Outcomes of Basic Versus Advanced Life Support for Out-of-Hospital Medical Emergencies

"Dead or Alive?" Assessment of the Binary End-of-Event Outcome Indicator for the NEMSIS Public Research Dataset

OBJECTIVES

The National Emergency Medical Services Information System (NEMSIS) provides a robust set of data to evaluate prehospital care. However, a major limitation is that the vast majority of the records lack a definitive outcome. This study aimed to evaluate the performance of a recently proposed method ("MLB" method) to impute missing end-of-EMS-event outcomes ("dead" or "alive") for patient care reports in the NEMSIS public research dataset.

METHODS

This study reproduced the recently published method for patient outcome imputation in the NEMSIS database and replicated the results for years 2017 through 2022 (n = 686,075). We performed statistical analyses leveraging an array of established performance metrics for binary classification from the machine learning literature. Evaluation metrics included overall accuracy, true positive rate, true negative rate, balanced accuracy, precision, F1 score, Cohen's Kappa coefficient, Matthews' coefficient, Hamming loss, the Jaccard similarity score, and the receiver operating characteristic/area under the curve.

RESULTS

Extended metrics show consistently good imputation performance from year-to-year but reveal weakness in accurately indicating the minority class: e.g., after adjustments for conflicting labels, "dead" prediction accuracy is 77.7% for 2018 and 61.8% over the six-year NEMSIS sub-sample, even though overall accuracy is 98.8%. Slight over-fitting is also present.

CONCLUSIONS

This study found that the recently published MLB method produced reasonably good "dead" or "alive" indicators. We recommend reporting of True Positive Rate ("dead" prediction accuracy) and True Negative Rate ("alive" prediction accuracy) when applying the imputation method for analyses of NEMSIS data. More attention by EMS clinicians to complete documentation of target NEMSIS elements can further improve the method's performance.

Advanced Life Support vs. Basic Life Support for Patients With Trauma in Prehospital Settings: A Systematic Review and Meta-Analysis

Background: Advanced Life Support (ALS) is regarded to be associated with improved survival in pre-hospital trauma care when compared to Basic Life Support (BLS) irrespective of lack of evidence. The aim of this study is to ascertain ALS improves survival for trauma in prehospital settings when compared to BLS.

Methods: We searched PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials for published controlled trials (CTs), and observational studies that were published until Aug 2017. The population of interest were adults (>18 years old) trauma patients who were transported by ground transportation and required resuscitation in prehospital settings. We compared outcomes between the ALS and BLS groups. The primary outcome was in-hospital mortality and secondary outcomes were neurological outcome and time spent on scene.

Results: We identified 2,502 studies from various databases and 10 studies were included in the analysis (two CTs, and eight observational studies). The outcomes were not statistically significant between the ALS and BLS groups (pooled OR 1.14; 95% CI 0.95 to 1.36 for mortality, pooled OR 1.12; 95% CI 0.88 to 1.42 for good neurological outcomes, pooled mean difference −0.96; 95% CI−6.64 to 4.72 for on-scene time) in CTs. In observational studies, ALS prolonged on-scene time and increased mortality (pooled OR 1.56; 95% CI: 1.31 to 1.86 for mortality, and pooled mean difference, 1.26; 95% CI: 0.07 to 2.45 for on-scene time).

Conclusions: In prehospital settings, the present study showed no advantages of ALS on the outcomes in patients with trauma compared to BLS.

The use of resuscitative endovascular balloon occlusion of the aorta (REBOA) for non-traumatic cardiac arrest: A review

Resuscitative endovascular balloon occlusion of the aorta (REBOA) has been proposed as a novel approach to managing non-traumatic cardiac arrest (NTCA). During cardiac arrest, cardiac output ceases and perfusion of vital organs is compromised. Traditional advanced cardiac life support (ACLS) measures and cardiopulmonary resuscitation are often unable to achieve return of spontaneous circulation (ROSC). During insertion of REBOA a balloon-tipped catheter is placed into the femoral artery and advanced in a retrograde manner into the aorta while the patient is undergoing cardiopulmonary resuscitation (CPR). The balloon is then inflated to fully occlude the aorta. The literature surrounding the use of aortic occlusion in non-traumatic cardiac arrest is limited to animal studies, case reports and one recent non-controlled feasibility trial. In both human and animal studies, preliminary data show that REBOA may improve coronary and cerebral perfusion pressures and key physiologic parameters during cardiac arrest resuscitation, and animal data have demonstrated improved rates of ROSC. Multiple questions remain before REBOA can be considered as an adjunct to ACLS. If demonstrated to be effective clinically, REBOA represents a potentially cost-effective and generalizable intervention that may improve quality of life for patients with non-traumatic cardiac arrest.

Health system factors associated with post-trauma mortality at the prehospital care level in Africa: a scoping review

BACKGROUND

Africa accounts forabout 90% of the global trauma burden. Mapping evidence on health systemfactors associated with post-trauma mortality is essential in definingpre-hospital care research priorities and mitigation of the burden. The studyaimed to map and synthesize existing evidence and research gaps on healthsystem factors associated with post-trauma mortality at the pre-hospital carelevel in Africa.

METHODS

A scoping review of published studies and grey literature was conducted. The search strategy utilized electronic databases comprising of Medline, Google Scholar, Pub-Med, Hinari and Cochrane Library. Screening and extraction of eligible studies was done independently and in duplicate.

RESULTS

A total of 782 study titles and or abstracts were screened. Of these, 32 underwent full text review. Out of the 32, 17 met the inclusion criteria for final review. The majority of studies were literature reviews (24%) and retrospective studies (23%). Retrospective and qualitative studies comprised 6% of the included studies, systematic reviews (6%), cross-sectional studies (17%), Delphi studies (6%), panel reviews (6%) and qualitative studies (12%), systematic reviews (6%), cross-sectional studies (17%), Delphi studies (6%), panel reviews (6%) and qualitative studies (12%). Reported post-trauma mortality ranged from 13% in Ghana to 40% in Nigeria. Reported preventable mortality is as high as 70% in South Africa, 60% in Ghana and 40% in Nigeria. Transport mode is the most studied health system factor (reported in 76% of the papers). Only two studies (12%) included access to pre-hospital care interventions aspects, nine studies (53%) included care providers aspects and three studies (18%) included aspects of referral pathways. The types of transport mode and referral pathway are the only factors significantly associated with post-trauma mortality, though the findings were mixed. None of the included studies reported significant associations between pre-hospital care interventions, care providers and post-trauma mortality.

DISCUSSION

Although research on health system factors and its influence on post-trauma mortality at the pre-hospital care level in Africa are limited, anecdotal evidence suggests that access to pre-hospital care interventions, the level of provider skills and referral pathways are important determinants of mortality outcomes. The strength of their influence will require well designed studies that could incorporate mixed method approaches. Moreover, similar reviews incorporating other LMICs are also warranted. Key Words: Health System Factors, Emergency Medical Services [EMS], Pre-hospital Care, Post-Trauma mortality, Africa.

Mistriaged Advanced Life Support Patients in a Two-Tiered, Suburban Emergency Medical Services System

Introduction

Emergency medical services (EMS) systems exist to provide prehospital care in diverse environments throughout the world. Advanced Life Support (ALS) services can provide advanced care including 12-lead electrocardiogram (ECG), endotracheal intubation and parenteral medication administration. Basic Life Support (BLS) can provide basic care such as splinting, wound care and cardiopulmonary resuscitation. ALS can release patients to BLS for transport to the hospital, and this is an area of high risk. Our study examines patients who were triaged and admitted to a critical care location, including an intensive care unit (ICU), cardiac catheterization laboratory, or operating room (OR).

Methods

The analysis included data from 2007–2015 of all patients who were triaged. We evaluated demographics, admission diagnoses, and dispositions using descriptive statistics. Diagnoses were grouped into categories based on the system.

Results

We found that 372/17,639 (2%) of patients were mistriaged to BLS and admitted to a critical care location. The average age was 64. The most common diagnosis categories were neurological (24%), gastrointestinal (GI)/abdominal pain (15%), respiratory (12%), and cardiac (12%).

Conclusion

It is uncommon for patients triaged from ALS to BLS to be admitted to an ICU, catheterization lab or OR, with a rate of 2%. Neurological, GI, respiratory, and cardiac diagnoses were the most frequent categories of patient complaints that were mistriaged. This study should lead to further studies to examine this patient population.

The care and transport of trauma victims by layperson emergency medical systems: a qualitative study in Delhi, India

INTRODUCTION

Ambulance-based emergency medical systems (EMS) are expensive and remain rare in low- and middle-income countries, where trauma victims are usually transported to hospital by passing vehicles. Recent developments in transportation network technologies could potentially disrupt this status quo by allowing coordinated emergency response from layperson networks. We sought to understand the barriers to bystander assistance for trauma victims in Delhi, India, and implications for a layperson-EMS.

METHODS

We used qualitative methods to analyse data from 50 interviews with frontline stakeholders (including taxi drivers, medical professionals, legal experts and police), one stakeholder consultation and a review of documents.

RESULTS

Respondents noted that most trauma victims in Delhi are rapidly brought to hospital by bystanders, taxis and police. While ambulances are common, they are primarily used for interfacility transfers. Entrenched medico-legal practices result in substantial police presence at the hospital, which is a major source of harassment of good Samaritans and interferes with patient care. Trauma victims are often turned away by for-profit hospitals due to their inability to pay, leading to delays in treatment. Recent policy efforts to circumscribe the role of police and force for-profit hospitals to stabilise patients appear to have been unsuccessful.

CONCLUSIONS

Existing healthcare and medico-legal practices in India create large systemic impediments to improving trauma outcomes. Until India's ongoing health and transport sector reforms succeed in ensuring that for-profit hospitals reliably provide care, good Samaritans and layperson-EMS providers should take victims with uncertain financial means to public facilities. To avoid difficulties with police, providers of a layperson-EMS would likely need official police sanction and carry visible symbols of their authority to provide emergency transport. Delhi already has several key components of an EMS (including dispatcher coordinated police response, large ambulance fleet) that could be integrated and expanded into a complete system of emergency care.

Going to the nearest hospital vs. designated trauma centre for road traffic crashes: estimating the time difference in Delhi, India

Background: Time to hospital after a road traffic crash (RTC) plays a vital role in determining the outcome for crash victims. In Delhi, there are seven designated trauma centres where crash victims are typically taken, which may not be nearest hospital. We compare the transport time access (crash to hospital) depending on whether the victim is transported to a designated trauma centre or the nearest hospital. Data and methods: For each RTC geocoded manually from police records, the nearest hospital and the designated trauma centre is identified using Google Maps places nearby Search API and guidelines. Travel time matrix is generated between RTC's and identified hospitals using Google maps distance matrix API. Index accounting inter-district differences is developed. Results and conclusions: The network of designated trauma centres in New Delhi is located such that they can be accessed within 45 min of most crashes while nearest hospital within 30 min. As a result, the vast majority of crash victims are likely to receive timely care if they are rapidly transferred to either of these caregivers. However, for the most severely injured and time-sensitive cases, bypassing nearest hospital for trauma care, could substantially improve survival outcomes.

Collecting core data in physician-staffed pre-hospital helicopter emergency medical services using a consensus-based template: international multicentre feasibility study in Finland and Norway

BACKGROUND

Comparison of services and identification of factors important for favourable patient outcomes in emergency medical services (EMS) is challenging due to different organization and quality of data. The purpose of the present study was to evaluate the feasibility of physician-staffed EMS (p-EMS) to collect patient and system level data by using a consensus-based template.

METHODS

The study was an international multicentre observational study. Data were collected according to a template for uniform reporting of data from p-EMS using two different data collection methods; a standard and a focused data collection method. For the standard data collection, data were extracted retrospectively for one year from all FinnHEMS bases and for the focused data collection, data were collected prospectively for six weeks from four selected Norwegian p-EMS bases. Completeness rates for the two data collection methods were then compared and factors affecting completeness rates and template feasibility were evaluated. Standard Chi-Square, Fisher's Exact Test and Mann-Whitney U Test were used for group comparison of categorical and continuous data, respectively, and Kolomogorov-Smirnov test for comparison of distributional properties.

RESULTS

All missions with patient encounters were included, leaving 4437 Finnish and 128 Norwegian missions eligible for analysis. Variable completeness rates indicated that physiological variables were least documented. Information on pain and respiratory rate were the most frequently missing variables with a standard data collection method and systolic blood pressure was the most missing variable with a focused data collection method. Completeness rates were similar or higher when patients were considered severely ill or injured but were lower for missions with short patient encounter. When a focused data collection method was used, completeness rates were higher compared to a standard data collection method.

CONCLUSIONS

We found that a focused data collection method increased data capture compared to a standard data collection method. The concept of using a template for documentation of p-EMS data is feasible in physician-staffed services in Finland and Norway. The greatest deficiencies in completeness rates were evident for physiological parameters. Short missions were associated with lower completeness rates whereas severe illness or injury did not result in reduced data capture.

Time to epinephrine and survival after paediatric out-of-hospital cardiac arrest

Aims

Delay in administration of epinephrine is associated with decreased survival among children with in-hospital cardiac arrest with an initial non-shockable rhythm. Whether this association is applicable to paediatric out-of-hospital cardiac arrest (OHCA) population remains unknown. We aimed to determine whether time to epinephrine administration is associated with outcomes in paediatric OHCA.

Methods and results

This was a nation-wide population-based study of paediatric OHCA in Japan from 2005 to 2012 based on data from the All-Japan Utstein Registry. We included paediatric OHCA patients (aged between 1 and 17 years) who received at least one dose of epinephrine. The primary outcome was 30-day survival. A total of 225 patients were included in the final cohort. Among the 225 patients, 23 (10.2%) survived 30 days after OHCA. The median time from emergency call to first epinephrine administration was 26 min [interquartile range, 20-32; range, 9-128; mean (standard deviation), 28.7 (15.5) min]. Longer time to epinephrine administration was associated with decreased chance of survival: 50.0, 41.2, 13.0, 11.6, 3.9, and 3.1%, respectively, when time to epinephrine was treated as a categorical variable categorized into ≤10, 11-15, 16-20, 21-25, 26-30, or > 30 min (P for trend <0.0001), and adjusted odds ratio 0.90 (95% confidence interval 0.82-0.96, P = 0.0011) when time to epinephrine was treated as a linear and continuous variable in a multivariable logistic regression model. Similar trends were observed for prehospital return of spontaneous circulation (P = 0.0032) and neurologically favourable survival (P = 0.0014).

Conclusions

Among paediatric OHCA patients, delayed administration of epinephrine was associated with a decreased chance of favourable outcomes.

Theoretical knowledge and psychomotor skill acquisition of basic life support training programme among secondary school students

BACKGROUND

The aim of the study is to evaluate the theoretical knowledge and psychomotor skill acquisition of basic life support (BLS) by a group of secondary school students in Nigeria pre and post BLS training.

METHODS

This was quasi-experimental study design with 210 participants. They were taught on adult BLS and all the participants practiced BLS on a Resusci-Anne manikin immediately after the training. Data were collected using American Heart Association (AHA) structured questionnaire and psychomotor skills checklist for BLS at baseline, and post BLS training.

RESULTS

The pre-training knowledge score was 1.9±1.4. This increased after the BLS training to 11.4±2.4, and the mean difference between the pre and post BLS training scores was 9.48571. Pre-training psychomotor skill score was 0.00±0.00, this increased to 8.9±1.9 after the training, and the mean difference was 8.90000. The knowledge and psychomotor skill difference between pre and post BLS training was significant (P<0.000).CONCLUSION: Most Nigerian secondary school students were not knowledgeable about BLS. Therefore, there is need for the creation of more awareness among the students.

Prehospital Care and Emergency Department Door-to-Antibiotic Time in Sepsis

RATIONALE

Early antibiotics improve outcomes for patients with sepsis. Factors influencing antibiotic timing in emergency department (ED) sepsis remain unclear.

OBJECTIVES

Determine the relationship between prehospital level of care of patients with sepsis and ED door-to-antibiotic time.

METHODS

This retrospective cohort study comprised patients admitted from the community to an academic ED June 2009 to February 2015 with fluid-refractory sepsis or septic shock. Transfer patients and those whose antibiotics began before ED arrival or after ED discharge were excluded. We used multivariable regression to evaluate the association between the time from ED arrival to antibiotic initiation and prehospital level of care, defined as the highest level of emergency medical services received: none, basic life support (BLS) ambulance, or advanced life support (ALS) ambulance. We measured variation in this association when hypotension was or was not present by ED arrival.

RESULTS

Among 361 community-dwelling patients with sepsis, the level of prehospital care correlated with illness severity. ALS-treated patients received antibiotics faster than patients who did not receive prehospital care (median, 103 [interquartile range, 75 to 135] vs. 144 [98 to 251] minutes, respectively) or BLS-only patients (168 [100-250] minutes; P < 0.001 for each pairwise comparison with ALS). This pattern persisted after multivariable adjustment, where ALS care (-43 min; 95% confidence interval [CI], -84 to -2; P = 0.033) but not BLS-only care (-4 min; 95% CI, -41 to +34; P = 0.97) was associated with less antibiotic delay compared with no prehospital care. ALS-treated patients more frequently received antibiotics within 3 hours of ED arrival (91%) compared with walk-in patients (62%; adjusted odds ratio, 3.11; 95% CI, 1.20 to 8.03; P = 0.015) or BLS-treated patients (56%; adjusted odds ratio, 4.51; 95% CI, 1.89 to 11.35; P < 0.001). ALS-treated patients started antibiotics faster than walk-in patients in the absence of hypotension by ED arrival (-41 min; 95% CI, -110 to -13; P = 0.009) but not when hypotension was present (+25 min; 95% CI, -43 to +92; P = 0.66).

CONCLUSIONS

Prehospital ALS but not BLS-only care was associated with faster antibiotic initiation for patients with sepsis without hypotension. Process redesign for non-ALS patients may improve antibiotic timeliness for ED sepsis.

Gender Disparities in Out-of-hospital Cardiac Arrests

Background

Despite advances in resuscitation science and public health, out-of-hospital cardiac arrest (OOHCA) has an average survival rate of only 12% nationwide, compared to 24.8% of patients who suffer from cardiac arrest while in hospital. Additionally, gender is an important element of human health, and there is a clear pattern for gender-specific survivability in cardiac arrest. This study examined differences in presentations, treatment, management, and outcomes.

Aim

The primary focus of this study was to shed light on differences in presentations, treatments, and outcomes between men and women suffering from an out-of-hospital cardiac arrest and the accompanying contributing factors.

Methods

All emergency medical services-related data, including age, date, initial rhythm, chemical interventions (i.e., epinephrine, dextrose), blood glucose levels, defibrillations, endotracheal tube (ETT) attempts, final airway management, achievement of return of spontaneous circulation (ROSC), and the conclusion of the case up to the emergency department, were recorded using a standardized emergency medical services (EMS) charting record by the highest-ranking EMS provider on the ambulance. The reports were retrospectively collected and analyzed.

Conclusion

The study examined demographics, treatments rendered, and outcomes in OOHCA cases that occurred in a major United States (US) city in 2016. Several significant differences in care were noted between men and women. In general, women received less respiratory, chemical, and electrical interventions than men; however, statistically significant differences were only observed in the number of attempts of endotracheal intubations, number of doses of epinephrine per encounter, and number of defibrillations per encounter. In spite of generally receiving less care, women appeared to respond more favorably to cardiac arrest interventions, as demonstrated by higher rates of ROSC. Despite this, women were also found to be eight years older at the time of arrest. Future studies are needed to determine causality in discrepancies between the genders in addition to investigating differences in treatment in other areas of the United States.

Association of Prehospital Advanced Life Support by Physician With Survival After Out-of-Hospital Cardiac Arrest With Blunt Trauma Following Traffic Collisions: Japanese Registry-Based Study

Importance

Controversy remains as to whether advanced life support (ALS) or basic life support (BLS) is superior for critically ill and injured patients, including out-of-hospital cardiac arrest (OHCA) and major trauma, in the prehospital setting.

Objective

To assess whether prehospital ALS should be provided for traumatic OHCA and who should perform it.

Design, Setting, and Participants

Japanese government-managed nationwide population-based registry data of patients with OHCA transported to an emergency hospital were analyzed. Patients who experienced traumatic OHCA following a traffic collision from 2013 to 2014 were included. Patients provided prehospital ALS by a physician were compared with both patients provided ALS by emergency medical service (EMS) personnel and patients with only BLS. The data were analyzed on May 1, 2017.

Exposures

Advanced life support by physician, ALS by EMS personnel, or BLS only.

Main Outcomes and Measures

The primary outcome was 1-month survival. The secondary outcomes were prehospital return of spontaneous circulation and favorable neurologic outcomes with the Glasgow-Pittsburgh cerebral performance category score of 1 or 2.

Results

A total of 4382 patients were included (mean [SD] age, 57.5 [22.2] years; 67.9% male); 828 (18.9%) received prehospital ALS by physician, 1591 (36.3%) received prehospital ALS by EMS personnel, and 1963 (44.8%) received BLS only. Among these patients, 96 (2.2%) survived 1 month after OHCA, including 26 of 828 (3.1%) for ALS by physician, 25 of 1591 (1.6%) for ALS by EMS personnel, and 45 of 1963 (2.3%) for BLS. After adjusting for potential confounders using multivariable logistic regression, ALS by physician was significantly associated with higher odds for 1-month survival compared with both ALS by EMS personnel and BLS (adjusted OR, 2.13; 95% CI, 1.20-3.78; and adjusted OR, 1.94; 95% CI, 1.14-3.25; respectively), whereas there was no significant difference between ALS by EMS personnel and BLS (adjusted OR, 0.91; 95% CI, 0.54-1.51). A propensity score-matched analysis in the ALS cohort showed that ALS by physician was associated with increased chance of 1-month survival compared with ALS by EMS personnel (risk ratio, 2.00; 95% CI, 1.01-3.97; P = .04). This association was consistent across a variety of sensitivity analyses.

Conclusions and Relevance

In traumatic OHCA, ALS by physician was associated with increased chance of 1-month survival compared with both ALS by EMS personnel and BLS.

Prehospital intravenous access for survival from out-of-hospital cardiac arrest: propensity score matched analyses from a population-based cohort study in Osaka, Japan

OBJECTIVES

Prehospital intravenous access is a common intervention for patients with out-of-hospital cardiac arrest (OHCA). We aimed to assess the effectiveness of prehospital intravenous access and subsequent epinephrine administration on outcomes among OHCA patients.

METHODS

We conducted a prospective cohort study of patients with OHCA from non-traumatic causes aged ≥18 years in Osaka, Japan from January 2005 through December 2012. The primary outcome was 1-month survival with favourable neurological outcome defined as a cerebral performance category of 1 or 2. The association between intravenous line placement and survival with favourable neurological outcome was evaluated by logistic regression, after propensity score matching for the intravenous access attempt stratified by initial documented rhythm of ventricular fibrillation (VF) or non-VF. The contribution of epinephrine administration to the outcome was also explored.

RESULTS

Among OHCA patients during the study period, 3208 VF patients and 38 175 non-VF patients were included in our analysis. Intravenous access attempt was negatively associated with 1-month survival with a favourable neurological outcome in VF group (OR 0.76, 95% CI 0.59 to 0.98), while no association was observed in the non-VF group (OR 1.06, 95% CI 0.84 to 1.34). Epinephrine administration had no positive association in the VF patients (OR 0.75, 95% CI 0.51 to 1.07) and positively associated in the non-VF patients (OR 1.52, 95% CI 1.08 to 2.08) with the favourable neurological outcome.

CONCLUSIONS

Intravenous access attempt could be negatively associated with survival with a favourable neurological outcome after OHCA. Subsequent epinephrine administration might be effective for non-VF OHCAs.

A traumatic tale of two cities: does EMS level of care and transportation model affect survival in patients with trauma at level 1 trauma centres in two neighbouring Canadian provinces?

BACKGROUND

Two distinct Emergency Medical Services (EMS) systems exist in Atlantic Canada. Nova Scotia operates an Advanced Emergency Medical System (AEMS) and New Brunswick operates a Basic Emergency Medical System (BEMS). We sought to determine if survival rates differed between the two systems.

METHODS

This study examined patients with trauma who were transported directly to a level 1 trauma centre in New Brunswick or Nova Scotia between 1 April 2011 and 31 March 2013. Data were extracted from the respective provincial trauma registries; the lowest common Injury Severity Score (ISS) collected by both registries was ISS≥13. Survival to hospital and survival to discharge or 30 days were the primary endpoints. A separate analysis was performed on severely injured patients. Hypothesis testing was conducted using Fisher's exact test and the Student's t-test.

RESULTS

101 cases met inclusion criteria in New Brunswick and were compared with 251 cases in Nova Scotia. Overall mortality was low with 93% of patients surviving to hospital and 80% of patients surviving to discharge or 30 days. There was no difference in survival to hospital between the AEMS (232/251, 92%) and BEMS (97/101, 96%; OR 1.98, 95% CI 0.66 to 5.99; p=0.34) groups. Furthermore, when comparing patients with more severe injuries (ISS>24) there was no significant difference in survival (71/80, 89% vs 31/33, 94%; OR 1.96, 95% CI 0.40 to 9.63; p=0.50).

CONCLUSION

Overall survival to hospital was the same between advanced and basic Canadian EMS systems. As numbers included are low, individual case benefit cannot be excluded.

Effect of pre-hospital advanced airway management for out-of-hospital cardiac arrest caused by respiratory disease: a propensity score-matched study

Optimal pre-hospital care for out-of-hospital cardiac arrest (OHCA) caused by respiratory disease may differ from that for OHCA associated with other aetiologies, especially with respect to respiratory management. We aimed to investigate whether pre-hospital advanced airway management (AAM) was associated with favourable outcomes after OHCA caused by intrinsic respiratory disease. This nationwide, population-based, propensity score-matched study of adult patients in Japan with OHCA due to respiratory disease from 1 January 2005 to 31 December 2012 compared patients with and without pre-hospital AAM. The primary outcome was neurologically favourable survival at one month after the OHCA. Of 49,534 eligible patients, 20,458 received pre-hospital AAM and 29,076 did not. In a propensity score-matched cohort (18,483 versus 18,483 patients), the odds of neurologically favourable survival were significantly lower for patients receiving pre-hospital AAM (0.6% versus 1.5%; odds ratio [OR] 0.42 [95% confidence interval {CI} 0.34 to 0.52]). The results from multivariable logistic regression analysis also showed that pre-hospital AAM was significantly associated with a decreased chance of neurologically favourable survival (adjusted OR 0.43 [95% CI 0.35 to 0.52]). Similar findings were observed for one-month survival and pre-hospital return of spontaneous circulation. In subgroup analyses, pre-hospital AAM was associated with poor neurological outcomes, regardless of the type of airway device used (laryngeal mask airway, adjusted OR 0.35 [95% CI 0.19 to 0.57]; oesophageal obturator airway, adjusted OR 0.44 [95% CI 0.35 to 0.55]; and endotracheal tube, adjusted OR 0.47 [95% CI 0.30 to 0.69]). In conclusion, pre-hospital AAM was associated with poor neurological outcome among patients with OHCA caused by intrinsic respiratory disease.

Geographic Variation in Use of Ambulance Transport to the Emergency Department

STUDY OBJECTIVE

Evidence on variability in emergency medical services use is limited. We obtain national evidence on geographic variation in the use of ambulance transport to the emergency department (ED) among Medicare enrollees and assess the role of health status, socioeconomic status, and provider availability.

METHODS

We used 2010 Medicare claims data for a random sample of 999,999 enrollees aged 66 years and older, and identified ambulance transport and ED use. The main outcome measures were number of ambulance transports to the ED per 100 person-years (ambulance transport rate) and proportion (percentage) of ED visits by ambulance transport by hospital referral regions.

RESULTS

The national ambulance transport rate was 22.2 and the overall proportion of ED visits by ambulance was 36.7%. Relative to hospital referral regions in the lowest rate quartile, those in the highest quartile had a 75% higher ambulance transport rate (incidence rate ratio [IRR] 1.75; 95% confidence interval [CI] 1.69 to 1.81) and a 15.5% higher proportion of ED visits by ambulance (IRR 1.155; 95% CI 1.146 to 1.164). Adjusting for health status, socioeconomic status, and provider availability reduced quartile 1 versus quartile 4 difference in ambulance transport rate by 43% (IRR 1.43; 95% CI 1.38 to 1.48) and proportion of ED visits by ambulance by 7% (IRR 1.145; 95% CI 1.135 to 1.155). Among the 3 covariate domains, health status was associated with the largest variability in ambulance transport rate (30.1%), followed by socioeconomic status (12.8%) and provider availability (2.9%).

CONCLUSION

Geographic variability in ambulance use is large and associated with variation in patient health status and socioeconomic status.

Delays in Emergency Care and Mortality during Major U.S. Marathons

BACKGROUND

Large marathons frequently involve widespread road closures and infrastructure disruptions, which may create delays in emergency care for nonparticipants with acute medical conditions who live in proximity to marathon routes.

METHODS

We analyzed Medicare data on hospitalizations for acute myocardial infarction or cardiac arrest among Medicare beneficiaries (≥65 years of age) in 11 U.S. cities that were hosting major marathons during the period from 2002 through 2012 and compared 30-day mortality among the beneficiaries who were hospitalized on the date of a marathon, those who were hospitalized on the same day of the week as the day of the marathon in the 5 weeks before or the 5 weeks after the marathon, and those who were hospitalized on the same day as the marathon but in surrounding ZIP Code areas unaffected by the marathon. We also analyzed data from a national registry of ambulance transports and investigated whether ambulance transports occurring before noon in marathon-affected areas (when road closures are likely) had longer scene-to-hospital transport times than on nonmarathon dates. We also compared transport times on marathon dates with those on nonmarathon dates in these same areas during evenings (when roads were reopened) and in areas unaffected by the marathon.

RESULTS

The daily frequency of hospitalizations was similar on marathon and nonmarathon dates (mean number of hospitalizations per city, 10.6 and 10.5, respectively; P=0.71); the characteristics of the beneficiaries hospitalized on marathon and nonmarathon dates were also similar. Unadjusted 30-day mortality in marathon-affected areas on marathon dates was 28.2% (323 deaths in 1145 hospitalizations) as compared with 24.9% (2757 deaths in 11,074 hospitalizations) on nonmarathon dates (absolute risk difference, 3.3 percentage points; 95% confidence interval, 0.7 to 6.0; P=0.01; relative risk difference, 13.3%). This pattern persisted after adjustment for covariates and in an analysis that included beneficiaries who had five or more chronic medical conditions (a group that is unlikely to be hospitalized because of marathon participation). No significant differences were found with respect to where patients were hospitalized or the treatments they received in the hospital. Ambulance scene-to-hospital transport times for pickups before noon were 4.4 minutes longer on marathon dates than on nonmarathon dates (relative difference, 32.1%; P=0.005). No delays were found in evenings or in marathon-unaffected areas.

CONCLUSIONS

Medicare beneficiaries who were admitted to marathon-affected hospitals with acute myocardial infarction or cardiac arrest on marathon dates had longer ambulance transport times before noon (4.4 minutes longer) and higher 30-day mortality than beneficiaries who were hospitalized on nonmarathon dates. (Funded by the National Institutes of Health.).

Methodological Challenges in Studies Comparing Prehospital Advanced Life Support with Basic Life Support

Determining the most appropriate level of care for patients in the prehospital setting during medical emergencies is essential. A large body of literature suggests that, compared with Basic Life Support (BLS) care, Advanced Life Support (ALS) care is not associated with increased patient survival or decreased mortality. The purpose of this special report is to synthesize the literature to identify common study design and analytic challenges in research studies that examine the effect of ALS, compared to BLS, on patient outcomes. The challenges discussed in this report include: (1) choice of outcome measure; (2) logistic regression modeling of common outcomes; (3) baseline differences between study groups (confounding); (4) inappropriate statistical adjustment; and (5) inclusion of patients who are no longer at risk for the outcome. These challenges may affect the results of studies, and thus, conclusions of studies regarding the effect of level of prehospital care on patient outcomes should require cautious interpretation. Specific alternatives for avoiding these challenges are presented. Li T , Jones CMC , Shah MN , Cushman JT , Jusko TA . Methodological challenges in studies comparing prehospital Advanced Life Support with Basic Life Support. Prehosp Disaster Med. 2017;32(4):444-450.

False Dichotomies and Health Policy Research Designs: Randomized Trials Are Not Always the Answer

Some medical scientists argue that only data from randomized controlled trials (RCTs) are trustworthy. They claim data from natural experiments and administrative data sets are always spurious and cannot be used to evaluate health policies and other population-wide phenomena in the real world. While many acknowledge biases caused by poor study designs, in this article we argue that several valid designs using administrative data can produce strong findings, particularly the interrupted time series (ITS) design. Many policy studies neither permit nor require an RCT for cause-and-effect inference. Framing our arguments using Campbell and Stanley's classic research design monograph, we show that several "quasi-experimental" designs, especially interrupted time series (ITS), can estimate valid effects (or non-effects) of health interventions and policies as diverse as public insurance coverage, speed limits, hospital safety programs, drug abuse regulation and withdrawal of drugs from the market. We further note the recent rapid uptake of ITS and argue for expanded training in quasi-experimental designs in medical and graduate schools and in post-doctoral curricula.

The Effect of Ambulance Staffing Models in a Metropolitan, Fire-Based EMS System

Introduction The staffing of ambulances with different levels of Emergency Medical Service (EMS) providers is a difficult decision with evidence being mixed on the benefit of each model. Hypothesis/Problem The objective of this study was to describe a pilot program evaluating alternative staffing on two ambulances utilizing the paramedic-basic (PB) model (staffed with one paramedic and one emergency medical technician[EMT]).

METHODS

This was a retrospective study conducted from September 17, 2013 through December 31, 2013. The PB ambulances were compared to geographically matched ambulances staffed with paramedic-paramedic (PP ambulances). One PP and one PB ambulance were based at Station A; one PP and one PB ambulance were based at Station B. The primary outcome was total on-scene time. Secondary outcomes included time-to-electrocardiogram (EKG), time-to-intravenous (IV) line insertion, IV-line success rate, and percentage of protocol violations. Inclusion criteria were all patients requesting prehospital services that were attended to by these teams. Patients were excluded if they were not attended to by the study ambulance vehicles. Descriptive statistics were reported as medians and interquartile ranges (IQR). Proportions were reported with 95% confidence intervals (CI). The Mann-Whitley U test was used for significance testing (P<.05).

RESULTS

Median on-scene times at Station A for the PP ambulance were shorter than the PB ambulance team (PP: 10.1 minutes, IQR 6.0-15; PB: 13.0 minutes, IQR 8.1-18; P=.01). This finding also was noted at Station B (PP: 13.5 minutes, IQR 8.5-19; PB: 14.3 minutes, IQR 9.9-20; P=.01). There were no differences between PP and PB ambulance teams at Station A or Station B in time-to-EKG, time-to-IV insertion, IV success rate, and protocol violation rates.

CONCLUSION

In the setting of a well-developed EMS system utilizing an all-Advanced Life Support (ALS) response, this study suggests that PB ambulance teams may function well when compared to PP ambulances. Though longer scene times were observed, differences in time to ALS interventions and protocol violation rates were not different. Hybrid ambulance teams may be an effective staffing alternative, but decisions to use this model must address clinical and operational concerns. Cortez EJ , Panchal AR , Davis JE , Keseg DP . The effect of ambulance staffing models in a metropolitan, fire-based EMS system. Prehosp Disaster Med. 2017;32(2):175-179.