The significance of pre-arrest factors in out-of-hospital cardiac arrests witnessed by emergency medical services: a report from the Victorian Ambulance Cardiac Arrest Registry

Prodromal complaints and 30-day survival after emergency medical services-witnessed out-of-hospital cardiac arrest

BACKGROUND

Out-of-hospital cardiac arrest (OHCA) is a frequent and lethal condition with a yearly incidence of approximately 5000 in Denmark. Thirty-day survival is associated with the patient's prodromal complaints prior to cardiac arrest. This paper examines the odds of 30-day survival dependent on the reported prodromal complaints among OHCAs witnessed by the emergency medical services (EMS).

METHODS

EMS-witnessed OHCAs in the Capital Region of Denmark from 2016-2018 were included. Calls to the emergency number 1-1-2 and the medical helpline for out-of-hours were analyzed according to the Danish Index; data regarding the OHCA was collected from the Danish Cardiac Arrest Registry. We performed multiple logistic regression to calculate the odds ratio (OR) of 30-day survival with adjustment for sex and age.

RESULTS

We identified 311 eligible OHCAs of which 79 (25.4%) survived. The most commonly reported complaints were dyspnea (n = 209, OR 0.79 [95% CI 0.46: 1.36]) and 'feeling generally unwell' (n = 185, OR 1.07 [95% CI 0.63: 1.81]). Chest pain (OR 9.16 [95% CI 5.09:16.9]) and heart palpitations (OR 3.15 [95% CI 1.07:9.46]) had the highest ORs, indicating favorable odds for 30-day survival, while unresponsiveness (OR 0.22 [95% CI 0.11:0.43]) and blue skin or lips (OR 0.30, 95% CI 0.09, 0.81) had the lowest, indicating lesser odds of 30-day survival.

CONCLUSION

Experiencing chest pain or heart palpitations prior to EMS-witnessed OHCA was associated with higher 30-day survival. Conversely, complaints of unresponsiveness or having blue skin or lips implied reduced odds of 30-day survival.

Artificial Intelligence Model Predicts Sudden Cardiac Arrest Manifesting With Pulseless Electric Activity Versus Ventricular Fibrillation

BACKGROUND

There is no specific treatment for sudden cardiac arrest (SCA) manifesting as pulseless electric activity (PEA) and survival rates are low; unlike ventricular fibrillation (VF), which is treatable by defibrillation. Development of novel treatments requires fundamental clinical studies, but access to the true initial rhythm has been a limiting factor.

METHODS

Using demographics and detailed clinical variables, we trained and tested an AI model (extreme gradient boosting) to differentiate PEA-SCA versus VF-SCA in a novel setting that provided the true initial rhythm. A subgroup of SCAs are witnessed by emergency medical services personnel, and because the response time is zero, the true SCA initial rhythm is recorded. The internal cohort consisted of 421 emergency medical services-witnessed out-of-hospital SCAs with PEA or VF as the initial rhythm in the Portland, Oregon metropolitan area. External validation was performed in 220 emergency medical services-witnessed SCAs from Ventura, CA.

RESULTS

In the internal cohort, the artificial intelligence model achieved an area under the receiver operating characteristic curve of 0.68 (95% CI, 0.61-0.76). Model performance was similar in the external cohort, achieving an area under the receiver operating characteristic curve of 0.72 (95% CI, 0.59-0.84). Anemia, older age, increased weight, and dyspnea as a warning symptom were the most important features of PEA-SCA; younger age, chest pain as a warning symptom and established coronary artery disease were important features associated with VF.

CONCLUSIONS

The artificial intelligence model identified novel features of PEA-SCA, differentiated from VF-SCA and was successfully replicated in an external cohort. These findings enhance the mechanistic understanding of PEA-SCA with potential implications for developing novel management strategies.

Effect of a national awareness campaign on ambulance attendances for chest pain and out-of-hospital cardiac arrest

AIM

Awareness of heart attack symptoms may enhance health-seeking behaviour and prevent premature deaths from out-of-hospital cardiac arrest (OHCA). We sought to investigate the impact of a national awareness campaign on emergency medical service (EMS) attendances for chest pain and OHCA.

METHODS

Between January 2005 and December 2017, we included registry data for 97,860 EMS-attended OHCA cases from 3 Australian regions and dispatch data for 1,631,217 EMS attendances for chest pain across 5 Australian regions. Regions were exposed to between 11 and 28 months of television, radio, and print media activity. Multivariable negative binomial models were used to explore the effect of campaign activity on the monthly incidence of EMS attendances for chest pain and OHCA.

RESULTS

Months with campaign activity were associated with an 8.8% (IRR 1.09, 95% CI: 1.07, 1.11) increase in the incidence of EMS attendances for chest pain and a 5.6% (IRR 0.94, 95% CI: 0.92, 0.97) reduction in OHCA attendances. Larger intervention effects were associated with increasing months of campaign activity, increasing monthly media spending and media exposure in 2013. In stratified analyses of OHCA cases, the largest reduction in incidence during campaign months was observed for unwitnessed arrests (IRR 0.93, 95% CI: 0.90, 0.96), initial non-shockable arrests (IRR 0.93, 95% CI: 0.90, 0.97) and arrests occurring in private residences (IRR 0.95, 95% CI: 0.91, 0.98).

CONCLUSION

A national awareness campaign targeting knowledge of heart attack symptoms was associated with an increase in EMS use for chest pain and a reduction in OHCA incidence and may serve as an effective primary prevention strategy for OHCA.

Prognostic predictors in patients with cardiopulmonary arrest: A novel equation for evaluating the 30-day mortality

BACKGROUND

Early prediction of outcomes after cardiopulmonary arrest (CPA) is important for considering the best support. Our purpose was to evaluate predictors of the 30-day mortality in patients with CPA after return of spontaneous circulation (ROSC) and to assess an equation for calculating the 30-day mortality using clinical parameters.

METHODS

We retrospectively analyzed the data of 194 consecutive patients with CPA and ROSC in a derivation study (2015-2022). We compared clinical parameters between the survived (n = 78) and dead (n = 116) patients. We derived an equation for estimated probability of death based on clinical parameters, using multivariate logistic regression analysis. The reliability of the equation was validated in 80 additional patients with CPA.

RESULTS

The 30-day mortality was associated with sex, witnessed cardiac arrest, bystander cardiopulmonary resuscitation (CPR), CPA due to acute myocardial infarction, pupil diameter, Glasgow Coma Scale score (GCS), presence of light reflex, arterial or venous pH, lactate levels, initial ventricular fibrillation (VF), CPA time, and age. The derived logistic regression equation was as follows: Estimated probability of death = 1 / (1 + e-x), x = (0.25 × bystander CPR) + (0.44 × pupil diameter) - (0.14 × GCS) + (0.09 × lactate) - (1.87 × initial VF) + (0.07 × CPA time) + (0.05 × age) - 7.03. The cut-off value for estimated probability of death calculated by this equation was 54.5 %, yielding a sensitivity, specificity, and accuracy of 86.2 %, 80.8 %, and 84.5 %, respectively. In the validation model, these values were 81.8 %, 85.7 %, and 82.5 %, respectively.

CONCLUSIONS

The 30-day mortality may be calculated after ROSC in patients with CPA using simple clinical parameters. This equation may facilitate further best support for patients with CPA.

The development of a risk-adjustment strategy to benchmark emergency medical service (EMS) performance in relation to out-of-hospital cardiac arrest in Australia and New Zealand

INTRODUCTION

The aim of this study was to develop a risk adjustment strategy, including effect modifiers, for benchmarking emergency medical service (EMS) performance for out-of-hospital cardiac arrest (OHCA) in Australia and New Zealand.

METHOD

Using 2017-2019 data from the Australasian Resuscitation Outcomes Consortium (Aus-ROC) OHCA Epistry, we included adults who received an EMS attempted resuscitation for a presumed medical OHCA. Logistic regression was applied to develop risk adjustment models for event survival (return of spontaneous circulation at hospital handover) and survival to hospital discharge/30 days. We examined potential effect modifiers, and assessed model discrimination and validity.

RESULTS

Both OHCA survival outcome models included EMS agency and the Utstein variables (age, sex, location of arrest, witnessed arrest, initial rhythm, bystander cardiopulmonary resuscitation, defibrillation prior to EMS arrival, and EMS response time). The model for event survival had good discrimination according to the concordance statistic (0.77) and explained 28% of the variation in survival. The corresponding figures for survival to hospital discharge/30 days were 0.87 and 49%. The addition of effect modifiers did little to improve the performance of either model.

CONCLUSION

The development of risk adjustment models with good discrimination is an important step in benchmarking EMS performance for OHCA. The Utstein variables are important in risk-adjustment, but only explain a small proportion of the variation in survival. Further research is required to understand what factors contribute to the variation in survival between EMS.

The effect of the COVID-19 pandemic on the incidence and survival outcomes of EMS-witnessed out-of-hospital cardiac arrest

AIM

We sought to examine the impact of the COVID-19 pandemic on the incidence and survival outcomes of emergency medical service (EMS)-witnessed out-of-hospital cardiac arrest (OHCA) in Victoria, Australia.

METHODS

We performed an interrupted time-series analysis of adult EMS-witnessed OHCA patients of medical aetiology. Patients treated during the COVID-19 period (1st March 2020 to 31st December 2021) were compared to a historical comparator period (1st January 2012 and 28th February 2020). Multivariable poisson and logistic regression models were used to examine changes in incidence and survival outcomes during the COVID-19 pandemic, respectively.

RESULTS

We included 5,034 patients, 3,976 (79.0%) in the comparator period and 1,058 (21.0%) in the COVID-19 period. Patients in the COVID-19 period had longer EMS response times, fewer public location arrests and were significantly more likely to receive mechanical CPR and laryngeal mask airways compared to the historical period (all p < 0.05). There were no significant differences in the incidence of EMS-witnessed OHCA between the comparator and COVID-19 periods (incidence rate ratio 1.06, 95% CI: 0.97-1.17, p = 0.19). Also, there was no difference in the risk-adjusted odds of survival to hospital discharge for EMS-witnessed OHCA occurring during COVID-19 period compared to the comparator period (adjusted odd ratio 1.02, 95% CI: 0.74-1.42; p = 0.90).

CONCLUSION

Unlike the reported findings in non-EMS-witnessed OHCA populations, changes during the COVID-19 pandemic did not influence incidence or survival outcomes in EMS-witnessed OHCA. This may suggest that changes in clinical practice that sought to limit the use of aerosol generating procedures did not influence outcomes in these patients.

Symptoms reported in calls to emergency medical services within 24 hours prior to out-of-hospital cardiac arrest

AIM

There is limited evidence regarding prodromal symptoms of out-of-hospital cardiac arrest (OHCA). We aimed to describe patient characteristics, prodromal symptoms, and prognosis of patients contacting emergency medical services (EMS) within 24 hours before OHCA.

METHODS

We identified all OHCA treated by Copenhagen EMS from 2016 through 2018 using the Danish Cardiac Arrest Registry and linked them to emergency calls. We included all pre-arrest calls by patients or bystanders if they were performed 1) within 24 hours before the OHCA call or 2) during the OHCA event for EMS-witnessed OHCA. Calls were reviewed by healthcare professionals using a survey guide.

RESULTS

Among 4,071 patients, 481 patients (12 %) had 539 calls within 24 hours prior to OHCA (60 % male, median age 74 years of age). The patient spoke on the phone in 25 % of calls. The most common symptoms were breathing problems (59 %), confusion (23 %), unconsciousness (20 %), chest pain (20 %), and paleness (19 %). Patients with breathing problems compared to chest pain were more likely to be ≤ 75 years of age (55 % versus 35 %), less likely to be male (52 % versus 73 %), have shockable rhythm (10 % versus 38 %), receive bystander defibrillation (6 % versus 19 %) or EMS defibrillation (15 % versus 65 %), achieve return of spontaneous circulation (37 % versus 68 %) and survive 30 days following OHCA (10 % versus 50 %).

CONCLUSION

More than 10% of patients with OHCA had a call to EMS within 24 hours before OHCA. The most common symptom was breathing problems which compared to chest pain had lower 30-day survival.

A Qualitative Analysis of the Experiences of EMS Clinicians in Recognizing and Treating Witnessed Cardiac Arrests

BACKGROUND

Survival from out of hospital cardiac arrest (OHCA) increases when effective cardiopulmonary resuscitation (CPR) and defibrillation are performed early. Patients who suffer OHCA in front of emergency medical services (EMS) clinicians have greater likelihood of survival, but little is known about how EMS clinicians think about and experience those events. We sought to understand how EMS clinicians assessed patients who devolved to cardiac arrest in their presence and uncover the perceived barriers and facilitators associated with recognizing and treating witnessed OHCAs.

METHODS

EMS clinicians who had attended an EMS-witnessed OHCA and consented to participate were interviewed within 72 hours of the index case. Transcripts of the interviews were coded through the consolidated framework for implementation research to understand enabling and constraining factors involved and the predictability and anticipation of OHCA and subsequent management of patient care. Utstein data points, interventions, and associated times were extracted from the medical records.

RESULTS

We interviewed 29 EMS clinicians who attended 27 EMS-witnessed OHCAs. Twenty-six (96.3%) of the EMS-witnessed OHCAs were preceded by prodromal symptoms and were classified as predictable. Of the predictable cases, clinicians anticipated 53.8% of them and attributed the prodromes of other cases to serious but not peri-arrest etiologies. Participants described various environmental, crew, and intrapersonal enabling and constraining factors associated with recognizing and treating EMS-witnessed OHCAs. Environmental elements included issues of safety and physical locations, crew elements included familiarity with their partners and working with them in the past, and intrapersonal elements included abilities to collect information and stress associated with responding to and managing the calls.

CONCLUSION

Recognition and treatment of EMS-witnessed OHCAs are influenced by numerous environmental, crew, and intrapersonal factors. Future training and education on OHCA should include diverse locations, situations, and crew make-up, along with nontraditional patient complaints to broaden experiences associated with cardiac arrest management.

The association between signs of medical distress preceding in-hospital cardiac arrest and 30-day survival – A register-based cohort study

Background

Identifying signs of medical distress prior to in-hospital cardiac arrest (IHCA) is important to prevent IHCA and improve survival. The primary objective of this study was to investigate the association between signs of medical distress present within 60 minutes prior to cardiac arrest and survival after cardiac arrest.

Methods

The register-based cohort study included adult patients (≥18 years) with IHCA in the Swedish Registry of Cardiopulmonary Resuscitation (SRCR) from 2017-01-01 to 2020–07-15. Signs of distress prior to IHCA were defined as the medical signs arrhythmia, pulmonary oedema, hypotension, hypoxia or seizures present within 60 minutes prior to cardiac arrest (pre-arrest signs). Using multivariable logistic regression, the association between these pre-arrest signs and 30-day survival was analysed in both unadjusted and adjusted models. The covariates used were demographics, comorbidities, characteristics and treatment of cardiac arrest.

Results

In total, 8525 patients were included. After adjusting for covariates, patients with arrhythmia had a 58% higher probability of 30-day survival. The adjusted probability of 30-day survival was 41% and 52% lower for patients with hypotension and hypoxia prior to IHCA, respectively. Pulmonary oedema and seizures were not associated with any change in 30-day survival.

Conclusions

Among signs of medical distress prior to in-hospital cardiac arrest, arrhythmia was associated with a higher 30-day survival. Hypotension and hypoxia were associated with lower survival after IHCA. These findings indicate that future research on survival after cardiac arrest should take pre-arrest signs into account as it impacts the prerequisites for survival.

Out-of-hospital cardiac arrest with onset witnessed by emergency medical services: Implications for improvement in overall survival

Out-of-hospital cardiac arrest (OHCA) remains a major public health problem. Even in high-income countries, survival rates have plateaued in the range of ten percent, stimulating an ongoing interest in developing novel approaches to resuscitation. Emergency Medical Services (EMS)-witnessed OHCAs constitute a subgroup of overall OHCA that occur after the arrival of EMS, leading to rapid initiation of resuscitation and significantly improved survival. In this narrative review we summarize and interpret recent developments in knowledge of EMS-witnessed OHCA regarding prevalence, demographics, location, circumstances, survival outcomes and clinical profile. We examine the possibility of informing novel resuscitation approaches and enhancing mechanistic knowledge by studying EMS-witnessed OHCA, with the goal of improving overall survival from OHCA.

Public knowledge and attitudes toward automated external defibrillators use among first aid eLearning course participants: a survey

Objective

Survival from out-of-hospital cardiac arrest (OHCA) often depends on the effective and immediate use of automated external defibrillators (AEDs). Given that there have been few studies about AED use in China, the purpose of this study is to investigate the knowledge and attitudes regarding AED use among the Chinese public, then provide an effective suggestion for AED education strategies and legislation.

Method

The online survey was conducted among Chinese participants of the First Aid eLearning courses in June 2020.

Result

A total of 2565 (95.00%) surveys were completed, only 23.46% of respondents with non-medical related respondents reported having attended previous AED training courses. Regarding the basic knowledge of AEDs, few respondents (12.28%, n = 315) could answer all four questions correctly. 95.67% (n = 2454) were willing to learn AED use. Even if without the precondition of being skilled in AEDs, the female was more likely to rescue OHCA patients than the male (p = 0.003). Almost all respondents (96.65%) showed a strong willingness to rescue OHCA patients with training in using AEDs. The top four barriers to rescuing OHCA patients were lack of practical performing ability (60.47%), fear of hurting patients (59.30%), inadequate knowledge of resuscitation techniques (44.19%), and worry about taking legal responsibility (26.74%).

Conclusion

Our study reflects a deficiency of AED knowledge among the general public in China. However, positive attitudes towards rescuing OHCA patients and learning AED use were observed, which indicates that measures need to be taken to disseminate knowledge and use of AEDs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13019-022-01863-1.

Global variation in the incidence and outcome of emergency medical services witnessed out-of-hospital cardiac arrest: A systematic review and meta-analysis

AIM OF THE REVIEW

To examine global variation in the incidence and outcomes of emergency medical services (EMS) witnessed out-of-hospital cardiac arrest (OHCA).

DATA SOURCES

We systematically reviewed four electronic databases for studies between 1990 and 5th April 2021 reporting EMS-witnessed OHCA populations. Studies were included if they reported sufficient data to calculate the primary outcome of survival to hospital discharge or 30-day survival. Random-effects models were used to pool incidence and survival outcomes, and meta-regression was used to examine sources of heterogeneity. Study quality was appraised using the Joanna Briggs Institute critical appraisal tools.

RESULTS

The search returned 1178 non-duplicate titles of which 66 articles comprising 133,981 EMS-witnessed patients treated by EMS across 33 countries were included. All but one study was observational and only 12 studies (18%) were deemed to be at low risk of bias. The pooled incidence of EMS-treated cases was 4.1 per 100,000 person-years (95% CI: 3.5, 4.7), varying almost 4-fold across continents. The pooled proportion of survivors to hospital discharge or 30-days was 20% overall (95% CI: 18%, 22%; I² = 98%), 43% (95% CI: 37%, 49%; I² = 94%) for initial shockable rhythms and 6% (95% CI: 5%, 8%; I² = 79%) for initial non-shockable rhythms. In the meta-regression analysis, only region and aetiology were significantly associated with survival. When compared to studies from North America, pooled survival was significantly higher in studies from Europe (14% vs. 26%; p = 0.04) and Australasia (14% vs. 31%, p < 0.001).

CONCLUSION

We identified significant global variation in the incidence and survival outcome of EMS-witnessed OHCA. Further research is needed to understand the factors contributing to these variations.

Seizure-like activity at the onset of emergency medical service-witnessed out-of-hospital cardiac arrest: An observational study

Aims

Emergency medical service (EMS) may detect seizure-like activity in addition to agonal breathing in out-of-hospital cardiac arrest (OHCA). This study investigates the incidence and predictors of seizure-like activity in nontraumatic, EMS-witnessed OHCA and their association with clinical outcomes.

Methods

This prospective study explored EMS-recorded concomitant signs/symptoms that lead to the requirement of advanced life support in patients with nontraumatic, EMS-witnessed OHCA. Seizure-like activity includes abnormal/tonic movements and eyeball deviation. Sudden OHCA was defined by the absence of signs/symptoms of impending cardiac arrest at EMS contact or progressive circulatory/respiratory depressions after the EMS contact. Neurologically favorable outcomes were defined as the cerebral performance category score of 1 or 2 at discharge.

Results

From April 2012 to March 2020, 465 patients were studied. The incidence of seizure-like activity at cardiac arrest onset was 12.7% (59/465) in all patients with nontraumatic, EMS-witnessed OHCA. Seizure-like activity was common during shockable initial rhythm; in patients with “sudden” OHCA; and in patients who were younger, male, or had a presumed cardiac etiology. In a boosting tree, shockable initial rhythm, “sudden” OHCA, and presumed cardiac etiology were major factors that predicted the incidence of seizure-like activity. Multivariate logistic regression models including and excluding OHCA characteristics revealed that both seizure-like activity and agonal breathing recorded during EMS-witnessed OHCA were associated with favorable outcomes.

Conclusions

Seizure-like activity is a major sign/symptom of the onset of “sudden” cardiac arrest of presumed cardiac etiology, particularly in patients with shockable initial rhythms. Such activity were significantly associated with neurologically favorable outcomes.

Survival outcomes in emergency medical services witnessed traumatic out-of-hospital cardiac arrest after the introduction of a trauma-based resuscitation protocol

AIM

In this study, we examine the impact of a trauma-based resuscitation protocol on survival outcomes following emergency medical services (EMS) witnessed traumatic out-of-hospital cardiac arrest (OHCA).

METHODS

We included EMS-witnessed OHCAs arising from trauma and occurring between 2008 and 2019. In December 2016, a new resuscitation protocol for traumatic OHCA was introduced prioritising the treatment of potentially reversible causes before conventional cardiopulmonary resuscitation. The effect of the new protocol on survival outcomes was assessed using adjusted multivariable logistic regression models.

RESULTS

Paramedics attempted resuscitation on 490 patients, with 341 (69.6%) and 149 (30.4%) occurring during the control and intervention periods, respectively. A reduction in the proportion of cases receiving cardiopulmonary resuscitation and epinephrine administration were found in the intervention period compared to the control period, whereas trauma-based interventions increased significantly, including blood administration (pre-arrest: 17.9% vs 3.7%; intra-arrest: 24.1% vs 2.7%), splinting (pre-arrest: 38.6% vs 17.1%; intra-arrest: 20.7% vs 5.2%), and finger thoracostomy (pre-arrest: 13.1% vs 0.6%; intra-arrest: 22.8% vs 0.9%), respectively, with p-values < 0.001 for all comparisons. After adjustment, the trauma-based resuscitation protocol was not associated with an improvement in survival to hospital discharge (AOR 1.29, 95% CI: 0.51-3.23), event survival (AOR 0.72, 95% CI: 0.41-1.28) or prehospital return of spontaneous circulation (AOR 0.63, 95% CI: 0.39-1.03).

CONCLUSION

In our region, the introduction of a trauma-based resuscitation protocol led to an increase in the delivery of almost all trauma interventions; however, this did not translate into better survival outcomes following EMS-witnessed traumatic OHCA.

Cardiac arrests in general practice clinics or witnessed by emergency medical services: a 20-year retrospective study

OBJECTIVE

To compare the frequency and outcomes of cardiac arrests in general practice clinics with those of paramedic-witnessed cardiac arrests.

DESIGN, SETTING

Retrospective study; analysis of Victorian Ambulance Cardiac Arrest Registry data, 1 January 2000 - 30 December 2019.

PARTICIPANTS

Patients with non-traumatic cardiac arrests whom emergency medical services staff attempted to resuscitate.

MAIN OUTCOME MEASURES

Survival to hospital discharge.

RESULTS

6363 cases of cardiac arrest were identified: 216 in general practice clinics (3.4%) and 6147 witnessed by paramedics (96.6%). The proportion of patients presenting with initial shockable rhythms was larger in clinic (126 patients, 58.3%) than paramedic-witnessed cases (1929, 31.4%). The proportion of general practice clinic cases in which defibrillation was provided in the clinic increased from 2 of 37 in 2000-2003 (5%) to 19 of 57 patients in 2016-2019 (33%); survival increased from 7 of 37 (19%) to 23 of 57 patients (40%). For patients with initial shockable rhythms, 57 of 126 in clinic cases (45%) and 1221 of 1929 people in paramedic-witnessed cases (63.3%) survived to hospital discharge; of 47 general practice patients defibrillated by clinic staff, 27 survived (57%). For patients with initial shockable rhythms, the odds of survival were greater following paramedic-witnessed events (adjusted odds ratio [aOR], 3.39; 95% CI, 2.08-5.54) or general clinic arrests with defibrillation by clinic staff (aOR, 2.23; 95% CI, 1.03-4.83) than for general practice clinic arrests in which arriving paramedics provided defibrillation.

CONCLUSION

Emergency medical services should be alerted as soon as possible after people experience heart attack warning symptoms. Automated external defibrillators should be standard equipment in general practice clinics, enabling prompt defibrillation, which may substantially reduce the risk of death for people in cardiac arrest.

Out-of-hospital cardiac arrest outcomes in emergency departments

BACKGROUND

The emergency department (ED) plays an important role in out-hospital-cardiac arrest (OHCA) management. However, ED outcomes are not widely reported. This study aimed to (1) describe OHCA ED outcomes and reasons for ED deaths, and (2) whether these differed between hospitals.

METHODS

Data were obtained from the Victorian Ambulance Cardiac Arrest Registry and 12 hospitals for adult, non-traumatic OHCA cases transported to ED between 2014 and 2016. Multivariable logistic regression was used to examine the association of level of cardiac arrest centre on ED survival in a subset of cases (non-paramedic witnessed OHCA who were unconscious on ED arrival with ROSC).

RESULTS

Of 1547 eligible OHCA cases, 81% (N = 1254) survived ED, varying between 57% to 88% between EDs. Among non-survivors, the majority had either: cessation of resuscitation after presenting with CPR in progress (27%); withdrawal of life-sustaining treatment for non-neurological (n = 65, 22%) or neurological (16%) reasons; or a unsuccessful resuscitation following a rearrested in ED (20%). These causes of ED deaths varied between the different levels of cardiac arrest centres, and in our subset of interest (n = 952) ED survival was associated with transportation to centres with high annual OHCA volumes and with 24-hour cardiac intervention capabilities (AOR = 3.43, 95% CI 1.89-6.21).

CONCLUSION

Our study found wide variation in survival between EDs, which was associated with hospital characteristics. Such data suggests the need for a detailed review of ED deaths, particularly in non-cardiac arrest centres, and potentially the need for monitoring ED survival as a measure of quality.

The EMS Modified Early Warning Score (EMEWS): A Simple Count of Vital Signs as a Predictor of Out-of-Hospital Cardiac Arrests

Objective: For patients at risk for out-of-hospital cardiac arrest (OHCA) after Emergency Medical Services (EMS) arrival, outcomes may be mitigated by identifying impending arrests and intervening before they occur. Tools such as the Modified Early Warning Score (MEWS) have been developed to determine the risk of arrest, but involve relatively complicated algorithms that can be impractical to compute in the prehospital environment. A simple count of abnormal vital signs, the "EMS Modified Early Warning Score" (EMEWS), may represent a more practical alternative. We sought to compare to the ability of MEWS and EMEWS to identify patients at risk for EMS-witnessed OHCA.Methods: We conducted a retrospect analysis of the 2018 ESO Data Collaborative database of EMS encounters. Patients without cardiac arrest before EMS arrival were categorized into those who did or did not have an EMS-witnessed arrest. MEWS was evaluated without its temperature component (MEWS-T). The performance of MEWS-T and EMEWS in predicting EMS witnessed arrest was evaluated by comparing receiver-operating characteristic curves.Results: Of 369,064 included encounters, 4,651 were EMS witnessed arrests. MEWS-T demonstrated an area under the curve (AUC) of 0.79 (95% CI: 0.79 - 0.80), with 86.8% sensitivity and 51.0% specificity for MEWS-T ≥ 3. EMEWS demonstrated an AUC of 0.74 (95% CI: 0.73 - 0.75), with 81.3% sensitivity and 53.9% specificity for EMEWS ≥ 2.Conclusions: EMEWS showed a similar ability to predict EMS-witnessed cardiac arrest compared to MEWS-T, despite being significantly simpler to compute. Further study is needed to evaluate whether the implementation of EMEWS can aid EMS clinicians in anticipating and preventing OHCA.

Risk prediction models for out-of-hospital cardiac arrest outcomes in England

AIMS

The out-of-hospital cardiac arrest (OHCA) outcomes project is a national research registry. One of its aims is to explore sources of variation in OHCA survival outcomes. This study reports the development and validation of risk prediction models for return of spontaneous circulation (ROSC) at hospital handover and survival to hospital discharge.

METHODS AND RESULTS

The study included OHCA patients who were treated during 2014 and 2015 by emergency medical services (EMS) from seven English National Health Service ambulance services. The 2014 data were used to identify important variables and to develop the risk prediction models, which were validated using the 2015 data. Model prediction was measured by area under the curve (AUC), Hosmer-Lemeshow test, Cox calibration regression, and Brier score. All analyses were conducted using mixed-effects logistic regression models. Important factors included age, gender, witness/bystander cardiopulmonary resuscitation (CPR) combined, aetiology, and initial rhythm. Interaction effects between witness/bystander CPR with gender, aetiology and initial rhythm and between aetiology and initial rhythm were significant in both models. The survival model achieved better discrimination and overall accuracy compared with the ROSC model (AUC = 0.86 vs. 0.67, Brier score = 0.072 vs. 0.194, respectively). Calibration tests showed over- and under-estimation for the ROSC and survival models, respectively. A sensitivity analysis individually assessing Index of Multiple Deprivation scores and location in the final models substantially improved overall accuracy with inconsistent impact on discrimination.

CONCLUSION

Our risk prediction models identified and quantified important pre-EMS intervention factors determining survival outcomes in England. The survival model had excellent discrimination.

Impact of a public awareness campaign on out-of-hospital cardiac arrest incidence and mortality rates

Aims

Increased public awareness of the warning signs of a heart attack and the importance of early medical intervention may help to prevent premature deaths from out-of-hospital cardiac arrest (OHCA). We sought to investigate the impact of the Heart Foundation's public awareness campaigns on the monthly incidence of, and deaths from, OHCA in Melbourne, Australia.

Methods and results

Between July 2005 and June 2015, we included registry data for 25 060 OHCA of presumed cardiac aetiology. Time series models with distributed lags were used to explore the effect of campaign activity on OHCA outcomes. A sensitivity analysis involving segmented regression of the pre-intervention, intervention, and post-intervention time segments was also performed. The mean monthly incidence of, and deaths from, OHCA was 207 and 189 events respectively. After adjustment for temporal trends, campaign activity was associated with a 6.0% [95% confidence interval (CI): 2.8-9.0%; P < 0.001] reduction in the monthly incidence of OHCA, or 11.7% (95% CI: 7.7-15.5%, P < 0.001) with the addition of residual effects in two additional lag months. Similarly, the rate of deaths from OHCA reduced by 6.4% (95% CI: 2.8-10.0%; P = 0.001) during months with campaign activity. Campaign activity had a greater effect in males and patients aged ≥65 years, and reduced the incidence of OHCA in unwitnessed and initial non-shockable arrests. In the segmented regression analysis, the intervention period was associated with a 15.2% (95% CI: 9.2-20.9%; P < 0.001) reduction in the mean monthly incidence and a 16.6% (95% CI: 9.9-22.7%; P < 0.001) reduction in deaths from OHCA.

Conclusion

A comprehensive mass media campaign targeting the community's awareness of heart attack symptoms was associated with a substantial reduction in the incidence of OHCA and associated deaths.

Importance of comorbidities in comatose survivors of shockable and non-shockable out-of-hospital cardiac arrest treated with target temperature management

OBJECTIVE

Comorbidity prior to out-of-hospital cardiac arrest (OHCA) and primary rhythm in relation to survival is not well established. We aimed to assess the prognostic importance of comorbidity in relation to primary rhythm in OHCA-patients treated with Target Temperature Management (TTM).

DESIGN

Consecutive comatose survivors of OHCA treated with TTM in hospitals in the Copenhagen area between 2002-2011 were included. Utstein-based pre- and in-hospital data collection was performed. Data on comorbidity was obtained from The Danish National Patient Register and patient charts, assessed by the Charlson Comorbidity Index (CCI).

RESULTS

A total of 666 patients were included. A third (n = 233, 35%) presented with non-shockable rhythm, and they were less often male (64% vs. 82%, p < .001), and OHCA in public, witnessed OHCA, and bystander cardiopulmonary resuscitation (CPR) were less common compared to patients with a shockable primary rhythm (public: 27% vs. 48%, p < .001, witnessed: 79% vs. 90%, p < .001, bystander CPR: 47% vs. 63%, p < .001). 30-day mortality was 62% compared to 28% in patients with non-shockable and shockable rhythm, respectively. By Cox-regression analyses, any comorbidity (CCI ≥1) was the only factor independently associated with 30-day mortality in patients with non-shockable rhythm (HR =1.9 (95% CI: 1.2-2.9), p < .01), whereas in patients with shockable rhythm comorbidity was not associated with outcome after adjustment for prognostic factors (HR = 0.82 (0.55-1.2), p = .34). No significant interaction between primary rhythm and comorbidity in terms of mortality was present.

CONCLUSION

A higher comorbidity burden was independently associated with a higher 30-day mortality rate in patients presenting with non-shockable primary rhythm but not in patients with shockable rhythm.

The significance of strong ion gap for predicting return of spontaneous circulation in patients with cardiopulmonary arrest

Useful parameters that can predict return of spontaneous circulation (ROSC) in patients with cardiopulmonary arrest (CPA) have not been established. We previously reported the usefulness of anion gap (AG) and albumin-corrected anion gap (ACAG) calculated from a blood sample obtained on arrival at the hospital for the prediction of ROSC. Otherwise, it has been reported that strong ion gap (SIG), which shows the difference between the levels of fully dissociated cations and anions in the serum, is useful to predict the prognosis of critically ill patients.

This was a prospective and observational clinical study. Patients with CPA transferred to the emergency department of our hospital between January 2013 and December 2014 were evaluated. Patients were divided into two groups: patients who obtained ROSC [ROSC(+) group] and those who did not [ROSC(−) group]. We compared AG, ACAG and SIG between the two groups.

A total of 170 patients were enrolled. Fifty patients were included in the ROSC(+) group, and the remaining 120 in the ROSC(−) group. Both AG and ACAG were significantly better in the ROSC(+) group; however, there was no significant difference in SIG between the two groups. The area under the receiver operating characteristic curves (AUC) for ROSC of both AG and ACAG were almost the same (0.72 and 0.708, respectively); the AUC of SIG (0.57) was inferior to those of AG and ACAG.

Our results suggest that AG and ACAG can better predict ROSC following cardiopulmonary resuscitation (CPR) compared with SIG.

Location of cardiac arrest and impact of pre-arrest chronic disease and medication use on survival

INTRODUCTION

Cardiac arrest in a private location is associated with a higher mortality when compared to public location. Past studies have not accounted for pre-arrest factors such as chronic disease and medication.

AIM

To investigate whether the association between cardiac arrest in a private location and a higher mortality can be explained by differences in chronic diseases and medication.

METHODS

We identified 27,771 out-of-hospital cardiac arrest patients ≥18 years old from the Danish Cardiac Arrest Registry (2001-2012). Using National Registries, we identified pre-arrest chronic disease and medication. To investigate the importance of cardiac arrest related factors and chronic disease and medication use we performed adjusted Cox regression analyses during day 0-7 and day 8-365 following cardiac arrest to calculate hazard ratios (HR) for death.

RESULTS

Day 0-7: Un-adjusted HR for death day 0-7 was 1.21 (95%CI:1.18-1.25) in private compared to public location. When including cardiac arrest related factors HR for death was 1.09 (95%CI:1.06-1.12). Adding chronic disease and medication to the analysis changed HR for death to 1.08 (95%CI:1.05-1.12). 8-365 day: The un-adjusted HR for death day 8-365 was 1.70 (95% CI: 1.43-2.02) in private compared to public location. When including cardiac arrest related factors the HR decreased to 1.39 (95% CI: 1.14-1.68). Adding chronic disease and medication to the analysis changed HR for death to 1.27 (95% CI:1.04-1.54).

CONCLUSION

The higher mortality following cardiac arrest in a private location is partly explained by a higher prevalence of chronic disease and medication use in patients surviving until day 8.

Determinants of unfavorable prognosis for out-of-hospital sudden cardiac arrest in Bielsko-Biala district

INTRODUCTION

The prognosis in out-of-hospital sudden cardiac arrest (OHCA) remains unfavorable and depends on a number of demographic and clinical variables, the reversibility of its causes and its mechanisms.

AIM

To investigate the risk factors of prehospital death in patients with OHCA in Bielsko County.

MATERIAL AND METHODS

The study analyzed all dispatch cards of the National Emergency Medical Services (EMS) teams in Bielsko-Biala for the year 2013 (n = 23 400). Only the cards related to sudden cardiac arrest in adults were ultimately included in the study (n = 272; 190 men, 82 women; median age: 71 years).

RESULTS

Sixty-seven victims (45 men, 22 women) were pronounced dead upon the arrival of the EMS team, and cardiopulmonary resuscitation (CPR) was not undertaken. In the remaining group of 205 subjects, CPR was commenced but was ineffective in 141 patients (97 male, 44 female). Although univariate analysis indicated 6 predictors of prehospital death, including OHCA without the presence of witnesses (odds ratio (OR) = 4.2), OHCA occurring in a public place (OR = 3.1), no bystander CPR (OR = 9.7), no bystander cardiac massage (OR = 13.1), initial diagnosis of non-shockable cardiac rhythm (OR = 7.0), and the amount of drugs used for CPR (OR = 0.4), logistic regression confirmed that only the lack of bystander cardiac massage (OR = 6.5) and non-shockable rhythm (OR = 4.6) were independent determinants of prehospital death (area under ROC curve = 0.801).

CONCLUSIONS

Non-shockable rhythm of cardiac arrest and lack of bystander cardiac massage are independent determinants of prehospital death in Bielsko-Biala inhabitants suffering from OHCA.

Impact of cardiopulmonary resuscitation duration on survival from paramedic witnessed out-of-hospital cardiac arrests: An observational study

BACKGROUND

Resuscitation guidelines often recommend ongoing cardiopulmonary resuscitation (CPR) efforts to hospital for out-of-hospital cardiac arrests (OHCA) witnessed by emergency medical service (EMS) personnel. In this study, we examine the relationship between EMS CPR duration and survival to hospital discharge in EMS witnessed OHCA patients.

METHODS

Between January 2003 and December 2011, 1035 adult EMS witnessed arrests of presumed cardiac aetiology were included from the Victorian Ambulance Cardiac Arrest Registry. CPR duration was defined as the total sum of prehospital CPR time in minutes. Adjusted logistic regression analyses were used to assess the impact of EMS CPR duration on survival to hospital discharge.

RESULTS

382 (37.3%) patients were discharged alive. The median CPR duration was 12 min (95% CI: 11-13) overall, but was higher in non-survivors compared to survivors (24 min vs. 2 min, p<0.001). The 99th percentile CPR duration in patients surviving to hospital discharge differed by the initial rhythm of arrest: 32 min (95% CI: 27-44) overall, 32 min (95% CI: 23-44) for ventricular fibrillation and pulseless ventricular tachycardia (VF/VT), 34 min (95% CI: 30-34) for pulseless electrical activity (PEA), and 28 min (95% CI: 21-28) for asystole. There were no survivors after 44 min for all rhythms. After adjusting for prehospital confounders, every minute increase in CPR duration was associated with a 13% reduction in the odds of survival to hospital discharge (OR 0.87, 95% CI: 0.84-0.89, p<0.001). The multivariable model predicted no chance of survival at or after a CPR duration of 48 min for VF/VT patients, 47 min for PEA patients and 45 min for asystole patients.

CONCLUSION

Resuscitation efforts exceeding 32 min yielded less than 1% of survivors from EMS witnessed OHCA. On the basis of this data, EMS witnessed OHCA patients may benefit from ongoing CPR efforts up to 48 min in duration.

The UK Out of Hospital Cardiac Arrest Outcome (OHCAO) project

INTRODUCTION

Reducing premature death is a key priority for the UK National Health Service (NHS). NHS Ambulance services treat approximately 30 000 cases of suspected cardiac arrest each year but survival rates vary. The British Heart Foundation and Resuscitation Council (UK) have funded a structured research programme--the Out of Hospital Cardiac Arrest Outcomes (OHCAO) programme. The aim of the project is to establish the epidemiology and outcome of OHCA, explore sources of variation in outcome and establish the feasibility of setting up a national OHCA registry.

METHODS AND ANALYSIS

This is a prospective observational study set in UK NHS Ambulance Services. The target population will be adults and children sustaining an OHCA who are attended by an NHS ambulance emergency response and where resuscitation is attempted. The data collected will be characterised broadly as system characteristics, emergency medical services (EMS) dispatch characteristics, patient characteristics and EMS process variables. The main outcome variables of interest will be return of spontaneous circulation and medium-long-term survival (30 days to 10-year survival).

ETHICS AND DISSEMINATION

Ethics committee permissions were gained and the study also has received approval from the Confidentiality Advisory Group Ethics and Confidentiality committee which provides authorisation to lawfully hold identifiable data on patients without their consent. To identify the key characteristics contributing to better outcomes in some ambulance services, reliable and reproducible systems need to be established for collecting data on OHCA in the UK. Reports generated from the registry will focus on data completeness, timeliness and quality. Subsequent reports will summarise demographic, patient, process and outcome variables with aim of improving patient care through focus quality improvement initiatives.

The prevalence and significance of abnormal vital signs prior to in-hospital cardiac arrest

BACKGROUND

Patients suffering in-hospital cardiac arrest often show signs of physiological deterioration before the event. The purpose of this study was to determine the prevalence of abnormal vital signs 1-4h before cardiac arrest, and to evaluate the association between these vital sign abnormalities and in-hospital mortality.

METHODS

We included adults from the Get With the Guidelines(®)- Resuscitation registry with an in-hospital cardiac arrest. We used two a priori definitions for vital signs: abnormal (heart rate (HR) ≤ 60 or ≥ 100 min(-1), respiratory rate (RR) ≤ 10 or >20 min(-1) and systolic blood pressure (SBP) ≤ 90 mm Hg) and severely abnormal (HR ≤ 50 or ≥ 130 min(-1), RR ≤ 8 or ≥ 30 min(-1) and SBP ≤ 80 mm Hg). We evaluated the association between the number of abnormal vital signs and in-hospital mortality using a multivariable logistic regression model.

RESULTS

7851 patients were included. Individual vital signs were associated with in-hospital mortality. The majority of patients (59.4%) had at least one abnormal vital sign 1-4h before the arrest and 13.4% had at least one severely abnormal sign. We found a step-wise increase in mortality with increasing number of abnormal vital signs within the abnormal (odds ratio (OR) 1.53 (CI: 1.42-1.64) and severely abnormal groups (OR 1.62 (CI: 1.38-1.90)). This remained in multivariable analysis (abnormal: OR 1.38 (CI: 1.28-1.48), and severely abnormal: OR 1.40 (CI: 1.18-1.65)).

CONCLUSION

Abnormal vital signs are prevalent 1-4h before in-hospital cardiac arrest on hospital wards. In-hospital mortality increases with increasing number of pre-arrest abnormal vital signs as well as increased severity of vital sign derangements.