Effects of modifiable prehospital factors on survival after out-of-hospital cardiac arrest in rural versus urban areas

Out-of-hospital cardiac arrest outcomes' determinants: an Italian retrospective cohort study based on Lombardia CARe

This study on the Lombardia Cardiac Arrest Registry (Lombardia CARe,) the most complete nationwide out-of-hospital cardiac arrest (OHCA) registry in Italy, aims at evaluating post-OHCA intra-hospital mortality risk according to patient's characteristics and emergency health service management (EMS), including level of care of first-admission hospital. Out of 12,581 patients included from 2015 to 2022, we considered 1382 OHCA patients admitted alive to hospital and survived more than 24 h. We estimated risk ratios (RRs) of intra-hospital mortality through log-binomial regression models adjusted by patients' and EMS characteristics. The study population consisted mainly of males (66.6%) most aged 60-69 years (24.7%) and 70-79 years (23.7%). Presenting rhythm was non-shockable in 49.9% of patients, EMS intervention time was less than 10 min for 30.3% of patients, and cardiopulmonary resuscitation (CPR) was performed for less than 15 min in 29.9%. Moreover, 61.6% of subjects (n = 852) died during hospital admission. Intra-hospital mortality is associated with non-shockable presenting rhythm (RR 1.27, 95% CI 1.19-1.35) and longer CPR time (RR 1.39, 95% CI 1.28-1.52 for 45 min or more). Patients who accessed to a secondary vs tertiary care hospital were more frequently older, with a non-shockable presenting rhythm and longer EMS intervention time. Non-shockable presenting rhythm accounts for 27% increased risk of intra-hospital death in OHCA patients, independently of first-access hospital level, thus demonstrating that patients' outcomes depend only by intrinsic OHCA characteristics and Health System's resources are utilised as efficiently as possible.

Evaluation of Mortality Rate Disparities for Cardiac Arrest Between Urban and Rural Cohorts in the United States Using the Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research (CDC WONDER) Database

Introduction The United States includes diverse geographic areas with distinct urban and rural settings. Urban areas served with higher health services and the rural regions with restricted facilities. This disparity results in higher rural mortality rates. Thus, the study uses the Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research (CDC WONDER) database to assess the disparities in cardiac arrest mortality rates in urban versus rural areas. Methods This is a retrospective study to assess trends in overall mortality rates for urban versus rural areas in the United States between 1999 and 2020, using the CDC WONDER data for cardiac arrest (ICD-10 CODE I46), extracted on May 25, 2024. Urban/rural classification was based on the Metropolitan 2013 scheme. Statistical analysis was done via RStudio v.4.3.3 and included measures of central tendency, mortality rates per 100,000, and plotting of temporal trends. Results Between 1999 and 2020, the total number of deaths due to cardiac arrest in rural and urban areas was 103,115 and 262,505, respectively. Among the age groups, infants <1 year and elderly >85 years showed a high mortality rate in rural areas compared to urban areas. Gender analysis revealed both males (3.3 per 100,000) and females (3.52 per 100,000) had a high rural mortality rate, compared to urban rates of 1.51 and 1.54 per 100,000, respectively. Racial analysis showed that American Indian or Alaska Native and Asian or Pacific Islander populations had higher mortality in rural areas, with rates of 1.1 and 1.81 per 100,000, respectively, compared to the urban rates of 0.34 and 0.8 per 100,000. Conclusion Trends in mortality rate showed a general decline over time but the gap between urban and rural mortality persists, highlighting the need for continued efforts in rural areas.

Systematic Review on the Worldwide Disparities in the Frequency and Results of Emergency Medical Services (EMS) and Response to Out-of-Hospital Cardiac Arrest (OHCA)

This systematic analysis aimed to analyze the key patterns and tendencies regarding bystander interventions, emergency medical service (EMS) systems, dispatcher support, regional and temporal differences, and the influence of national efforts on survival rates in out-of-hospital cardiac arrest (OHCA). The studies published between 2010 and 2024 examining outcomes of OHCA, interventions by bystanders, and variables linked to OHCA were included in this research. The inclusion process was done under Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), where publications (n = 24) from various geographical locations, including a wide range of research methodologies, were included for this research. The thematic analysis used for the data analysis shows that bystander cardiopulmonary resuscitation (CPR) enhances the chances of survival. The effectiveness of the EMS system, the assistance offered by dispatchers, and the inclusion of doctors in ambulance services are essential components in the management of OHCA. Regional and temporal variations highlight disparities in resuscitation protocols, emphasizing the need for adaptable approaches. Observations from statewide endeavors emphasize the impact of these activities in fostering a culture of prompt bystander intervention. This systematic review presents a comprehensive analysis of research conducted globally, providing a thorough insight into the variables that influence survival rates in instances of OHCA. The review recognizes the importance of bystander CPR and effective EMS services, while also bringing novel perspectives, such as gender disparities and geographical variations that contribute to the existing body of research. Despite possible variances in the studies and biases, the findings underscore the need for tailored therapies and ongoing research to optimize strategies for controlling OHCA and improving survival rates.

Pakistan's Emergency Medical Services (EMS) system & out-of-hospital-cardiac-arrest (OHCA): A narrative review of an EMS system of a low middle income country in context of OHCA

Pakistan's Emergency Medical Services (EMS) are a critical component of its healthcare system, providing pre-hospital emergency care across a nation with over 220 million people. This article explores the evolutionary journey of Pakistan's EMS, highlighting both the challenges it faces and the strides it has made, with a specific emphasis on patients experiencing out-of-hospital cardiac arrest (OHCA). To extract relevant information, we searched MEDLINE & Embase data bases using MeSH terms "Emergency Medical Services" OR "EMS" AND "Out-of-Hospital-Cardiac-Arrest" OR "OHCA" AND "Pakistan". In addition, we also retrieved information from the EMS leadership in Pakistan through e-mails. We delve into the significance of key performance indicators for OHCA, advocate for the establishment of OHCA registries to improve patient outcomes, address regional disparities in pre-hospital care, and acknowledge the gradual progress of the EMS system.

Prediction model for future OHCAs based on geospatial and demographic data: An observational study

This study used demographic data in a novel prediction model to identify areas with high risk of out-of-hospital cardiac arrest (OHCA) in order to target prehospital preparedness. We combined data from the nationwide Danish Cardiac Arrest Registry with geographical- and demographic data on a hectare level. Hectares were classified in a hierarchy according to characteristics and pooled to square kilometers (km2). Historical OHCA incidence of each hectare group was supplemented with a predicted annual risk of at least 1 OHCA to ensure future applicability. We recorded 19,090 valid OHCAs during 2016 to 2019. The mean annual OHCA rate was highest in residential areas with no point of public interest and 100 to 1000 residents per hectare (9.7/year/km2) followed by pedestrian streets with multiple shops (5.8/year/km2), areas with no point of public interest and 50 to 100 residents (5.5/year/km2), and malls with a mean annual incidence per km2 of 4.6. Other high incidence areas were public transport stations, schools and areas without a point of public interest and 10 to 50 residents. These areas combined constitute 1496 km2 annually corresponding to 3.4% of the total area of Denmark and account for 65% of the OHCA incidence. Our prediction model confirms these areas to be of high risk and outperforms simple previous incidence in identifying future risk-sites. Two thirds of out-of-hospital cardiac arrests were identified in only 3.4% of the area of Denmark. This area was easily identified as having multiple residents or having airports, malls, pedestrian shopping streets or schools. This result has important implications for targeted intervention such as automatic defibrillators available to the public. Further, demographic information should be considered when implementing such interventions.

Health inequalities in cardiopulmonary resuscitation and use of automated electrical defibrillators in out-of-hospital cardiac arrest

Out of hospital cardiac arrest (OHCA) outcomes can be improved by strengthening the chain of survival, namely prompt cardiopulmonary resuscitation (CPR) and automated external defibrillator (AED). However, provision of bystander CPR and AED use remains low due to individual patient factors ranging from lack of education to socioeconomic barriers and due to lack of resources such as limited availability of AEDs in the community. Although the impact of health inequalities on survival from OHCA is documented, it is imperative that we identify and implement strategies to improve public health and outcomes from OHCA overall but with a simultaneous emphasis on making care more equitable. Disparities in CPR delivery and AED use in OHCA exist based on factors including sex, education level, socioeconomic status, race and ethnicity, all of which we discuss in this review. Most importantly, we discuss the barriers to AED use, and strategies on how these may be overcome.

Trends of hypertrophic cardiomyopathy-related mortality in United States young adults: a nationwide 20-year analysis

AIMS

Data regarding hypertrophic cardiomyopathy (HCM)-related mortality in United States young adults, defined as those aged between 25 and 44 years, are lacking. We sought to assess the trends in HCM-related mortality among US young adults between 1999 and 2019 and determine differences by sex, race, ethnicity, urbanization and census region.

METHODS

Mortality data were retrieved by the Centers for Disease Control and Prevention (CDC) Wide-Ranging Online Data for Epidemiologic Research (WONDER) dataset from January 1999 to December 2019. Age-adjusted mortality rates (AAMRs) were assessed using the Joinpoint regression modeling and expressed as estimated average annual percentage change (AAPC) with relative 95% confidence intervals (95% CIs).

RESULTS

Over 20-year period, the AAMR from HCM in US young adults linearly decreased, with no differences between sexes [AAPC: -5.3% (95% CI -6.1 to -4.6), P  < 0.001]. The AAMR decrease was more pronounced in Black patients [AAPC: -6.4% (95% CI -7.6 to -5.1), P  < 0.001], Latinx/Hispanic patients [AAPC: -4.8% (95% CI -7.2 to -2.36), P  < 0.001] and residents of urban areas [AAPC: -5.4% (95% CI -6.2 to -4.6), P  < 0.001]. The higher percentages of HCM-related deaths occurred in the South of the country and at the patient's home.

CONCLUSION

HCM-related mortality in US young adults has decreased over the last two decades in the United States. Subgroup analyses by race, ethnicity, urbanization and census region showed ethnoracial and regional disparities that will require further investigation.

Rural cardiac arrest care and outcomes in Texas

INTRODUCTION

Out-of-hospital cardiac arrest (OHCA) victims in rural communities have worse outcomes despite higher rates of bystander cardiopulmonary resuscitation (CPR) than urban communities. In this retrospective cohort study we attempt to evaluate selected aspects of the continuum of care, including post-arrest care, for rural OHCA victims, and we investigated factors that could contribute to rural areas having higher rates of bystander CPR.

METHODS

We analyzed 2014-2020 Texas Cardiac Arrest Registry to Enhance Survival (TX-CARES) data for adult OHCAs. We linked TX-CARES data to census tract data and stratified OHCAs into urban and rural events. We created a mixed-model logistic regression to compare cardiac arrest characteristics, pre-hospital care, and post-arrest care between rural and urban settings. We adjusted for confounders and modeled census tract as a random intercept. We then compared different regression models evaluating the association between response time and bystander CPR.

RESULTS

We included 1202 rural and 28,288 urban cardiac arrests. Comparing rural to urban OHCAs, rates of bystander CPR were significantly higher in rural communities (49.6% v 40.6%, aOR 1.3 95% CI 1.1-1.5). The median response time for rural (11.5 min) was longer than urban (7.3 min). The occurrence of an ambulance response time of <10 min was notably less common in rural communities when compared to urban areas (aOR 0.2, 95% CI 0.2-0.2). For post-arrest care the rates of percutaneous coronary intervention (PCI) were higher in rural than urban communities (aOR 1.7, 95% CI 1.01-2.8). The rates of AED and TTM were similar between urban and rural communities. Survival to hospital discharge was significantly lower in rural communities than urban communities (aOR 0.6, 95% CI 0.4-0.7). Although not significant, rural communities had lower rate of survival with a cognitive performance score (CPC) of 1 or 2 (aOR 0.7, 05% CI 0.6-1.003). We identified no association between response time and bystander CPR.

CONCLUSION

Patients in rural areas of Texas have lower survival after OHCA compared to patients in urban areas, despite having significantly greater rates of bystander CPR and PCI. We did not find a link between response time and bystander CPR rates.

Trends of Pulmonary Embolism-Related Sudden Cardiac Death in the United States, 1999-2019

OBJECTIVES

Up-to-date population-based data on pulmonary embolism (PE)-related sudden cardiac death (SCD) mortality trends in the United States (US) are scant. We assess the current trends in PE-related SCD mortality in US over the past two decades and determine differences by sex, race, ethnicity, age, and census region.

METHODS

We extracted PE-related SCD mortality rates from the Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research (CDC WONDER) database from 1999 to 2019, in patients aged ≥ 15 years old. Age-adjusted mortality rates (AAMRs) were assessed using the Joinpoint regression modeling and expressed as estimated average annual percentage change (AAPC) with relative 95% confidence intervals (CIs).

RESULTS

Between 1999 and 2019, the AAMR from acute PE-related SCD mortality in the US linearly increased [AAPC: +2.4% (95% CI: 2.2 to 2.6), p < 0.001)]. The AAMR increase was more pronounced in men [AAPC: +2.8% (95% CI: 2.6 to 2.9), p < 0.001], Whites [AAPC: +2.7% (95% CI: 2.3 to 3.1), p < 0.001], Latinx/Hispanic patients [AAPC:+2.0% (95% CI: 1.2 to 2.8), p < 0.001], subjects younger than 65 years [AAPC: +2.4% (95% CI: 2.1 to 2.6), p < 0.001] and in residents of rural areas [AAPC: +3.6% (95% CI: 3.3 to 3.9), p < 0.001]. Moreover, higher percentages of PE-related SCD and the relative absolute number of deaths were observed in the South compared with other geographical regions.

CONCLUSIONS

PE-related SCD mortality in the US has increased over the last two decades. Stratification by race, ethnicity, urbanization, and census region demonstrates ethnoracial and regional disparities that require further investigation and remedy.

Online platform for cardiopulmonary resuscitation and automated external defibrillator training in a rural area: a community clinical trial protocol

INTRODUCTION

Sudden death resulting from cardiorespiratory arrest carries a high mortality rate and frequently occurs out of hospital. Immediate initiation of cardiopulmonary resuscitation (CPR) by witnesses, combined with automated external defibrillator (AED) use, has proven to double survival rates. Recognising the challenges of timely emergency services in rural areas, the implementation of basic CPR training programmes can improve survival outcomes. This study aims to evaluate the effectiveness of online CPR-AED training among residents in a rural area of Tarragona, Spain.

METHODS

Quasi-experimental design, comprising two phases. Phase 1 involves assessing the effectiveness of online CPR-AED training in terms of knowledge acquisition. Phase 2 focuses on evaluating participant proficiency in CPR-AED simulation manoeuvres at 1 and 6 months post training. The main variables include the score difference between pre-training and post-training test (phase 1) and the outcomes of the simulated test (pass/fail; phase 2). Continuous variables will be compared using Student's t-test or Mann-Whitney U test, depending on normality. Pearson's χ2 test will be applied for categorical variables. A multivariate analysis will be conducted to identify independent factors influencing the main variable.

ETHICS AND DISSEMINATION

This study adheres to the tenets outlined in the Declaration of Helsinki and of Good Clinical Practice. It operated within the Smartwatch project, approved by the Clinical Research Ethics Committee of the Primary Care Research Institute IDIAP Jordi Gol i Gurina Foundation, code 23/081-P. Data confidentiality aligns with Spanish and European Commission laws for the protection of personal data. The study's findings will be published in peer-reviewed journals and presented at scientific meetings.

TRIAL REGISTRATION NUMBER

NCT05747495.

Does PM 2.5 and PM 10-associated heavy metals affect short-term and long-term survival after out-of-hospital cardiac arrest? Four-year study based on regional registry

BACKGROUND

This study aims to investigate the effect of arsenic (As), cadmium (Cd), nickel (Ni) and lead (Pb) suspended on particulate matters (PM) 2.5 and PM 10 taking into account clinical factors on 30-day and one-year survival after out-of-hospital cardiac arrest (OHCA).

METHODS

A retrospective 4-year study that involved patients hospitalized after OHCA. Patients' data were obtained from Emergency Medical Services dispatch cards and the National Health Fund. The concentration of air pollutants was measured by the Environmental Protection Inspectorate in Poland.

RESULTS

Among the 948 patients after OHCA, only 225 (23.7%) survived for 30 days, and 153 (16.1%) survived for 1 year. Survivors were more commonly affected by OHCA in urban areas (85 [55.6%] vs. 355 [44.7%]; P=0.013) and had slightly higher one-year mean concentration of As (0.78 vs. 0.77; P=0.01), Cd (0.34 vs. 0.34; P=0.012), and Pb (11.13 vs. 10.20; P=0.015) with no differences in daily mean concentration. Significant differences in mean concentrations of heavy metals and PM 2.5 and PM 10 were observed among different quarters. However, survival analysis revealed no differences in long-term survival between quarters. Heavy metals, PM 2.5, and PM 10 did not affect short-term and long-term survival in multivariable logistic regression.

CONCLUSIONS

The group of survivors showed slightly higher mean one-year concentrations of As, Cd and Pb, but they also experienced a higher incidence of OHCA in urban areas. There were no differences in long-term survival between patients who suffer OHCA in different quarters. Heavy metals did not independently affect survival.

Ambulance nurses' experiences as the sole caregiver with critical patients during long ambulance transports: an interview study

BACKGROUND

Working in rural areas involves tackling long distances and occasional lack of supportive resources. Ambulance nurses are faced with the responsibility of making immediate autonomous decisions and providing extended care to critically ill patients during prolonged ambulance transport to reach emergency medical facilities. This study aims to expose the experiences of ambulance nurses acting as primary caregivers for critically ill patients during lengthy ambulance transfers in rural regions.

METHOD

Fifteen nurses employed in an ambulance service within sparsely populated rural areas were subjected to semi-structured interviews. The collected data underwent qualitative content analysis.

RESULT

The analysis resulted in one overarching theme with two categories. The theme is 'Safety in the Professional Role,' and the two categories are 'Working in sparsely populated areas presents challenges' and 'Rare events: when routine cannot be established.' The findings suggest that working as an ambulance nurse in a rural setting poses various challenges that can be highly stressful. Delivering care to critically ill patients during extended ambulance transports requires the knowledge, experience, and careful planning of the healthcare provider in charge.

CONCLUSIONS

The findings underscore the necessity for thorough planning and adaptable thinking when attending to critically ill patients during extended transport scenarios. The absence of supporting resources can render the task demanding. Nevertheless, participants reported an inherent tranquility that aids them in maintaining focus amid their responsibilities.

Mortality trends, disparities, and social vulnerability in cardiac arrest mortality in the young: A cross-sectional analysis

BACKGROUND

Cardiac arrest (CA) is a leading cause of death in the United States (US). Social determinants of health may impact CA outcomes. We aimed to assess mortality trends, disparities, and the influence of the social vulnerability index (SVI) on CA outcomes in the young.

METHODS

We conducted a cross-sectional analysis of age-adjusted mortality rates (AAMRs) related to CA in the United States from the Years 1999 to 2020 in individuals aged 35 years and younger. Data were obtained from death certificates and analyzed using log-linear regression models. We examined disparities in mortality rates based on demographic variables. We also explored the impact of the SVI on CA mortality.

RESULTS

A total of 4792 CA deaths in the young were identified. Overall AAMR decreased from 0.20 in 1999 to 0.14 in 2020 with an average annual percentage change of -1.3% (p = .001). Black (AAMR: 0.30) and male populations (AAMR: 0.14) had higher AAMR compared with White (AAMR: 0.11) and female (AAMR: 0.11) populations, respectively. Nonmetropolitan (AAMR: 0.29) and Southern (AAMR: 0.26) regions were also impacted by higher AAMR compared with metropolitan (AAMR: 0.11) and other US census regions, respectively. A higher SVI was associated with greater mortality risks related to CA (risk ratio: 1.82 [95% CI, 1.77-1.87]).

CONCLUSIONS

Our analysis of CA in the young revealed disparities based on demographics, with a decline in AAMR from 1999 to 2020. There is a correlation between a higher SVI and increased CA mortality risk, highlighting the importance of targeted interventions to address these disparities effectively.

Rural versus urban out-of-hospital cardiac arrest response, treatment and outcomes in the North East of England from 2018 to 2019

Introduction

Out-of-hospital cardiac arrest (OHCA) is a time-sensitive medical emergency. There is international evidence to suggest that rural regions experience worse OHCA outcomes, such as reduced survival rates. The aim of this study was to quantitatively review and compare the OHCA response, treatment and pre-hospital outcomes in a single-centre ambulance service over a 1-year period in urban and rural areas.

Methods

This study used retrospective OHCA audit data from the North East Ambulance Service NHS Foundation Trust, from April 2018 to April 2019, comparing OHCA response, treatment and return of spontaneous circulation (ROSC) data in relation to urban or rural classification status, using the UK government urban-rural classification tool.

Results

A total of 1295 urban cases and 319 rural cases were compared. Bystander public-access defibrillator (PAD) use was higher in rural areas in comparison to urban areas (20/319 (6.3%) vs 47/1295 (3.6%); p = 0.03). The mean ambulance response time was slower in rural areas (10:43 minutes (n = 319) (SD ± 8.2) vs 07:35 minutes (n = 1295) (SD ± 7.1); p = < 0.01). Despite this, overall ROSC rates at hospital were similar between the groups, with no statistically significant difference (rural: 87/319 (27.3%) vs urban: 409/1295 (31.6%); p = 0.14).A further sub-group analysis of initially shockable OHCA cases showed slower ambulance response times in rural areas (10:45 minutes (n = 68) (SD ± 12.3) vs 07:55 minutes (n = 245) (SD ± 5.5); p = < 0.01) and that rural cases experienced lower ROSC at hospital rates (31/68 (45.6%) vs 151/245 (61.6%); p = 0.02).

Conclusion

This report showed differences in OHCA response and outcomes between rural and urban settings. In the shockable OHCA sub-group analysis, rural areas had slower ambulance response times and lower ROSC rates. The longer ambulance response times in the rural shockable OHCA group could be a factor in the reduced ROSC rates. Linking hospital survival data should be used in future research to explore this area further.

A Machine Learning Prediction Model for Non-cardiogenic Out-of-hospital Cardiac Arrest with Initial Non-shockable Rhythm

Objectives

The purpose of this study was to develop and validate a machine learning prediction model for the prognosis of non-cardiogenic out-of-hospital cardiac arrest (OHCA) with an initial non-shockable rhythm.

Design

Data were obtained from a nationwide OHCA registry in Japan. Overall, 222,056 patients with OHCA and an initial non-shockable rhythm were identified from the registry in 2016 and 2017. Patients aged <18 years and OHCA caused by cardiogenic origin, cancer, and external factors were excluded. Finally, 58,854 participants were included.

Methods

Patients were classified into the training dataset (n=29,304, data from 2016) and the test dataset (n=29,550, data from 2017). The training dataset was used to train and develop the machine learning model, and the test dataset was used for internal validation. We selected XGBoost as the machine learning classifier. The primary outcome was the poor prognosis defined as cerebral performance category of 3-5 at 1 month. Eleven prehospital variables were selected as outcome predictors.

Results

In validation, the machine learning model predicted the primary outcome with an accuracy of 90.8% [95% confidence interval (CI): 90.5-91.2], a sensitivity of 91.4% [CI: 90.7-91.4], a specificity of 74.1% [CI: 69.2-78.6], and an area under the receiver operating characteristic value of 0.89 [0.87-0.92]. The important features for model development were the prehospital return of spontaneous circulation, prehospital adrenaline administration, and initial electrical rhythm.

Conclusions

We developed a favorable machine learning model to predict the prognosis of non-cardiogenic OHCA with an initial non-shockable rhythm in the early stage of resuscitation.

Association of Degree of Urbanization and Survival in Out-of-Hospital Cardiac Arrest

Background Survival from out-of-hospital cardiac arrest (OHCA) varies across regions. The aim of this study was to evaluate the association between urbanization (rural, suburban, and urban areas), bystander interventions (cardiopulmonary resuscitation and defibrillation), and 30-day survival from OHCAs in Denmark. Methods and Results We included OHCAs not witnessed by ambulance staff in Denmark from January 1, 2016, to December 31, 2020. Patients were divided according to the Eurostat Degree of Urbanization Tool in rural, suburban, and urban areas based on the 98 Danish municipalities. Poisson regression was used to estimate incidence rate ratios. Logistic regression (adjusted for ambulance response time) tested differences between the groups with respect to bystander interventions and survival, according to degree of urbanization. A total of 21 385 OHCAs were included, of which 8496 (40%) occurred in rural areas, 7025 (33%) occurred in suburban areas, and 5864 (27%) occurred in urban areas. Baseline characteristics, as age, sex, location of OHCA, and comorbidities, were comparable between groups. The annual incidence rate ratio of OHCA was higher in rural areas (1.54 [95% CI, 1.48-1.58]) compared with urban areas. Odds for bystander cardiopulmonary resuscitation were lower in suburban (0.86 [95% CI, 0.82-0.96]) and urban areas (0.87 [95% CI, 0.80-0.95]) compared with rural areas, whereas bystander defibrillation was higher in urban areas compared with rural areas (1.15 [95% CI, 1.01-1.31]). Finally, 30-day survival was higher in suburban (1.13 [95% CI, 1.02-1.25]) and urban areas (1.17 [95% CI, 1.05-1.30]) compared with rural areas. Conclusions Degree of urbanization was associated with lower rates of bystander defibrillation and 30-day survival in rural areas compared with urban areas.

Treatment and outcome variation in out-of-hospital cardiac arrest among four urban hospitals in Detroit

AIMS

To determine whether out-of-hospital cardiac arrest (OHCA) post-resuscitation management and outcomes differ between four Detroit hospitals.

INTRODUCTION

Significant variation exists in treatment/outcomes from OHCA. Disparities between hospitals serving a similar population is not well known.

METHODS

Retrospective OHCA data was collected from the Detroit-Cardiac Arrest Registry (DCAR) between January 2014 to December 2019. Four hospitals were compared on two treatments (angiography, do not resuscitate (DNR)) and two outcomes (cerebral performance category (CPC) ≤ 2, in-hospital death). Models for death and CPC were tested with and without coronary angiography and DNR status.

RESULTS

999 patients at hospitals A - D differed (p < 0.05) before multivariable adjustment by age, race, witnessed arrest, dispatch-emergency department (ED) time, TTM, coronary angiography, DNR order, and in-hospital death. Rates of death and CPC ≤ 2 were worse in Hospital A (82.8%, 10%, respectively) compared to others (69.1%, 14.1%). After multivariable adjustment, Hospital A performed angiography less compared to B (OR = 0.17) and was more likely to initiate new DNR status than B (OR = 2.9), C (OR = 16.1), or D (OR = 3.6). CPC ≤ 2 were worse in Hospital A compared to B (OR = 0.27) and D (OR = 0.35). After sensitivity analysis, CPC ≤ 2 odds did not differ for A versus B (OR = 0.58, adjusted for angiography) or D (OR = 0.65, adjusted for DNR). Odds of death, despite angiography and DNR differences, were worse in Hospital A compared to B (OR = 1.87) and D (OR = 1.81).

CONCLUSION

Differing rates of DNR and coronary angiography was associated with observed disparities in favorable neurologic outcome, but not death, between four Detroit hospitals.

Differences in Out-of-Hospital Cardiac Arrest Management and Outcomes across Urban, Suburban, and Rural Settings

BACKGROUND

Rural prehospital care settings are underrepresented in the out-of-hospital cardiac arrest (OHCA) literature. This study aimed to describe treatment patterns and the odds of a favorable patient outcome (e.g., return of spontaneous circulation (ROSC) or being presumptively alive at the end of the incident) among rural OHCA patients in the U.S.

METHODS

Using the 2018 National Emergency Medical Services Informational System (NEMSIS) dataset, we analyzed OHCA incidents where an emergency medical services (EMS) unit provided cardiopulmonary resuscitation (CPR) and either terminated the resuscitation or completed transport. We excluded traumatic injuries, pediatric patients, and incidents with response time >60 minutes. The primary outcome was ROSC at any time during the EMS incident. The secondary outcome was a binary end-of-event indicator previously described for use in NEMSIS to estimate longer-term outcomes. Multivariable logistic regression was performed for each outcome measure comparing rural, suburban, and urban settings while controlling for key factors.

RESULTS

A total of 64,489 OHCA incidents were included, with 5,601 (8.9%) in rural settings. Among the full sample of OHCA incidents, ROSC was achieved in 20,578 (33.6%) cases, including 29.2% in rural settings and 34.1% in urban or suburban settings (p < 0.001). Advanced life support units responded to 95.3% of all calls, and a greater proportion of rural OHCA incidents were managed by basic life support units (7.4% vs. 4.2%, p < 0.001). Rural OHCA incidents had longer response times (7.5 vs. 5.9 minutes, p < 0.001), and rural patients were less likely to receive epinephrine (69.3% vs. 73.3%, p < 0.001). Further, EMS clinicians in rural areas were more likely to use mechanical CPR (29.5% vs. 27.6%, p < 0.01) and were less likely to perform advanced airway management (48.5% vs. 54.2%, p < 0.001). Rural patients had lower odds of achieving ROSC than urban patients after controlling for other factors (OR 0.81, 95% CI: 0.75-0.87). Rural patients also had lower odds of having a positive end-of-event outcome (i.e., presumptively alive) after controlling for other factors (OR 0.86, 95% CI: 0.79-0.93).

CONCLUSION

In this national sample of EMS-treated OHCAs, rural patients had lower odds of a favorable outcome (e.g., ROSC or presumptively alive) compared to those in urban settings.

Digital transition in rural emergency medicine: Impact of job satisfaction and workload on communication and technology acceptance

BACKGROUND

Tele-emergency physicians (TEPs) take an increasingly important role in the need-oriented provision of emergency patient care. To improve emergency medicine in rural areas, we set up the project 'Rural|Rescue', which uses TEPs to restructure professional rescue services using information and communication technologies (ICTs) in order to reduce the therapy-free interval. Successful implementation of ICTs relies on user acceptance and knowledge sharing behavior.

METHOD

We conducted a factorial design with active knowledge transfer and technology acceptance as a function of work satisfaction (high vs. low), workload (high vs. low) and point in time (prior to vs. after digitalization). Data were collected via machine readable questionnaires issued to 755 persons (411 pre, 344 post), of which 304 or 40.3% of these persons responded (194 pre, 115 post).

RESULTS

Technology acceptance was higher after the implementation of TEP for nurses but not for other professions, and it was higher when the workload was high. Regarding active communication and knowledge sharing, employees with low work satisfaction are more likely to share their digital knowledge as compared to employees with high work satisfaction. This is an effect of previous knowledge concerning digitalization: After implementing the new technology, work satisfaction increased for the more experienced employees, but not for the less experienced ones.

CONCLUSION

Our research illustrates that employees' workload has an impact on the intention of using digital applications. The higher the workload, the more people are willing to use TEPs. Regarding active knowledge sharing, we see that employees with low work satisfaction are more likely to share their digital knowledge compared to employees with high work satisfaction. This might be attributed to the Dunning-Kruger effect. Highly knowledgeable employees initially feel uncertain about the change, which translates into temporarily lower work satisfaction. They feel the urge to fill even small knowledge gaps, which in return leads to higher work satisfaction. Those responsible need to acknowledge that digital change affects their employees' workflow and work satisfaction. During such times, employees need time and support to gather information and knowledge in order to cope with digitally changed tasks.

The incidence and outcomes of out-of-hospital cardiac arrest in metropolitan versus rural locations: A systematic review and meta-analysis

BACKGROUND/AIMS

Rurality poses a unique challenge to the management of out-of-hospital cardiac arrest (OHCA) when compared to metropolitan (metro) locations. We conducted a systematic review of published literature to understand how OHCA incidence, management and survival outcomes vary between metro and rural areas.

METHODS

We included studies comparing the incidence or survival of ambulance attended OHCA in metropolitan and rural areas, from a search of five databases from inception until 9th March 2022. The primary outcomes of interest were cumulative incidence and survival (return of spontaneous circulation, survival to hospital discharge (or survival to 30 days)). Meta-analyses of OHCA survival were undertaken.

RESULTS

We identified 28 studies (30 papers- total of 823,253 patients) across 13 countries of origin. The definition of rurality varied markedly. There was no clear difference in OHCA incidence between metro and rural locations. Whilst there was considerable statistical heterogeneity between studies, the likelihood of return of spontaneous circulation on arrival at hospital was lower in rural than metro locations (OR = 0.53, 95% CI 0.40, 0.70; I² = 89%; 5 studies; 90,934 participants), as was survival to hospital discharge/survival to 30 days (OR = 0.52, 95% CI 0.38, 0.71; I² = 95%; 15 studies; 18,837 participants).

CONCLUSIONS

Overall, while incidence did not vary, the odds of OHCA survival to hospital discharge were approximately 50% lower in rural areas compared to metro areas. This suggests an opportunity for improvement in the prehospital management of OHCA within rural locations. This review also highlighted major challenges in standardising the definition of rurality in the context of cardiac arrest research.

Prehospital Time Interval for Urban and Rural Emergency Medical Services: A Systematic Literature Review

The aim of this study was to discuss the differences in pre-hospital time intervals between rural and urban communities regarding emergency medical services (EMS). A systematic search was conducted through various relevant databases, together with a manual search to find relevant articles that compared rural and urban communities in terms of response time, on-scene time, and transport time. A total of 37 articles were ultimately included in this review. The sample sizes of the included studies was also remarkably variable, ranging between 137 and 239,464,121. Twenty-nine (78.4%) reported a difference in response time between rural and urban areas. Among these studies, the reported response times for patients were remarkably variable. However, most of them (number (n) = 27, 93.1%) indicate that response times are significantly longer in rural areas than in urban areas. Regarding transport time, 14 studies (37.8%) compared this outcome between rural and urban populations. All of these studies indicate the superiority of EMS in urban over rural communities. In another context, 10 studies (27%) reported on-scene time. Most of these studies (n = 8, 80%) reported that the mean on-scene time for their populations is significantly longer in rural areas than in urban areas. On the other hand, two studies (5.4%) reported that on-scene time is similar in urban and rural communities. Finally, only eight studies (21.6%) reported pre-hospital times for rural and urban populations. All studies reported a significantly shorter pre-hospital time in urban communities compared to rural communities. Conclusions: Even with the recently added data, short pre-hospital time intervals are still superior in urban over rural communities.

Emergency medical services in rural and urban Saudi Arabia: A qualitative study of Red Crescent emergency personnel' perceptions of workforce and patient factors impacting effective delivery

Individuals who experience a traumatic injury or an acute illness are often reliant on initial healthcare assessment and support from a pre-hospital emergency medical service (EMS). These community-based support models perform a vital role in the provision of life-saving support, but research indicates that the availability, accessibility and resources of EMS are not equivalent in rural and urban areas, and there has been little recognition of the issues facing rural EMS provision outside of the USA, Europe and Australia. The purpose of the current study was to examine the lived experiences of Saudi Arabian EMS personnel, defined as emergency medical technicians, paramedics and local station managers. A semi-structured interview approach was used to collect data from 20 interviewees (10 each with rural and urban personnel) in the Riyadh region of the Kingdom of Saudi Arabia. This methodology was used to identify the key issues that these staff face in their day-to-day work practice and ascertain factors that may lead to service delivery issues in rural and urban areas. Data analyses identified three thematic categories impacting EMS delivery; two of these, Personnel Factors and Patient Factors, are the focus of this paper. The participants noted a number of key issues, including a lack of appropriate local training and limited resources in rural areas, as well as general areas of concern regarding the wider EMS staff demographic makeup and poor public awareness about the exact role of the EMS. Three key recommendations arising from this study include specialised training and ongoing accessible education for rural EMS staff to allow for better support for patients; consideration of supplementing the current EMS with additional external specialist staff; and the development and implementation of national public education programmes focusing on the role of the EMS within the community.

Rural-urban gradients and all-cause, cardiovascular and cancer mortality in Spain using individual data

•

The literature reporting on rural-urban health status disparities remains inconclusive.

•

We analyzed data from a longitudinal population-based study using individual observations.

•

Our results show that the risks of all-cause and cancer mortality are greater in large cities than in other municipalities, with no clear urban-rural gradient.

•

Not differences were found among territories in cardiovascular mortality.

Disparities in Survival Outcomes of Out-of-Hospital Cardiac Arrest Patients between Urban and Rural Areas and the Identification of Modifiable Factors in an Area of South Korea

This retrospective study aimed to compare the survival outcomes of adult out-of-hospital cardiac arrest (OHCA) patients between urban (Busan, Ulsan, Changwon) and rural (Gyeongnam) areas in South Korea and identify modifiable factors in the chain of survival. The primary and secondary outcomes were survival to discharge and modifiable factors in the chain of survival were identified using logistic regression analysis. In total, 1954 patients were analyzed. The survival to discharge rates in the whole region and in urban and rural areas were 6.9%, 8.7% (Busan 8.7%, Ulsan 10.3%, Changwon 7.2%), and 3.4%, respectively. In the urban group, modifiable factors associated with survival to discharge were no advanced airway management (adjusted odds ratio (aOR) 2.065, 95% confidence interval (CI): 1.138–3.747), no mechanical chest compression (aOR 3.932, 95% CI: 2.015–7.674), and an emergency medical service (EMS) transport time of more than 8 min (aOR 3.521, 95% CI: 2.075–5.975). In the rural group, modifiable factors included an EMS scene time of more than 15 min (aOR 0.076, 95% CI: 0.006–0.883) and an EMS transport time of more than 8 min (aOR 4.741, 95% CI: 1.035–21.706). To improve survival outcomes, dedicated resources and attention to EMS practices and transport time in urban areas and EMS scene and transport times in rural areas are needed.

Out-of-hospital cardiac arrest: Does rurality decrease chances of survival?

Background

Geographical setting is seldomly taken into account when investigating out-of-hospital cardiac arrest (OHCA). It is a common notion that living in rural areas means a lower chance of fast and effective helpwhen suffering a time-critical event. This retrospective cohort study investigates this hypothesis and compares across healthcare-divided administrative regions.

Methods

We included only witnessed OHCAs to minimize the risk that outcome was predetermined by time to caller arrival and/or recognition. Arrests were divided into public and residential. Residential arrests were categorized according to population density of the area in which they occurred. We investigated incidence, EMS response time and 30-day survival according to area type and subsidiarily by healthcare-divided administrative region.

Results

The majority (71%) of 8,579 OHCAs were residential, and 53.2% of all arrests occurred in the most densely populated cell group amongst residential arrests. This group had a median EMS response time of six minutes, whereas the most sparsely populated group had a median of 10 minutes. Public arrests also had a median response time of six minutes. 30-day survival was highest in public arrests (38.5%, [95% CI 36.9;40.1]), and varied only slightly with no statistical significance between OHCAs in densely and sparsely populated areas from 14.8% (95% CI 14.4;15.2) and 13.4% (95% CI 12.2;14.7).

Conclusion

Our study demonstrates that while EMS response times in Denmark are longer in the rural areas, there is no statistically significant decrease in survival compared to the most densely populated areas.

Effect of large-scale disasters on bystander-initiated cardiopulmonary resuscitation in family-witnessed, friend-witnessed and colleague-witnessed out-of-hospital cardiac arrest: a retrospective analysis of prospectively collected, nationwide, population-based data

IMPORTANCE

The effect of large-scale disasters on bystander cardiopulmonary resuscitation (BCPR) performance is unknown.

OBJECTIVE

To investigate whether and how large-scale earthquake and tsunami as well as subsequent nuclear pollution influenced BCPR performance for out-of-hospital cardiac arrest (OHCA) witnessed by family and friends/colleagues.

DESIGN AND SETTING

Retrospective analysis of prospectively collected, nationwide, population-based data for OHCA cases.

PARTICIPANTS

From the nationwide OHCA registry recorded between 11 March 2010 and 1 March 2013, we extracted 74 684 family-witnessed and friend/colleague-witnessed OHCA cases without prehospital physician involvement.

EXPOSURE

Earthquake and tsunamis that were followed by nuclear pollution and largely affected the social life of citizens for at least 24 weeks.

MAIN OUTCOME AND MEASURE

Neurologically favourable outcome after 1 month, 1-month survival and BCPR.

METHODS

We analysed the 4-week average trend of BCPR rates in the years affected and before and after the disaster. We used univariate and multivariate logistic regression analyses to investigate whether these disasters affected BCPR and OHCA results.

RESULTS

Multivariable logistic regression for tsunami-affected prefectures revealed that the BCPR rate during the impact phase in 2011 was significantly lower than that in 2010/2012 (42.5% vs 48.2%; adjusted OR; 95% CI 0.82; 0.68 to 0.99). A lower level of bystander compliance with dispatcher-assisted CPR instructions (62.1% vs 69.5%, 0.72; 95% CI 0.57 to 0.92) in the presence of a preserved level of voluntary BCPR performance (23.6% vs 23.8%) was also observed. Both 1-month survival and neurologically favourable outcome rates during the impact phase in 2011 were significantly poorer than those in 2010/2012 (8.5% vs 10.7%, 0.72; 95% CI 0.52 to 0.99, 4.0% vs 5.2%, 0.62; 95% CI 0.38 to 0.98, respectively).

CONCLUSION AND RELEVANCE

A large-scale disaster with nuclear pollution influences BCPR performance and clinical outcomes of OHCA witnessed by family and friends/colleagues. Basic life-support training leading to voluntary-initiated BCPR might serve as preparedness for disaster and major accidents.

The factor influencing the rate of ROSC for nontraumatic OHCA in New Taipei city

ABSTRACT

Return of spontaneous circulation (ROSC) from out-of-hospital cardiac arrest (OHCA) is critical for the Emergency Medical Services System. When compared to other developed countries, Taiwan has lower rate of ROSC in OHCA patients.We conducted a retrospective study of cardiac arrest using The Emergency Medical Service Dispatching Center in Northern Taiwan and The Prehospital Care System of New Taipei City Paramedic Service. Patients suffering from nontraumatic OHCA between August of 2019 to February of 2020 were included. We analyzed the cardiopulmonary resuscitation (CPR) quality parameters such as chest compression interruptions, bystander CPR, shockable rhythm, CPR interruption, chest compression fraction (CCF) average, patient transportation in buildings, and adrenaline injection during CPR. Multivariable logistic regression analysis was performed to assess the relationship between potential independent variables and ROSC.In our study, we involved 1265 subjects suffering from nontraumatic OHCA, among which 587 patients met inclusion criteria. We identified that CCF> 0.8, chest compression interruption greater than 3 times, and patient transportation in the building were the most critical factors influencing ROSC. However, patient transportation in a building was identified as a dependent predictor variable (P = .4752).We concluded that CCF > 0.8 and chest compression interruption greater than 3 times were essential factors affecting the CPR ROSC rate. The most significant reason for suboptimal CCF and CPR interruption is patient transportation in a building. Improving the latter point could facilitate high-quality CPR.

Long-term outcomes after out-of-hospital cardiac arrest: a systematic review and meta-analysis

AIMS

Long term outcomes after out-of-hospital cardiac arrest (OHCA) are not well understood. This study aimed to evaluate the long-term (1-year and beyond) survival outcomes, including overall survival and survival with favorable neurological status and the quality-of-life (QOL) outcomes, among patients who survived the initial OHCA event (30 days or till hospital discharge).

METHODS

Embase, Medline and PubMed were searched for primary studies (randomized controlled trials, cohort and cross-sectional studies) which reported the long-term survival outcomes of OHCA patients. Data abstraction and quality assessment was conducted, and survival at predetermined timepoints were assessed via single-arm meta-analyses of proportions, using generalized linear mixed models. Comparative meta-analyses were conducted using the Mantel-Haenszel Risk Ratio (RR) estimates, using the DerSimonian and Laird model.

RESULTS

67 studies were included, and among patients that survived to hospital discharge or 30-days, 77.3% (CI=71.2-82.4), 69.6% (CI=54.5-70.3), 62.7% (CI=54.5-70.3), 46.5% (CI=32.0-61.6), and 20.8% (CI=7.8-44.9) survived to 1-, 3-, 5-, 10- and 15-years respectively. Compared to Asia, the probability of 1-year survival was greater in Europe (RR=2.1, CI=1.8-2.3), North America (RR=2.0, CI=1.7-2.2) and Oceania (RR=1.9,CI=1.6-2.1). Males had a higher 1-year survival (RR:1.41, CI=1.25-1.59), and patients with initial shockable rhythm had improved 1-year (RR=3.07, CI=1.78-5.30) and 3-year survival (RR=1.45, CI=1.19-1.77). OHCA occurring in residential locations had worse 1-year survival (RR=0.42, CI=0.25-0.73).

CONCLUSION

Our study found that up to 20.8% of OHCA patients survived to 15-years, and survival was lower in Asia compared to the other regions. Further analysis on the differences in survival between the regions are needed to direct future long-term treatment of OHCA patients.

Positive association between ambulance double-crewing and OHCA outcomes: A New Zealand observational study

Background and objectives

New Zealand emergency medical service (EMS) crewing configurations generally place one (single) or two (double) crew on each responding ambulance unit. Recent studies demonstrated that double-crewing was associated with improved survival from out-of-hospital cardiac arrest (OHCA), therefore single-crewed ambulances have been phased out. We aimed to determine the association between this crewing policy change and OHCA outcomes in New Zealand.

Methods

This is a retrospective observational study using data from the St John OHCA Registry on patients treated during two different time periods: the Pre-Period (1 October 2013-30 June 2015), when single-crewed ambulances were in use by EMS, and the Post-Period (1 July 2016-30 June 2018) when single-crewed ambulances were being phased out. Geographic areas identified as having low levels of double crewing during the Pre-Period were selected for investigation. The outcome of survival to thirty-days post-OHCA was investigated using logistic regression analysis.

Results

The proportion of double-crewed ambulances arriving at OHCA events increased in the Post-Period (81.8%) compared to the Pre-Period (67.5%) (p ≤ 0.001). Response times decreased by two minutes (Pre-Period: median 8 min, IQR [6-11], Post-Period: median 6 min, IQR [4-9]; p ≤ 0.001). Thirty-day survival was significantly improved in the Post-Period (OR 1.63, 95%CI (1.04-2.55), p = 0.03).

Conclusions

An association between improved OHCA survival following increased responses by double-crewed ambulances was demonstrated. This study suggests that improvements in resourcing are associated with improved OHCA outcomes.

Longer retrieval distances to the automated external defibrillator reduces survival after out-of-hospital cardiac arrest

AIMS

To evaluate and compare survival after out-of-hospital (OHCA), where an automated external defibrillator (AED) was used, in densely, moderately and thinly populated areas. Also, to evaluate the association between AED retrieval distance and survival after OHCA.

METHODS

From 2014 to 2018, AEDs used during OHCA in the region of Southern Denmark were systematically collected. OHCAs were included if the OHCA address was known. OHCAs at nursing homes were excluded. To evaluate population density, a map with 1000 × 1000 meter grid cells was used with each cell color-graded according to the number of inhabitants. Densely, moderately and thinly populated areas were defined as ≥200 inhabitants, 20-199 inhabitants and 0-19 inhabitants per km², respectively. Primary outcome was 30-day survival.

RESULTS

A total of 423 cases of OHCA were included, of which 207 (49%) occurred in densely populated areas, while 78 (18%) and 138 (33%) occurred in moderately and thinly populated areas, respectively. AED retrieval distances were: densely populated 105 m (IQR 5-450), moderately populated 220 m (IQR 5-450) and thinly populated 350 m (IQR 5-1500) (P < 0.001). Thirty-day survival was 40%, 31% and 34%, respectively (P = 0.3). In a multivariable regression analysis, mortality increased with 10% per 100 m an AED was placed further away from the site of OHCA.

CONCLUSION

Survival after OHCA, where an AED was used, did not seem to differ in thinly, moderately and densely populated areas. The length of the AED retrieval distance, however, was correlated with reduced survival after adjusting for other potentially explanatory variables.

Machine Learning Models for Survival and Neurological Outcome Prediction of Out-of-Hospital Cardiac Arrest Patients

Background

Out-of-hospital cardiac arrest (OHCA) is a major health problem worldwide, and neurologic injury remains the leading cause of morbidity and mortality among survivors of OHCA. The purpose of this study was to investigate whether a machine learning algorithm could detect complex dependencies between clinical variables in emergency departments in OHCA survivors and perform reliable predictions of favorable neurologic outcomes.

Methods

This study included adults (≥18 years of age) with a sustained return of spontaneous circulation after successful resuscitation from OHCA between 1 January 2004 and 31 December 2014. We applied three machine learning algorithms, including logistic regression (LR), support vector machine (SVM), and extreme gradient boosting (XGB). The primary outcome was a favorable neurological outcome at hospital discharge, defined as a Glasgow-Pittsburgh cerebral performance category of 1 to 2. The secondary outcome was a 30-day survival rate and survival-to-discharge rate.

Results

The final analysis included 1071 participants from the study period. For neurologic outcome prediction, the area under the receiver operating curve (AUC) was 0.819, 0.771, and 0.956 in LR, SVM, and XGB, respectively. The sensitivity and specificity were 0.875 and 0.751 in LR, 0.687 and 0.793 in SVM, and 0.875 and 0.904 in XGB. The AUC was 0.766 and 0.732 in LR, 0.749 and 0.725 in SVM, and 0.866 and 0.831 in XGB, for survival-to-discharge and 30-day survival, respectively.

Conclusions

Prognostic models trained with ML technique showed appropriate calibration and high discrimination for survival and neurologic outcome of OHCA without using prehospital data, with XGB exhibiting the best performance.

Organisational factors affecting emergency medical services' performance in rural and urban areas of Saudi Arabia

Background

There is a disparity in outcomes between rural and urban emergency medical services (EMS) around the world. However, there is a scarcity of research that directly asks EMS staff in both rural and urban areas how service delivery could be improved. The aim of the present study is to gain insights from frontline workers regarding organisational factors that may underpin discrepancies between rural and urban EMS performance.

Subject and methods

The study was undertaken in the Riyadh region of Saudi Arabia. Potential participants were currently employed by Saudi Red Crescent EMS as either a technician, paramedic or an EMS station manager, and had a minimum of five years experience with the EMS. Semi-structured interviews were undertaken between October 2019 and July 2020 with first respondents to a call for participants, and continued until data saturation was reached. All interviews were conducted in Arabic and transcribed verbatim. The Arabic transcript was shared with each participant, and they were asked to confirm their agreement with the transcription. The transcribed interviews were then translated into English; the English versions were shared with bi-lingual participants for validation, while independent certification of the translations were performed for data from participants not fluent in English. A thematic analysis methodological approach was used to examine the data.

Results

The final sample involved 20 participants (10 rural, 10 urban) from Saudi Red Crescent EMS. Data analyses identified key organisational factors that resulted in barriers and impediments for EMS staff. Differences and similarities were observed between rural and urban respondents, with identified issues including response and transportation time, service coordination, reason for call-out, as well as human and physical resourcing.

Conclusion

The findings identified key issues impacting on EMS performance across both rural and urban areas. In order to address these problems, three changes are recommended. These recommendations include a comprehensive review of rural EMS vehicles, with a particular focus on the age; incentives to improve the numbers of paramedics in rural areas and more localised specialist training opportunities for rurally-based personnel; and the implementation of national public education program focusing on the role of the EMS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-021-06565-3.

Community Variations in Out-of-Hospital Cardiac Arrest Care and Outcomes in Texas

Background: Large and unacceptable variation exists in cardiac resuscitation care and outcomes across communities. Texas is the second most populous state in the US with wide variation in community and emergency response infrastructure. We utilized the Texas-CARES registry to perform the first Texas state analysis of out-of-hospital cardiac arrest (OHCA) in Texas, evaluating for variations in incidence, care, and outcomes.Methods: We analyzed the Texas-CARES registry, including all adult, non-traumatic OHCAs from 1/1/2014 through 12/31/2018. We analyzed the incidence and characteristics of OHCA care and outcome, overall and stratified by community. Utilizing mixed models accounting for clustering by community, we characterized variations in bystander CPR, bystander AED in public locations, and survival to hospital discharge across communities, adjusting for age, gender, race, location of arrest, and rate of witnessed arrest (bystander and 911 responder witnessed).Results: There were a total of 26,847 (5,369 per year) OHCAs from 13 communities; median 2,762 per community (IQR 444-2,767, min 136, max 9161). Texas care and outcome characteristics were: bystander CPR (43.3%), bystander AED use (9.1%), survival to discharge (9.1%), and survival with good neurological outcomes (4.0%). Bystander CPR rate ranged from 19.2% to 55.0%, and there were five communities above and five below the adjusted 95% confidence interval. Bystander AED use ranged from 0% to 19.5%, and there was one community below the adjusted 95% confidence interval. Survival to hospital discharge ranged from 6.7% to 14.0%, and there were three communities above and two below the adjusted 95% confidence interval.Conclusion: While overall OHCA care and outcomes were similar in Texas compared to national averages, bystander CPR, bystander AED use, and survival varied widely across communities in Texas. These variations signal opportunities to improve OHCA care and outcomes in Texas.

Response Time Threshold for Predicting Outcomes of Patients with Out-of-Hospital Cardiac Arrest

Ambulance response time is a prognostic factor for out-of-hospital cardiac arrest (OHCA), but the impact of ambulance response time under different situations remains unclear. We evaluated the threshold of ambulance response time for predicting survival to hospital discharge for patients with OHCA. A retrospective observational analysis was conducted using the emergency medical service (EMS) database (January 2015 to December 2019). Prehospital factors, underlying diseases, and OHCA outcomes were assessed. Receiver operating characteristic (ROC) curve analysis with Youden Index was performed to calculate optimal cut-off values for ambulance response time that predicted survival to hospital discharge. In all, 6742 cases of adult OHCA were analyzed. After adjustment for confounding factors, age (odds ratio [OR] = 0.983, 95% confidence interval [CI]: 0.975-0.992, p < 0.001), witness (OR = 3.022, 95% CI: 2.014-4.534, p < 0.001), public location (OR = 2.797, 95% CI: 2.062-3.793, p < 0.001), bystander cardiopulmonary resuscitation (CPR, OR = 1.363, 95% CI: 1.009-1.841, p=0.044), EMT-paramedic response (EMT-P, OR = 1.713, 95% CI: 1.282-2.290, p < 0.001), and prehospital defibrillation using an automated external defibrillator ([AED] OR = 3.984, 95% CI: 2.920-5.435, p < 0.001) were statistically and significantly associated with survival to hospital discharge. The cut-off value was 6.2 min. If the location of OHCA was a public place or bystander CPR was provided, the threshold was prolonged to 7.2 min and 6.3 min, respectively. In the absence of a witness, EMT-P, or AED, the threshold was reduced to 4.2, 5, and 5 min, respectively. The adjusted OR of EMS response time for survival to hospital discharge was 1.217 (per minute shorter, CI: 1.140-1299, p < 0.001) and 1.992 (<6.2 min, 95% CI: 1.496-2.653, p < 0.001). The optimal response time threshold for survival to hospital discharge was 6.2 min. In the case of OHCA in public areas or with bystander CPR, the threshold was prolonged, and without witness, the optimal response time threshold was shortened.

Development of unmanned aerial vehicle (UAV) networks delivering early defibrillation for out-of-hospital cardiac arrests (OHCA) in areas lacking timely access to emergency medical services (EMS) in Germany: a comparative economic study

OBJECTIVES

This study wants to assess the cost-effectiveness of unmanned aerial vehicles (UAV) equipped with automated external defibrillators (AED) in out-of-hospital cardiac arrests (OHCA). Especially in rural areas with longer response times of emergency medical services (EMS) early lay defibrillation could lead to a significant higher survival in OHCA.

PARTICIPANTS

3296 emergency medical stations in Germany.

SETTING

Rural areas in Germany.

PRIMARY AND SECONDARY OUTCOME MEASURES

Three UAV networks providing 80%, 90% or 100% coverage for rural areas lacking timely access to EMS (ie, time-to-defibrillation: >10 min) were developed using a location allocation analysis. For each UAV network, primary outcome was the cost-effectiveness using the incremental cost-effectiveness ratio (ICER) calculated by the ratio of financial costs to additional life years gained compared with current EMS.

RESULTS

Current EMS with 3926 emergency stations was able to gain 1224 life years on annual average in the study area. The UAV network providing 100% coverage consisted of 1933 UAV with average annual costs of €43.5 million and 1845 additional life years gained on annual average (ICER: €23 568). The UAV network providing 90% coverage consisted of 1074 UAV with average annual costs of €24.2 million and 1661 additional life years gained on annual average (ICER: €14 548). The UAV network providing 80% coverage consisted of 798 UAV with average annual costs of €18.0 million and 1477 additional life years gained on annual average (ICER: €12 158).

CONCLUSION

These results reveal the relevant life-saving potential of all modelled UAV networks. Furthermore, all analysed UAV networks could be deemed cost-effective. However, real-life applications are needed to validate the findings.

Association between prehospital prognostic factors on out-of-hospital cardiac arrest in different age groups

Background

The prognosis of out-of-hospital cardiac arrest (OHCA) is very poor. While several prehospital factors are known to be associated with improved survival, the impact of prehospital factors on different age groups is unclear. The objective of the study was to access the impact of prehospital factors and pre-existing comorbidities on OHCA outcomes in different age groups.

Methods

A retrospective observational analysis was conducted using the emergency medical service (EMS) database from January 2015 to December 2019. We collected information on prehospital factors, underlying diseases, and outcome of OHCAs in different age groups. Kaplan-Meier type survival curves and multivariable logistic regression were used to analyze the association between modifiable pre-hospital factors and outcomes.

Results

A total of 4188 witnessed adult OHCAs were analyzed. For the age group 1 (age ≦75 years old), after adjustment for confounding factors, EMS response time (odds ratio [OR] = 0.860, 95% confidence interval [CI]: 0.811–0.909, p < 0.001), public location (OR = 1.843, 95% CI: 1.179–1.761, p < 0.001), bystander CPR (OR = 1.329, 95% CI: 1.007–1.750, p = 0.045), attendance by an EMT-Paramedic (OR = 1.666, 95% CI: 1.277–2.168, p < 0.001), and prehospital defibrillation by automated external defibrillator (AED)(OR = 1.666, 95% CI: 1.277–2.168, p < 0.001) were prognostic factors for survival to hospital discharge in OHCA patients. For the age group 2 (age > 75 years old), age (OR = 0.924, CI:0.880–0.966, p = 0.001), EMS response time (OR = 0.833, 95% CI: 0.742–0.928, p = 0.001), public location (OR = 4.290, 95% CI: 2.450–7.343, p < 0.001), and attendance by an EMT-Paramedic (OR = 2.702, 95% CI: 1.704–4.279, p < 0.001) were independent prognostic factors for survival to hospital discharge in OHCA patients.

Conclusions

There were variations between younger and older OHCA patients. We found that bystander CPR and prehospital defibrillation by AED were independent prognostic factors for younger OHCA patients but not for the older group.

Pre-hospital Prognostic Factors of Out-of-Hospital Cardiac Arrest: The Difference Between Pediatric and Adult

The prognosis of out-of-hospital cardiac arrest (OHCA) is very poor. Although several pre-hospital factors are associated with survival, the different association of pre-hospital factors with OHCA outcomes in pediatric and adult groups remain unclear. To assess the association of pre-hospital factors with OHCA outcomes among pediatric and adult groups, a retrospective observational study was conducted using the emergency medical service (EMS) database in Kaohsiung from January 2015 to December 2019. Pre-hospital factors, underlying diseases, and OHCA outcomes were collected for the pediatric (Age ≤ 20) and adult groups. Kaplan-Meier type plots and multivariable logistic regression were used to analyze the association between pre-hospital factors and outcomes. In total, 7,461 OHCAs were analyzed. After adjusting for EMS response time, bystander CPR, attended by EMT-P, witness, and pre-hospital defibrillation, we found that age [odds ratio (OR) = 0.877, 95% confidence interval (CI): 0.764-0.990, p = 0.033], public location (OR = 7.681, 95% CI: 1.975-33.428, p = 0.003), and advanced airway management (AAM) (OR = 8.952; 95% CI, 1.414-66.081; p = 0.02) were significantly associated with survival till hospital discharge in pediatric OHCAs. The results of Kaplan-Meier type plots with log-rank test showed a significant difference between the pediatric and adult groups in survival for 2 h (p < 0.001), 24 h (p < 0.001), hospital discharge (p < 0.001), and favorable neurologic outcome (p < 0.001). AAM was associated with improved survival for 2 h (p = 0.015), 24 h (p = 0.023), and neurologic outcome (p = 0.018) only in the pediatric group. There were variations in prognostic factors between pediatric and adult patients with OHCA. The prognosis of the pediatric group was better than that of the adult group. Furthermore, AAM was independently associated with outcomes in pediatric patients, but not in adult patients. Age and public location of OHCA were independently associated with survival till hospital discharge in both pediatric and adult patients.

Association between prehospital prognostic factors and out-of-hospital cardiac arrest: Effect of rural-urban disparities

BACKGROUND

Out-of-hospital cardiac arrest (OHCA) is associated with a poor prognosis and a highly variable survival rate. Few studies have focused on outcomes in rural and urban groups while also evaluating underlying diseases and prehospital factors for OHCAs.

OBJECTIVE

To investigate the relationship between the patient's underlying disease and outcomes of OHCAs in urban areas versus those in rural areas.

METHODS

We reviewed the emergency medical service (EMS) database for information on OHCA patients treated between January 2015 and December 2019, and collected data on pre-hospital factors, underlying diseases, and outcomes of OHCAs. Univariate and multivariate logistic regression analyses were used to evaluate the prognostic factors for OHCA.

RESULTS

Data from 4225 OHCAs were analysed. EMS response time was shorter and the rate of attendance by EMS paramedics was higher in urban areas (p < 0.001 for both). Urban area was a prognostic factor for >24-h survival (odds ratio [OR] = 1.437, 95% confidence interval [CI]: 1.179-1.761). Age (OR = 0.986, 95% CI: 0.979-0.993). EMS response time (OR = 0.854, 95% CI: 0.811-0.898), cardiac arrest location (OR = 2.187, 95% CI: 1.707-2.795), attendance by paramedics (OR = 1.867, 95% CI: 1.483-2.347), and prehospital defibrillation (OR = 2.771, 95% CI: 2.154-3.556) were independent risk factors for survival to hospital discharge, although the influence of an urban area was not significant (OR = 1.211, 95% CI: 0.918-1.584).

CONCLUSIONS

Compared with rural areas, OHCA in urban areas are associated with a higher 24-h survival rate. Shorter EMS response time and a higher probability of being attended by paramedics were noted in urban areas. Although shorter EMS response time, younger age, public location, defibrillation by an automated external defibrillator, and attendance by Emergency Medical Technician-paramedics were associated with a higher rate of survival to hospital discharge, urban area was not an independent prognostic factor for survival to hospital discharge in OHCA patients.

Improving Access to Automated External Defibrillators in Rural and Remote Settings: A Drone Delivery Feasibility Study

Background Time to treatment is critical for survival from sudden cardiac arrest. Every minute delay in defibrillation results in a 7% to 10% reduction in survival. This is particularly problematic in rural and remote regions, where emergency medical service response is prolonged and automated external defibrillators (AEDs) are often not available. Our primary objective was to examine the feasibility of a novel AED drone delivery method for rural and remote sudden cardiac arrest. A secondary objective was to compare response times between AED drone delivery and ambulance to mock sudden cardiac arrest resuscitations. Methods and Results We conducted 6 simulations in 2 rural communities in southern Ontario, Canada. In the first 2 simulations, the drone and ambulance were dispatched from the same paramedic base. In simulations 3 and 4, the drone and ambulance were dispatched from separate paramedic bases; and in simulations 5 and 6, the drone was dispatched from an optimized location. During each simulation, a "mock" call was placed to 911 and a single AED drone and an ambulance were simultaneously dispatched to a predetermined destination. On scene, trained first responders retrieved the AED from the drone and initiated resuscitative efforts on a mannequin until paramedics arrived. No difficulties were encountered during drone activation by dispatch, ascent, landing, or bystander retrieval of the AED from the drone. During simulations 1 and 2, the distance to the scene was 6.6 km. For simulations 3 and 4, the ambulance response distance increased to 8.8 km while drone remained at 6.6 km; and in simulations 5 and 6, the ambulance response distance was 20 km compared with 9 km for the drone. During each flight, the AED drone arrived on scene before the ambulance, between 1.8 and 8.0 minutes faster. Conclusions This study suggests AED drone delivery is feasible, with the potential for improvements in response time during simulated sudden cardiac arrest scenarios. Further research is required to determine the appropriate system configuration for AED drone delivery in an integrated emergency medical service system as well as optimal strategies to simplify bystander application of a drone-delivered AED.

Association between ambient air pollution and out-of-hospital cardiac arrest: are there potentially susceptible groups?

This study aimed to examine the association between air pollution and out-of-hospital cardiac arrest (OHCA), and the effects of underlying diseases. Between January 2015 and December 2016, data on particulate matter (PM)_2.5 and other air pollutants in Kaohsiung City were collected, and an emergency medical service database was used for information on patients who experienced OHCA. Overall, 3566 patients were analyzed and subgroup analyses by sex, age, and preexisting morbidities were performed. Interquartile increments in PM_2.5, PM₁₀, and O₃ levels on lag 1 and NO₂ level on lag 3 were associated with increments of 10.8%, 11.3%, 6.2%, and 1.7% in OHCA incidence, respectively. Subgroup analyses showed that patients with diabetes (1.363; interaction p = 0.009), heart disease (1.612; interaction p = 0.001), and advanced age (≥70 years, 1.297; interaction p = 0.003) were more susceptible to NO₂ on lag 3. Moreover, patients were more susceptible to O₃ during the cold season (1.194; interaction p = 0.001). We found that PM_2.5, PM₁₀, NO₂, and O₃ may play an important role in OHCA events, and the effects vary by underlying condition, age and season.

Barriers to bystander CPR in deprived communities: Findings from a qualitative study

STUDY AIM

Rates of out of hospital cardiac arrest are higher in deprived communities. Bystander Cardiopulmonary Resuscitation (BCPR) can double the chance of survival but occurs less often in these communities in comparison to more affluent communities. People living in deprived communities are, therefore, doubly disadvantaged and there is limited evidence to explain why BCPR rates are lower. The aim of this paper is to examine the barriers to administering BCPR in deprived communities.

METHOD

Mixed method qualitative study with ten single sex focus groups (n = 61) conducted in deprived communities across central Scotland and 18 semi-structured interviews with stakeholders from the UK, Europe and the USA.

RESULTS

Two key themes related to confidence and environmental factors were identified to summarise the perceived barriers to administering BCPR in deprived communities. Barriers related to confidence included: self-efficacy; knowledge and awareness of how, and when, to administer CPR; accessing CPR training; having previous experience of administering BCPR; who required CPR; and whether the bystander was physically fit to give CPR. Environmental barriers focused on the safety of the physical environment in which people lived, and fear of reprisal from gangs or the police.

CONCLUSIONS

Barriers to administering BCPR identified in the general population are relevant to people living in deprived communities but are exacerbated by a range of contextual, individual and environmental factors. A one-size-fits-all approach is not sufficient to promote 'CPR readiness' in deprived communities. Future approaches to working with disadvantaged communities should be tailored to the local community.

Out-of-hospital cardiac arrests in the young population; a 6-year review of the Irish out-of-hospital cardiac arrest register

STUDY PURPOSE

Out-of-hospital cardiac arrests (OHCA) in the young population have only been examined in a limited number of regional studies. Hence, we sought to describe OHCA characteristics and predictors of survival to hospital discharge for the young Irish population.

STUDY DESIGN

An observational analysis of the national Irish OHCA register for all OHCAs aged ≤35 years between January 2012 and December 2017 was performed. The young population was categorised into three age groups: ≤1 year, 1-15 years and 16-35 years. Multivariable logistic regression was used to determine the independent predictors of survival to hospital discharge.

RESULTS

A total of 1295 OHCAs aged ≤35 years (26.9% female, median age 25 (IQR 17-31)) had resuscitation attempted. OHCAs in those aged ≥16 years (n=1005) were more likely to happen outside the home (38.5% vs 22.8%, p<0.001) and be of non-medical aetiology (59% vs 27.6%, p<0.001) compared with those aged <16 years (n=290). Asphyxiation, trauma and drug overdoses accounted for over 90% of the non-medical OHCAs for those 16-35 years. Overall survival to hospital discharge for the cohort was 5.1%; survival was non-significantly higher for those aged 16-35 years compared with those aged 1-15 years (6.0%, vs 2.8% p=0.93). Independent predictors of survival to hospital discharge included bystander witnessed OHCA, a shockable initial rhythm and a bystander defibrillation attempt.

CONCLUSIONS

The high prevalence of non-medical OHCAs and the OHCA location need to be considered when developing OHCA care pathways and preventative strategies to reduce the burden of OHCAs in the young population.

Evaluation of a Rural Emergency Medical Service Project in Germany: Protocol for a Multimethod and Multiperspective Longitudinal Analysis

BACKGROUND

German emergency medical services are a 2-tiered system with paramedic-staffed ambulances as the primary response, supported by prehospital emergency doctors for life-threatening conditions. As in all European health care systems, German medical practitioners are in short supply, whereas the demand for timely emergency medical care is constantly growing. In rural areas, this has led to critical delays in the provision of emergency medical care. In particular, in cases of cardiac arrest, time is of the essence because, with each passing minute, the chance of survival with good neurological outcome decreases.

OBJECTIVE

The project has 4 main objectives: (1) reduce the therapy-free interval through widespread reinforcement of resuscitation skills and motivating the public to provide help (ie, bystander cardiopulmonary resuscitation), (2) provide faster professional first aid in addition to rescue services through alerting trained first aiders by mobile phone, (3) make more emergency physicians available more quickly through introducing the tele-emergency physician system, and (4) enhance emergency care through improving the cooperation between statutory health insurance on-call medical services (German: Kassenärztlicher Bereitschaftsdienst) and emergency medical services.

METHODS

We will evaluate project implementation in a tripartite prospective and intervention study. First, in medical evaluation, we will assess the influences of various project measures on quality of care using multiple methods. Second, the economic evaluation will mainly focus on the valuation of inputs and outcomes of the different measures while considering various relevant indicators. Third, as part of the work and organizational analysis, we will assess important work- and occupational-related parameters, as well as network and regional indexes.

RESULTS

We started the project in 2017 and will complete enrollment in 2020. We finished the preanalysis phase in September 2018.

CONCLUSIONS

Overall, implementation of the project will entail realigning emergency medicine in rural areas and enhancing the quality of medical emergency care in the long term. We expect the project to lead to a measurable increase in medical laypersons' individual motivation to provide resuscitation, to strengthen resuscitation skills, and to result in medical laypersons providing first aid much more frequently. Furthermore, we intend the project to decrease the therapy-free interval in cases of cardiac arrest by dispatching first aiders via mobile phones. Previous projects in urban regions have shown that the tele-emergency physician system can provide a higher availability and quality of emergency call-outs in regular health care. We expect a closer interrelation of emergency practices of statutory health insurance physicians with the rescue service to lead to better coordination of rescue and on-call services.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/14358.

Postresuscitation Care after Out-of-hospital Cardiac Arrest: Clinical Update and Focus on Targeted Temperature Management

Out-of-hospital cardiac arrest is a major cause of mortality and morbidity worldwide. With the introduction of targeted temperature management more than a decade ago, postresuscitation care has attracted increased attention. In the present review, we discuss best practice hospital management of unconscious out-of-hospital cardiac arrest patients with a special focus on targeted temperature management. What is termed post-cardiac arrest syndrome strikes all organs and mandates access to specialized intensive care. All patients need a secured airway, and most patients need hemodynamic support with fluids and/or vasopressors. Furthermore, immediate coronary angiography and percutaneous coronary intervention, when indicated, has become an essential part of the postresuscitation treatment. Targeted temperature management with controlled sedation and mechanical ventilation is the most important neuroprotective strategy to take. Targeted temperature management should be initiated as quickly as possible, and according to international guidelines, it should be maintained at 32° to 36°C for at least 24 h, whereas rewarming should not increase more than 0.5°C per hour. However, uncertainty remains regarding targeted temperature management components, warranting further research into the optimal cooling rate, target temperature, duration of cooling, and the rewarming rate. Moreover, targeted temperature management is linked to some adverse effects. The risk of infection and bleeding is moderately increased, as is the risk of hypokalemia and magnesemia. Circulation needs to be monitored invasively and any deviances corrected in a timely fashion. Outcome prediction in the individual patient is challenging, and a self-fulfilling prophecy poses a real threat to early prognostication based on clinical assessment alone. Therefore, delayed and multimodal prognostication is now considered a key element of postresuscitation care. Finally, modern postresuscitation care can produce good outcomes in the majority of patients but requires major diagnostic and therapeutic resources and specific training. Hence, recent international guidelines strongly recommend the implementation of regional prehospital resuscitation systems with integrated and specialized cardiac arrest centers.

Systematic review of the relationship between comorbidity and out-of-hospital cardiac arrest outcomes

OBJECTIVES

To assess the current evidence on the effect pre-arrest comorbidity has on survival and neurological outcomes following out-of-hospital cardiac arrest (OHCA).

DESIGN

Systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

DATA SOURCES

MEDLINE, Ovid Embase, Scopus, CINAHL, Cochrane Library and MedNar were searched from inception to 31 December 2018.

ELIGIBILITY CRITERIA

Studies included if they examined the association between prearrest comorbidity and OHCA survival and neurological outcomes in adult or paediatric populations.

DATA EXTRACTION AND SYNTHESIS

Data were extracted from individual studies but not pooled due to heterogeneity. Quality of included studies was assessed using the Newcastle-Ottawa Quality Assessment Scale.

RESULTS

This review included 29 observational studies. There were high levels of clinical heterogeneity between studies with regards to patient recruitment, inclusion criteria, outcome measures and statistical methods used which ultimately resulted in a high risk of bias. Comorbidities reported across the studies were diverse, with some studies reporting individual comorbidities while others reported comorbidity burden using tools like the Charlson Comorbidity Index. Generally, prearrest comorbidity was associated with both reduced survival and poorer neurological outcomes following OHCA with 79% (74/94) of all reported adjusted results across 23 studies showing effect estimates suggesting lower survival with 42% (40/94) of these being statistically significant. OHCA survival was particularly reduced in patients with a prior history of diabetes (four out of six studies). However, a prearrest history of myocardial infarction appeared to be associated with increased survival in one of four studies.

CONCLUSIONS

Prearrest comorbidity is generally associated with unfavourable OHCA outcomes, however differences between individual studies makes comparisons difficult. Due to the clinical and statistical heterogeneity across the studies, no meta-analysis was conducted. Future studies should follow a more standardised approach to investigating the impact of comorbidity on OHCA outcomes.

PROSPERO REGISTRATION NUMBER

CRD42018087578.