initiation of T-CPR and the elapsed time to predefined events. Data were analyzed between January and December 2017.

MAIN OUTCOMES AND MEASURES

The primary outcome was the prevalence of T-CPR among 9-1-1 callers with limited English proficiency for field-confirmed nontraumatic cardiac arrests. Additional outcomes included T-CPR among callers with English proficiency and the elapsed time until key events in the call.

RESULTS

Of the 1027 emergency medical services calls during the study periods, 597 met the inclusion criteria. A total of 289 calls (48%) were made using MPDS (263 callers with English proficiency, and 26 callers with limited English proficiency), and 308 calls (52%) were made using LA-TDS (273 callers with English proficiency, and 35 callers with limited English proficiency). No differences between MPDS and LA-TDS cohorts were found in age, sex, known comorbidities, arrest location (private vs public), or witnessed status. The prevalence of T-CPR among callers with limited English proficiency was significantly greater using LA-TDS (69%) vs MPDS (28%) (odds ratio [OR], 5.66; 95% CI, 1.79-17.85; P = .003). For callers with English proficiency, the prevalence of T-CPR improved from 55% using MPDS to 67% using LA-TDS (OR, 1.66; 95% CI, 1.15-2.41; P = .007). With LA-TDS, callers with limited English proficiency had a significant decrease in time to recognition of cardiac arrest (OR, 0.59; 95% CI, 0.41-0.84; P = .005) and dispatch of resources (OR, 0.71; 95% CI, 0.54-0.94; P = .02).

CONCLUSIONS AND RELEVANCE

The LA-TDS compared with MPDS was associated with increased performance of T-CPR for out-of-hospital cardiac arrests involving 9-1-1 callers with limited English proficiency. Further studies are needed in communities with a predominance of people with limited English proficiency to characterize bystander response, promote activation of the chain of survival, and clarify the precise elements of LA-TDS that can improve T-CPR performance.

Mobile Integrated Health Care in Los Angeles: Upstream Solutions to Mitigate the Covid-19 Pandemic

Innovative collaborations between a 911 emergency medical service (EMS) and local health care leaders helped foster a prehospital Mobile Integrated Health Care strategy that enhanced patient care while also mitigating the impact of Covid-19. Incorporating novel skill sets, alternate-destination pathways, safe and selective nontransport policies, and telehealth into upstream care has helped divert low-acuity patients from hospital EDs and optimally match patient need to location of care. In the City of Los Angeles, these strategies bought time for hospitals to stage for a patient surge, while the EMS bureau created the first Covid-19 testing sites for health care workers and, eventually, the public at large. Challenges such as cost, the need for increased medical oversight, EMS mission creep, and integrating this comprehensive EMS response into the community’s health care system have led to broader discussions with health care executives about unlocking the upstream value of prehospital patient navigation.

Emergency Medical Services Utilization by Homeless Patients

BACKGROUND

Homelessness is a rapidly growing issue throughout the United States and has important public health implications. Los Angeles, like other large urban cities, has seen a recent increase in homelessness. However, little is known about emergency medical service (EMS) utilization by those experiencing homelessness. Objective: Describe the utilization of emergency medical services by homeless patients. Methods: This is a 12-month retrospective review of electronic health records of all 911-incidents attended by the Los Angeles Fire Department (LAFD) from January to December 2018. The City of Los Angeles is 480 square miles and has a population of 3,949,776 with a homeless population of 31,285 (0.8% of city population). The primary outcome is the frequency of EMS 911-calls for homeless patients. Secondary outcomes include call characteristics. Results: There were 355,411 911-incidents during the study period. Homeless patients were involved in 36,122 (10.2%) incidents. Incidents for the homeless population occurred at a rate of 1155 per 1000 homeless residents or 14 times the rate of housed residents. Of the 217,972 calls resulting in transport to the emergency department, 28,917 (13.3%) were for homeless patients. This translates into a rate of 924 per 1000 homeless patients, which is 19 times higher than housed patients. Homeless patients were younger (mean 46.1 v 52.6 years) and more likely to be male (71% v 49.1%). Acuity was lower in the homeless group, 31.4% v 42.5% received advanced life support. Conclusion: In the City of Los Angeles, people experiencing homelessness demonstrated disproportionately high use of EMS services and ambulance transports, were more frequently younger, male, and had lower acuity conditions when compared with housed patients.

Impact of a New 9-1-1 Dispatch System on Call-Processing Times for Time-Critical Emergencies in the City of Los Angeles

Objective: To determine the impact of a new emergency medical services (EMS) 9-1-1 dispatch system on call-processing times for field-confirmed time-critical emergencies. Methods: An interrupted time series study compared 9-1-1 calls for field-confirmed emergencies processed by Los Angeles Fire Department (LAFD)-telecommunicators using either the Medical Priority Dispatch System® (January 1 - September 30, 2014) or the new Los Angeles Tiered Dispatch System (January 1 - September 30, 2015). Prior to the study, authors identified seven categories of time-critical emergencies. Cases meeting inclusion criteria were systematically identified using LAFD electronic health records, and the elapsed time from call receipt to key events were obtained. The primary outcome was call-processing time (CPT), defined as time from 9-1-1 call receipt to when resources were dispatched. Results: During the study period, 12,439 incidents met inclusion criteria: 6,208 using MPDS and 6,231 using LA-TDS. Among all unique time-critical incidents, the mean CPT was 16 seconds faster using LA-TDS (M = 68.5) compared to MPDS (M = 84.4; p < 0.001). CPT was significantly (p < 0.01) lower using LA-TDS for: cardiac arrests with attempted resuscitation, patients requiring ventilation support, seizures requiring prehospital benzodiazepines, gunshot wounds with hypotension, automobile vs. pedestrian accidents, and long falls. There was no difference in CPT for drownings requiring resuscitation (p = 0.60). The elapsed time to arrival of first responders on scene improved from 370.1 seconds using MPDS to 354.8 seconds using LA-TDS (p < 0.001). Conclusion: The new Los Angeles Tiered Dispatch System significantly improved 9-1-1 call-processing times and total response times for nearly all identified time-critical emergencies under study.

Advanced Practice Providers in the Field: Implementation of the Los Angeles Fire Department Advanced Provider Response Unit

Background: To address the growing number of low-acuity patients in the 911-EMS system, the Los Angeles Fire Department (LAFD) launched a pilot program placing an Advanced Provider Response Unit (APRU) in the field so that a prehospital nurse practitioner (NP) could offer patients treatment/release on scene, alternative destination transport, and linkage with social services. Objective: To describe the initial 18-month experience implementing this new APRU. Methods: This is a retrospective, descriptive review of all APRU-attended patients from January 2016 to June 2017. The APRU was an ambulance staffed by an NP and a firefighter/paramedic, equipped with basic point-of-care testing capability, and linked to incidents by either being summoned by on-scene first responders or by monitoring EMS radio traffic. Descriptive statistics were used and outcome measures included counts of clients attended, treat/release rates, impact on total time in service for other LAFD resources, patient need for subsequent re-use of 911 and self-reported experience of care. Results: During its first 18 months in service, the APRU attended 812 patients, including 792 911-patient incidents. 400 of these 911-patients (50.5%) were treated and released on scene or medically cleared and transported to an alternative site for specialty care. This included 76 patients with primary psychiatric complaints who were medically-cleared and transported directly to a mental health urgent care center. An additional 18 high utilizers of 911 were attended by the APRU and connected with a social work organization, and 12 of 18 (66.7%) decreased their use of EMS in the 90-days following APRU evaluation and referral. Of the 400 911-patients that did not go to the emergency department (ED), 26 (6.5%) re-contacted 911 within 3 days: all were transported to the ED with normal vital signs and without prehospital intervention, and all were ultimately discharged home from the ED. As a result of APRU intervention, 458 other LAFD field resources were quickly placed back in service and made available for the next time-critical call. Conclusions: Advanced practice providers such as nurse practitioners can be incorporated into the prehospital setting to address a growing subset of 911-patients whose needs can be met outside of the ED.

Safety of Tiered-Dispatch for 911 Calls for Abdominal Pain

Introduction

Many dispatch systems send Advanced Life Support (ALS) resources to patients complaining of abdominal pain even though the majority of these incidents require only Basic Life Support (BLS). With increasing 911-call volume, resource utilization has become more important to ensure that ALS resources are available for time-critical emergencies. In 2015, a large, urban fire department implemented an internally developed, tiered-dispatch system. Under this system, patients reporting a chief complaint of abdominal pain received the closest BLS ambulance dispatched alone emergency if located within three miles of the incident. The objective of this study was to determine the safety of BLS-only dispatch to abdominal pain by determining the frequency of time-sensitive events.

Methods

This was a retrospective review of electronic health records of one emergency medical service provider agency from May 2015–2018. Inclusion criteria were a chief complaint of abdominal pain from a first- or second-party caller, age over 15, and the patient was reported to be alert and breathing normally. The primary outcome was the prevalence of time-sensitive events, including cardiopulmonary resuscitation (CPR), defibrillation, or airway management. Secondary outcomes were hypotension (systolic blood pressure < 90 mmHg); or a prehospital 12 lead-electrocardiogram (ECG) demonstrating ST-elevation myocardial infarction (STEMI) criteria or a wide complex arrhythmia. Descriptive statistics were used.

Results

During the study period, there were 1,220,820 EMS incidents, of which 33,267 (2.72%) met inclusion criteria. The mean age was 49.9 years (range 16–111, standard deviation [SD] 19.6); 14,556 patients (56.2%) were female. Time-sensitive events occurred in seven cases (0.021%), mean age was 75.3 years (range 30–86, SD18.7); 85.7% were female. Airway management was required in seven cases (0.021%), CPR in six cases (0.018%), and defibrillation in one case (0.003%). Two of the seven (28.6%) cases involved dispatch protocol deviations. Hypotension was present in 240 (0.72%) cases; six (0.018%) cases had 12-lead ECGs meeting STEMI criteria; and no cases demonstrated wide complex arrhythmia.

Conclusion

Among adult 911 patients with a dispatch chief complaint of abdominal pain, time-sensitive events were exceedingly rare. Dispatching a BLS ambulance alone appears to be safe.

Prime the Line! A Case Report of Air Embolism from a Peripheral IV Line in the Field

Venous air embolisms are rare but a cause of potentially life-threatening events with associated cardiovascular, pulmonary and neurologic effects. We report the first prehospital case of a venous air embolism in a 31-year-old male who became hemodynamically unstable after a peripheral intravenous catheter with unprimed tubing was placed by paramedics in the prehospital setting and diagnosed in the emergency department. We highlight the clinical presentation, diagnosis and emergency management of venous air embolisms.

The Digital EMS California Academy of Learning: One State's Innovative Approach to EMS Fellow Education

INTRODUCTION

Emergency medical services (EMS) fellowships are growing in significance within the United States prehospital health care system. While fellowships represent a cornerstone of EMS subspecialty education, an individual learner's experiences are limited by local resources and practices. California EMS fellowships have developed an innovative method for expanding fellows' educational experiences outside their immediate programs.

THE INNOVATIVE EDUCATION METHOD

Each month, fellows, fellowship directors, and local EMS medical directors from throughout the state participate in a video conference. This meeting is divided into four distinct components: book chapter presentation, board-style question review, call review, and an EMS literature review.

CHAPTER REVIEW

The two-volume text Emergency Medical Services: Clinical Practice and Systems Oversight has been categorized into 12 modules, one for each month of the fellowship. Every meeting, one fellow prepares a didactic presentation summarizing the highlights from that month's chapters.

QUESTION REVIEW

Fellows each create five multiple-choice questions and answers, based on the section reading. Questions are assessed by the group, both for informational content and for appropriate formatting. After completion, these questions are submitted for future review for the EMS fellowship in-service examination.

CALL REVIEW

Based on that month's module topics, a call is chosen and reviewed. Regional protocol and practice differences from different systems are discussed. The online medical oversight provided and the prehospital provider performance are evaluated by the group.

LITERATURE REVIEW

Fellows not assigned to present a call or didactic segment each choose one paper focusing on a subject relevant to the module or call. Strengths of the study design, analysis, outcomes, and relevance to EMS practice are discussed.

OUTCOMES

Fellows and experienced EMS attendings are exposed to different protocol and system approaches in an interactive and accessible format. This partnership expands educational opportunities for fellows and promotes collaboration across EMS systems.

The Critical Role of Dispatch

There are 240 million 9-1-1 calls in the United States every year. The burden of managing these emergencies until first responders can arrive is on the dispatchers working in the 5806 public safety answering points, more commonly known as dispatch centers. They are the first link in the chain of survival between the public and the remainder of the health care system. Dispatchers play a critical role in the early identification of emergencies, assignment of appropriate emergency resources, and provision of life-sustaining interventions like dispatcher-assisted cardiopulmonary resuscitation and disaster management.

Abstract WP223: Accelerating Growth in Medicare Beneficiary US Population Served by Mobile Stroke Units During Early Pilot Years (2014-2017)

Background: Mobile Stroke Units (MSUs, mobile CT ambulances) are a new platform for accelerated delivery of proven, time-dependent therapies for acute ischemic and hemorrhagic stroke, undergoing systematic evaluation to determine cost-effectiveness. Formal analysis of the reach of MSU programs in the US during the early pilot period has not previously been undertaken.

Methods: We identified all US MSU programs, active or expected to be active by the end of 2017, via the PRESTO consortium, program leader referrals, vehicle and scanner manufacturer informants, and press release search. MSU access was calculated using geospatial mapping of each vehicle and its surrounding 10 mile radius catchment area, for: 1) population aged ≥ 65, using US Census Bureau county-level values for land area, population density, and proportion of population ≥ 65; and 2) strokes in CMS beneficiaries, using CDC/CMS county-level values for annual stroke hospitalizations.

Results: During the 4 year study period, the number of active MSUs grew from 1 in 2014, 2 in 2015, 6 in 2016, to 13 in 2017, all operating in distinct counties, including 7 (54%) in Census-defined large central metros with high population density, 3 (23%) in large fringe metros with moderately high population density, 3 (23%) in medium/small metros with moderate population density, and 0 (0%) in rural areas. The population over age 65 with MSU access increased from 153,860 in 2014, 315,884 in 2015, 671,960 in 2016, to 1,495,896 in 2017. The number of annual CMS stroke hospitalizations in MSU-covered regions increased from 1,831 in 2014, 3,775 in 2015, 7,031 in 2016, to 15,566 in 2017. By the end of 2017, MSUs were positioned to provide service to 2.9% of all Medicare beneficiaries experiencing stroke hospitalization in the US.

Conclusions: In the short span of the first 4 years of MSU pilot programs in the United States, with only 13 vehicles in service, expanding MSU programs provide access to accelerated treatment for 3 of every 100 US Medicare beneficiaries. This early geomapping analysis indicates that, if demonstration projects confirm cost-effectiveness, supporting wider dissemination, MSU care could provide rapid therapy to a substantial proportion of older Americans with acute ischemic and hemorrhagic stroke.

Interfacility Transports Utilizing the 9-1-1 Emergency Medical Services System

BACKGROUND

With the increasing development of regional specialty centers, emergency physicians are often confronted with patients needing definitive care unavailable at their hospital. Interfacility transports (IFTs) may be a useful option to ensure timely, definitive patient care. However, since traditional IFT can be a challenging and time-consuming process, some EMS agencies that have previously limited their service to 9-1-1 emergency responses are now performing emergency IFTs.

OBJECTIVE

We sought to determine the frequency and nature of transfers provided by a local fire-based 9-1-1 EMS agency that recently began to provide limited IFT for time-critical emergencies.

METHODS

A retrospective review of paramedic reports for all IFTs between April 2007 and March 2014 in the City of Los Angeles, California. All IFTs initiated by 9-1-1 call from an emergency department (ED) and performed by Los Angeles Fire Department paramedics were included. Reason for transfer, patient demographics, and key time metrics were captured.

RESULTS

There were 919 IFTs during the study period, out of approximately 1,160,000 total ambulance transports (0.1%). The most frequent reason for IFT request was for transport of patients with ST segment elevation MI (STEMI) to a STEMI receiving center, followed by major trauma to a trauma center, and intracranial hemorrhage to a center with neurosurgical capability. Less common reasons included vascular emergencies, acute stroke, obstetric emergencies, and transfers to pediatric critical care facilities. Median transport time was 8 minutes (IQR 6-13 minutes) and median total time for IFT was 51 minutes (IQR 39-69 minutes). All IFTs involved a potentially life-threatening condition requiring a higher level of care than was available at the referring hospital.

CONCLUSIONS

Emergent ED-to-ED interfacility transport can provide access to time critical definitive care. EMS agencies that have limited the scope of their response to community 9-1-1 emergencies should have policies in place to assure timely response for emergent IFT requests.