Occurrence of shockable rhythm in out-of-hospital cardiac arrest over time: A report from the COSTA group

The physiology and potential of spectral amplitude area (AMSA) as a guide for resuscitation

Many studies aimed at understanding the electrophysiological mechanisms of ventricular fibrillation (VF) and defibrillation. Although many theories have been proposed about VF, we are still far from fully understanding it. Research has revealed significant insights provided by VF waveform, particularly through its amplitude of spectral area (AMSA). In fact, by potentially representing the energetic status of myocardial cells, AMSA has been shown in both animal and human studies to be a predictor of defibrillation success, return of spontaneous circulation (ROSC), early and long-term survival, and the presence of coronary artery disease underlying the cardiac arrest. The routine use of AMSA in the field could significantly improve resuscitation efforts and lead to a more advanced resuscitation technique by aiding in the selection of the appropriate timing and energy for defibrillation. The aim of this review is to explore what AMSA is and how real-time AMSA use could improve resuscitation directly from the field. If proven to improve patient outcomes, AMSA could significantly transform resuscitation practices, enabling more precise defibrillation strategies and enhanced patient survival.

Cost-effectiveness of a community first responder system for out-of-hospital cardiac arrest in Belgium

OBJECTIVE

Out-of-hospital cardiac arrest (OHCA) is a major public health challenge across Europe, with a survival rate of only 8.5% to hospital discharge. Implementing a community first responder (CFR) system, including earlier Basic Life Support and defibrillation, can enhance survival rates and neurological outcomes. This study assesses the cost-effectiveness of two scenarios for implementing such a system in Belgium.

METHODS

A decision tree and the long-term Markov model were used to evaluate cost-effectiveness by comparing two scenarios with current care standards. Scenario 1 involved an awareness campaign on OHCA, while Scenario 2 included implementing a CFR system with automated external defibrillator (AED) integration, dispatch centre linkage and training for citizen responders. The analysis covered survival to the emergency department, hospital, discharge and neurologically intact survival, with sensitivity analyses to test robustness.

RESULTS

The awareness campaign and implementation of the CFR system resulted in an incremental cost-effectiveness ratio of €14,976 and €16,442 per quality-adjusted life year gained for scenarios 1 and 2, respectively. Both scenarios showed improvements in survival rates at various stages, including hospital discharge and neurologically intact survival.

CONCLUSION

This study highlights the benefits of enhancing Belgium's CFR for OHCA patients. It suggests that accessible AEDs, trained CFRs and an integrated emergency response system could improve survival rates and quality of life. These findings can guide policy and resource decisions, potentially improving the effectiveness and cost-efficiency of OHCA emergency services. Additionally, this approach could serve as a model for other regions aiming to strengthen their response to time-sensitive emergencies.

What's the cardiac rhythm at the time of cardiac arrest? Disputed dogma or true fact?

It was widely accepted that malignant ventricular arrhythmias (VA) are the main direct initial cause for cardiac arrest and sudden cardiac death (SCD), but diverging data tended to demonstrate that asystole or pulseless activity were becoming the most prevalent cardiac rhythms at the time of cardiac arrest. We challenge here these conceptions and reinforce the persisting prominent role of VA in SCD.

Assessing Key Factors Influencing Successful Resuscitation Outcomes in Out-of-Hospital Cardiac Arrest (OHCA)

Background: Out-of-hospital cardiac arrest (OHCA) is a critical health issue with survival influenced by multiple factors. This study analyzed resuscitation outcomes at the County Clinical Emergency Hospital of Sibiu, Romania, during pre-COVID-19 and pandemic periods. Methods: A retrospective analysis of 508 OHCA patients (2017-2020) assessed the return of spontaneous circulation (ROSC) as the primary endpoint. Statistical methods included decision tree analysis, logistic regression and ROC curve analysis to evaluate the predictive value of adrenaline dose and patient factors. Results: The mortality rate was 68.7%, with non-shockable rhythms predominant among fatalities. Rural patients, though younger, had lower ROSC rates than urban counterparts. Logistic regression showed that lower adrenaline doses (≤4 mg, OR 11.835 [95% CI: 6.726-20.27]; 4-6 mg, OR 2.990 [95% CI: 1.773-5.042]) were associated with better ROSC outcomes. Conclusions: A multivariable model (AUC = 0.773) incorporating demographics and pandemic status outperformed adrenaline dose alone (AUC = 0.711).

Out-of-hospital cardiac arrest in Bahrain: National retrospective cohort study

Aim

There is limited research on Out-of-hospital cardiac arrest (OHCA) in the Gulf Cooperation Council (GCC) and especially in Bahrain. This is the first study to describe the incidence, characteristics, and outcomes of OHCA in Bahrain.

Methods

This was a retrospective national observational study on OHCA patients in Bahrain using the Utstein framework for resuscitation. Data was collected between 1st July 2022 to 30th June 2023 from the electronic medical records of the only three governmental hospitals emergency departments (EDs) and National Ambulance (NA).

Results

The annual incidence of OHCA attended by (Emergency Medical Services) EMS was nearly 21 per 100,000 population. The majority were males (n = 228, 68.8 %) with median age of 65 years (IQR=49-78). Most OHCA cases were witnessed (n = 265, 81 %), with (n = 247, 76 %) happened at home/residence. Rates for bystander CPR was low (n = 122, 36.8 %) and bystander automated external defibrillator (AED) was not performed in any of the cases. The OHCA cases transported by the NA was (n = 314, 94.8 %), with median response time of 9 min (IQR=7-12). However, only (n = 20, 6.0 %) were witnessed by EMS, and (n = 7, 2.1 %) received EMS defibrillation for shockable rhythms. First monitored rhythms included shockable rhythm in (n = 28, 8.5 %) versus non-shockable rhythm in (n = 303, 91.5 %). In the EDs, return of spontaneous circulation was achieved in (n = 60, 18.1 %) cases. But survival rate to hospital discharge at 30-day was (n = 4, 1.2 %) and survival rate to hospital discharge with good neurological outcomes was (n = 0, 0 %). Conclusion: In Bahrain the estimated annual incidence of OHCA is 21 individuals per 100,000 population, with a very low survival rate. Solutions should focus on community-level CPR and AED training, evaluating OHCA care provided by EMS, and establishing OHCA registry.

Early prehospital mechanical cardiopulmonary resuscitation use for out-of-hospital cardiac arrest: an observational study

BACKGROUND

The use of mechanical cardiopulmonary resuscitation device has been very prevalent in out-of-hospital cardiac arrest rescue. This study aimed to investigate whether the timing of mechanical cardiopulmonary resuscitation device set-up correlated with the the outcome of cardiac arrest patients.

METHODS

We retrospectively reviewed adult nontrauma cardiac arrest cases in New Taipei City, Taiwan, from January to December 2022. Demographic data, intervention-related factors, and the time variables of mechanical cardiopulmonary resuscitation were collected. The outcomes included the return of spontaneous circulation and 24-hour survival. We compared patients who achieved spontaneous circulation and those who did not with univariate and multivariable regression analyses.

RESULTS

In total, 1680 patients who received mechanical cardiopulmonary resuscitation were included in the analysis. Reducing the time interval from manual chest compression initiation to device setup was independently associated with the return of spontaneous circulation and 24-hour survival, especially in the subgroup of patients of initial shockable rhythm. Receiver operating characteristic analysis revealed that the outcome of patients with an initial shockable rhythm could be predicted by the mechanical cardiopulmonary resuscitation setup time, with areas under the curve of 60.8% and 63.9% for ROSC and 24-hour survival, respectively. The cutoff point was 395.5 s for patients with an initial shockable rhythm.

CONCLUSION

A positive correlation was found between early mechanical cardiopulmonary resuscitation intervention and the outcomes of out-of-hospital cardiac arrest patients. The time between manual chest compression and device setup could predict the return of spontaneous circulation and 24-hour survival in the subgroup of patients with initially shockable rhythm with the optimal cutoff point at 395.5 s.

Circadian variation pattern of sudden cardiac arrest occurred in Chinese community

BACKGROUND

The circadian variation pattern of sudden cardiac arrest (SCA) occurred in Chinese community including both community healthcare centres and primary hospitals remains unknown. This study analysed the circadian variation of SCA in the Chinese community.

METHODS

Data between 2018 and 2022 from the remote ECG diagnosis system of Xinhua Hospital affiliated to Shanghai Jiao Tong University School of Medicine were analysed to examine the circadian rhythm of SCA, stratified by initial shockable (ventricular tachycardia or ventricular fibrillation) versus non-shockable (asystole or pulseless electrical activity) rhythm.

RESULTS

Among 10 210 cases of SCA, major cases (8736, 85.6%) were non-shockable and 1474 (14.4%) cases were shockable. The circadian rhythm of SCA was as follows: peak time was from 08:00 to 11:59 (30.1%), while deep valley was from 00:00 to 03:59 (7.5%). The proportions of events by non-shockable and shockable events were similar and both reached their peak from 08:00 to 11:59, with a percentage of 29.0% and 36.4%, respectively. Multivariable analysis showed that the relative risk of shockable compared with non-shockable arrests was lower between 00:00 and 03:59 (adjusted OR (aOR): 0.72, 95% CI: 0.54 to 0.97, p=0.028) and 04:00 to 07:59 (aOR: 0.60, 95% CI: 0.46 to 0.79, p<0.001), but higher between 08:00 and 11:59 (aOR: 1.34, 95% CI: 1.09 to 1.64, p=0.005).

CONCLUSIONS

In Chinese community, there is a distinct circadian rhythm of SCA, regardless of initial rhythms. Our findings may be helpful in decision-making, in that more attention and manpower should be placed on the morning hours of first-aid and resuscitation management in Chinese community.

Sex and 30-day survival following out-of-hospital cardiac arrest in Scotland 2011-2020

BACKGROUND

Differences in 30-day survival between males and females following out-of-hospital cardiac arrest (OHCA) are well documented. Biological sex does not appear to be responsible for this survival gap independently of potential mediating factors. We investigated the role of potential mediating factors in the association between sex and 30-day survival after OHCA in Scotland.

METHODS

A retrospective cohort study of adult non-emergency medical services (EMS)-witnessed OHCA cases was conducted. We included incidents from the whole of Scotland where resuscitation was attempted by the Scottish Ambulance Service (SAS) between April 1, 2011 and March 1, 2020. Logistic regression was used to assess the contribution of age, socioeconomic status, urban-rural location of the incident, initial cardiac rhythm, bystander cardiopulmonary resuscitation (CPR) and location of the arrest (home or away from home).

RESULTS

The cohort consisted of 20,585 OHCA cases (13,130 males and 7,455 females). Median (IQR) age was 69 years (22) for males versus 72 years (23) for females. A higher proportion of males presented with initial shockable rhythm (29.4% versus 12.4%) and received bystander CPR (56.7% versus 53.2%) compared with females. A higher proportion of females experienced OHCA at home (78.8% versus 66.8%). Thirty-day survival after OHCA was higher for males compared with females (8.2% versus 6.2%). Males had higher age-adjusted odds for 30-day survival after OHCA than females (OR, 1.26; (95% CI), 1.12-1.41). Mediation analyses suggested a role for initial cardiac rhythm and location of the arrest (home or away from home).

CONCLUSION

Males had higher age-adjusted 30-day survival after OHCA than females. However, after adjusting for confounding/mediating variables, sex was not associated with 30-day survival after OHCA. Our findings suggest that initial cardiac rhythm and location of the arrest are potential mediators of higher 30-day OHCA survival in males than females. Improving proportions of females who present with initial shockable rhythm may reduce sex differences in survival after OHCA.

Dispatcher nurses' experiences of handling drones equipped with automated external defibrillators in suspected out-of-hospital cardiac arrest - a qualitative study

BACKGROUND

Reducing the time to treatment by means of cardiopulmonary resuscitation (CPR) and defibrillation is essential to increasing survival after cardiac arrest. A novel method of dispatching drones for delivery of automated external defibrillators (AEDs) to the site of a suspected out-of-hospital cardiac arrest (OHCA) has been shown to be feasible, with the potential to shorten response times compared with the emergency medical services. However, little is known of dispatchers' experiences of using this novel methodology.

METHODS

A qualitative semi-structured interview study with a phenomenological approach was used. Ten registered nurses employed at an emergency medical dispatch centre in Gothenburg, Sweden, were interviewed and the data was analysed by qualitative content analysis. The purpose was to explore dispatcher nurses' experiences of deliveries of AEDs by drones in cases of suspected OHCA.

RESULTS

Three categories were formed. Nurses expressed varying compliance to the telephone-assisted protocol for dispatch of AED-equipped drones. They experienced uncertainty as to how long would be an acceptable interruption from the CPR protocol in order to retrieve a drone-delivered AED. The majority experienced that collegial support was important. Technical support, routines and training need to be improved to further optimise action in cases of drone-delivered AEDs handled by dispatcher nurses.

CONCLUSIONS

Although telephone-assisted routines for drone dispatch in cases of OHCA were available, their use was rare. Registered nurses showed variable degrees of understanding of how to comply with these protocols. Collegial and technical support was considered important, alongside routines and training, which need to be improved to further support bystander use of drone-delivered AEDs. As the possibilities of using drones to deliver AEDs in cases of OHCA are explored more extensively globally, there is a good possibility that this study could be of benefit to other nations implementing similar methods. We present concrete aspects that are important to take into consideration when implementing this kind of methodology at dispatch centres.

Early Enteral Nutrition Could Be Associated with Improved Survival Outcome in Cardiac Arrest

Background

Although the latest European and US guidelines recommend that early enteral nutrition (EN) be attempted in critically ill patients, there is still a lack of research on feeding strategies for patients after cardiac arrest (CA). Due to the unique pathophysiology following CA, it remains unknown whether evidence from other diseases can be applied in this condition.

Objective

We aimed to explore the relationship between the timing of EN (within 48 hours or after 48 hours) and clinical outcomes and safety in CA.

Method

From the MIMIC-IV (version 2.2) database, we conducted this retrospective cohort study. A 1 : 1 propensity score matching (PSM) analysis was also conducted to prevent potential interference from confounders. Moreover, adjusted proportional hazards model regression models were used to adjust for prehospital and hospitalization characteristics to verify the independence of the association between early EN initiation and patient outcomes.

Results

Of the initial 1286 patients, 670 were equally assigned to the early EN or delayed EN group after PSM. Patients in the early EN group had improved survival outcomes than those in the delayed EN group within 30 days (HR = 0.779, 95% confidence interval [CI] [0.611-0.994], p = 0.041). Similar results were shown at 90 and 180 days. However, there was no significant difference in neurological outcome between the two groups at 30 days (51% vs. 57%, odds ratio [OR] = 0.786, 95% CI [0.580-1.066], p = 0.070). Patients who underwent early EN had a lower risk of ileus than patients who underwent delayed EN (4% vs. 8%, OR = 0.461, 95% CI [0.233-0.909], p = 0.016). Moreover, patients who underwent early EN had shorter hospital stays.

Conclusion

Early EN could be associated with improved survival outcomes for patients after CA. Further studies are needed to verify it. However, at present, we might consider early EN to be a more suitable feeding strategy for CA.

Association Between QRS Characteristics in Pulseless Electrical Activity and Survival Outcome in Cardiac Arrest Patients: A Systematic Review and Meta-Analysis

OBJECTIVE

Recent studies have shown inconsistent results regarding the association between QRS characteristics and survival outcomes in patients with cardiac arrest and pulseless electrical activity (PEA) rhythms. This meta-analysis aimed to identify the usefulness of QRS width and frequency as prognostic tools for outcomes in patients with cardiac arrest and PEA rhythm.

METHODS

Extensive searches were conducted using Medline, Embase, and the Cochrane Library to find articles published from database inception to 4 June 2023. Studies that assessed the association between the QRS characteristics of cardiac arrest patients with PEA rhythm and survival outcomes were included. The Newcastle-Ottawa Scale was used to assess the methodological quality of the included studies.

RESULTS

A total of 9727 patients from seven observational studies were included in this systematic review and meta-analysis. The wide QRS group (QRS ≥ 120 ms) was associated with significantly higher odds of mortality than the narrow QRS group (QRS < 120 ms) (odds ratio (OR) = 1.86, 95% confidence interval (CI) = 1.11-3.11, I2 = 58%). The pooled OR for mortality was significantly higher in patients with a QRS frequency of < 60/min than in those with a QRS frequency of ≥ 60/min (OR = 1.90, 95% CI = 1.19-3.02, I2 = 65%).

CONCLUSIONS

Wide QRS width or low QRS frequency is associated with increased odds of mortality in patients with PEA cardiac arrest. These findings may be beneficial to guide the disposition of cardiac arrest patients with PEA during resuscitation.

Resuscitation for out-of-hospital cardiac arrest in Ireland 2012-2020: Modelling national temporal developments and survival predictors

Aim

To explore potential predictors of national out-of-hospital cardiac arrest (OHCA) survival, including health system developments and the COVID pandemic in Ireland.

Methods

National level OHCA registry data from 2012 through to 2020, relating to unwitnessed, and bystander witnessed OHCA were interrogated. Logistic regression models were built by including predictors through stepwise variable selection and enhancing the models by adding pairwise interactions that improved fit. Missing data sensitivity analyses were conducted using multiple imputation.

Results

The data included 18,177 cases. The final model included seventeen variables. Of these nine variables were involved in pairwise interactions. The COVID-19 period was associated with reduced survival (OR 0.61, 95%CI 0.43, 0.87), as were increasing age in years (OR 0.96, 95% CI 0.96, 0.97) and call response interval in minutes (OR 0.97, 95% CI 0.96, 0.99). Amiodarone administration (OR 3.91, 95% CI 2.80, 5.48), urban location (OR 1.40, 95% CI 1.12, 1.77), and chronological year over time (OR 1.14, 95% CI 1.08, 1.20) were associated with increased survival.

Conclusions

National survival from OHCA has significantly increased incrementally over time in Ireland. The COVID-19 pandemic was associated with decreased survival even after accounting for potential disruption to key elements of bystander and EMS care. Further research is needed to understand and address the discrepancy between urban and rural OHCA survival. Information concerning pre-event patient health status and inpatient care process may yield important additional insights in future.

Economic evaluation of automated external defibrillator deployment in public settings for out-of-hospital cardiac arrest: a systematic review

BACKGROUND

Out-of-hospital cardiac arrest (OHCA) is a major issue in aging populations. The use of automatic external defibrillators (AEDs) in public places improves cardiac arrest survival rates. The purpose of this study is to review economic evaluation studies of the use of AED technology in public settings for cardiac arrest resuscitation.

METHODS

Our search covered 1990-2021 and included PubMed, Cochrane Library, Embase, Scopus, and Web of Science. We included studies that analyzed cost-effectiveness, cost-utility and cost-benefit of the AED technology. Also, we performed the quality assessment of the studies through the checklist of quality assessment standard of health economic studies (QHES).

RESULTS

Our inclusion criteria were met by 25 studies. AEDs are found to be cost-effective in places with a high occurrence of cardiac arrest. In addition, proper integration of drones with AEDs into existing systems has the potential to significantly improve OHCA survival rates.

CONCLUSION

The present study found that putting AEDs in high-cardiac arrest and crowded areas reduces average costs. Despite this, the costs associated with acquiring and maintaining AEDs prevent their widespread use. Further research is needed to evaluate feasibility and explore innovative strategies for AED maintenance and accessibility.

Cardiorespiratory Sensors and Their Implications for Out-of-Hospital Cardiac Arrest Detection: A Systematic Review

Out-of-hospital cardiac arrest (OHCA) is a major health problem, with a poor survival rate of 2-11%. For the roughly 75% of OHCAs that are unwitnessed, survival is approximately 2-4.4%, as there are no bystanders present to provide life-saving interventions and alert Emergency Medical Services. Sensor technologies may reduce the number of unwitnessed OHCAs through automated detection of OHCA-associated physiological changes. However, no technologies are widely available for OHCA detection. This review identifies research and commercial technologies developed for cardiopulmonary monitoring that may be best suited for use in the context of OHCA, and provides recommendations for technology development, testing, and implementation. We conducted a systematic review of published studies along with a search of grey literature to identify technologies that were able to provide cardiopulmonary monitoring, and could be used to detect OHCA. We searched MEDLINE, EMBASE, Web of Science, and Engineering Village using MeSH keywords. Following inclusion, we summarized trends and findings from included studies. Our searches retrieved 6945 unique publications between January, 1950 and May, 2023. 90 studies met the inclusion criteria. In addition, our grey literature search identified 26 commercial technologies. Among included technologies, 52% utilized electrocardiography (ECG) and 40% utilized photoplethysmography (PPG) sensors. Most wearable devices were multi-modal (59%), utilizing more than one sensor simultaneously. Most included devices were wearable technologies (84%), with chest patches (22%), wrist-worn devices (18%), and garments (14%) being the most prevalent. ECG and PPG sensors are heavily utilized in devices for cardiopulmonary monitoring that could be adapted to OHCA detection. Developers seeking to rapidly develop methods for OHCA detection should focus on using ECG- and/or PPG-based multimodal systems as these are most prevalent in existing devices. However, novel sensor technology development could overcome limitations in existing sensors and could serve as potential additions to or replacements for ECG- and PPG-based devices.

Unfavorable Neurological Outcomes with Incremental Cardiopulmonary Resuscitation Duration in Cardiac Arrest Brain Injury: A Systematic Review and Meta-Analysis

The duration of cardiopulmonary resuscitation (CPR) affects neurological outcomes. Conclusive data on its decremental effect on neurological outcomes have not been explored before in a quantitative review. PubMed and Google Scholar were searched for relevant studies from 2015 up to May 2023 using relevant keywords. The odds of good neurological outcomes were studied. Binary random effects were used to estimate pooled odds ratios (OR) and 95% confidence intervals (CI). A leave-one-out sensitivity analysis was performed. Heterogeneity was assessed using I 2 statistics. For outcomes showing moderate to high heterogeneity, subgroup analysis was performed for follow-up duration or type of study. A p value of < 0.05 was considered statistically significant. A total of 349,027 cardiac arrest patients (mean age, 70.2 years; males, 56.6%) from four studies were included in the meta-analysis. Of them, the initial rhythm was shockable in 11% (38,465/349,027) and non-shockable in 88.97% (310,562/349,027) of the population. Odds of having favorable neurological outcomes were 0.32 (95% CI 0.10–1.01, p = 0.05) for 6–10 min (n = 14,118), 0.10 (95% CI 0.02–0.64, p = 0.02) for 11–15 min (n = 43,885), 0.05 (95% CI 0.01–0.36, p 0.01) for 16–20 min (n = 66,174), 0.04 (95% CI 0.01–0.21, p < 0.01) for > 20 min (n = 181,262), and 0.03 (95% CI 0.00–1.55, p = 0.08) for > 30 min (n = 66,461) when compared to patients receiving CPR for < 5 min (n = 6420). Steady decremental odds of favorable neurological outcomes were seen with every 5 min of increased CPR duration, with a statistically significant decline seen in CPR duration from 11 to 15 min onwards.

Automated external defibrillator location and socioeconomic deprivation in Great Britain

OBJECTIVE

The early use of automated external defibrillators (AEDs) improves outcomes in out-of-hospital cardiac arrest (OHCA). We investigated AED access across Great Britain (GB) according to socioeconomic deprivation.

METHODS

Cross-sectional observational study using AED location data from The Circuit: the national defibrillator network led by the British Heart Foundation in partnership with the Association of Ambulance Chief Executives, Resuscitation Council UK and St John Ambulance. We calculated street network distances between all 1 677 466 postcodes in GB and the nearest AED and used a multilevel linear mixed regression model to investigate associations between the distances from each postcode to the nearest AED and Index of Multiple Deprivation, stratified by country and according to 24 hours 7 days a week (24/7) access.

RESULTS

78 425 AED locations were included. Across GB, the median distance from the centre of a postcode to an AED was 726 m (England: 739 m, Scotland: 743 m, Wales: 512 m). For 24/7 access AEDs, the median distances were further (991 m, 994 m, 570 m). In Wales, the average distance to the nearest AED and 24/7 AED was shorter for the most deprived communities. In England, the average distance to the nearest AED was also shorter in the most deprived areas. There was no association between deprivation and average distance to the nearest AED in Scotland. However, the distance to the nearest 24/7 AED was greater with increased deprivation in England and Scotland. On average, a 24/7 AED was in England and Scotland, respectively, 99.2 m and 317.1 m further away in the most deprived than least deprived communities.

CONCLUSION

In England and Scotland, there are differences in distances to the nearest 24/7 accessible AED between the most and least deprived communities. Equitable access to 'out-of-hours' accessible AEDs may improve outcomes for people with OHCA.

Cumulative dose of epinephrine and mode of death after non-shockable out-of-hospital cardiac arrest: a registry-based study

BACKGROUND

Epinephrine increases the chances of return of spontaneous circulation (ROSC) in out-of-hospital cardiac arrest (OHCA), especially when the initial rhythm is non-shockable. However, this drug could also worsen the post-resuscitation syndrome (PRS). We assessed the association between epinephrine use during cardiopulmonary resuscitation (CPR) and subsequent intensive care unit (ICU) mortality in patients with ROSC after non-shockable OHCA.

METHODS

We used data prospectively collected in the Sudden Death Expertise Center (SDEC) registry (capturing OHCA data located in the Greater Paris area, France) between May 2011 and December 2021. All adults with ROSC after medical, cardiac and non-cardiac causes, non-shockable OHCA admitted to an ICU were included. The mode of death in the ICU was categorized as cardiocirculatory, neurological, or other.

RESULTS

Of the 2,792 patients analyzed, there were 242 (8.7%) survivors at hospital discharge, 1,004 (35.9%) deaths from cardiocirculatory causes, 1,233 (44.2%) deaths from neurological causes, and 313 (11.2%) deaths from other etiologies. The cardiocirculatory death group received more epinephrine (4.6 ± 3.8 mg versus 1.7 ± 2.8 mg, 3.2 ± 2.6 mg, and 3.5 ± 3.6 mg for survivors, neurological deaths, and other deaths, respectively; p < 0.001). The proportion of cardiocirculatory death increased linearly (R2 = 0.92, p < 0.001) with cumulative epinephrine doses during CPR (17.7% in subjects who did not receive epinephrine and 62.5% in those who received > 10 mg). In multivariable analysis, a cumulative dose of epinephrine was strongly associated with cardiocirculatory death (adjusted odds ratio of 3.45, 95% CI [2.01-5.92] for 1 mg of epinephrine; 12.28, 95% CI [7.52-20.06] for 2-5 mg; and 23.71, 95% CI [11.02-50.97] for > 5 mg; reference 0 mg; population reference: alive at hospital discharge), even after adjustment on duration of resuscitation. The other modes of death (neurological and other causes) were also associated with epinephrine use, but to a lesser extent.

CONCLUSIONS

In non-shockable OHCA with ROSC, the dose of epinephrine used during CPR is strongly associated with early cardiocirculatory death. Further clinical studies aimed at limiting the dose of epinephrine during CPR seem warranted. Moreover, strategies for the prevention and management of PRS should take this dose of epinephrine into consideration for future trials.

Temporal trends in out-of-hospital cardiac arrest with an initial non-shockable rhythm in Singapore

Aim

Out-of-hospital cardiac arrest (OHCA) with an initial non-shockable rhythm is the predominant form of OHCA in adults. We evaluated its 10-year trends in epidemiology and management in Singapore.

Methods

Using the national OHCA registry we studied the trends of 20,844 Emergency Medical Services-attended adult OHCA from April 2010 to December 2019. Survival to hospital discharge was the primary outcome. Trends and outcomes were analyzed using linear and logistic regression, respectively.

Results

Incidence rates of adult OHCAs increased during the study period, driven by non-shockable OHCA. Compared to shockable OHCA, non-shockable OHCAs were significantly older, had more co-morbidities, unwitnessed and residential arrests, longer no-flow time, and received less bystander cardiopulmonary resuscitation (CPR) and in-hospital interventions (p < 0.001). Amongst non-shockable OHCA, age, co-morbidities, residential arrests, no-flow time, time to patient, bystander CPR and epinephrine administration increased during the study period, while presumed cardiac etiology decreased (p < 0.05). Unlike shockable OHCA, survival for non-shockable OHCA did not improve (p < 0.001 for trend difference). The likelihood of survival for non-shockable OHCA significantly increased with witnessed arrest (adjusted odds ratio (aOR) 2.02) and bystander CPR (aOR 3.25), but decreased with presumed cardiac etiology (aOR 0.65), epinephrine administration (aOR 0.66), time to patient (aOR 0.93) and age (aOR 0.98). Significant two-way interactions were observed for no-flow time and residential arrest with bystander CPR (aOR 0.96 and 0.40 respectively).

Conclusion

The incidence of non-shockable OHCA increased between 2010 and 2019. Despite increased interventions, survival did not improve for non-shockable OHCA, in contrast to the improved survival for shockable OHCA.

Pathophysiology and treatment of adults with arrhythmias in the emergency department, part 2: Ventricular and bradyarrhythmias

PURPOSE

This is the second article in a 2-part series reviewing the pathophysiology and treatment considerations for arrhythmias. Part 1 of the series discussed aspects related to treating atrial arrhythmias. Here in part 2, the pathophysiology of ventricular arrhythmias and bradyarrhythmias and current evidence on treatment approaches are reviewed.

SUMMARY

Ventricular arrhythmias can arise suddenly and are a common cause of sudden cardiac death. Several antiarrhythmics may be effective in management of ventricular arrhythmias, but there is robust evidence to support the use of only a few of these agents, and such evidence was largely derived from trials involving patients with out-of-hospital cardiac arrest. Bradyarrhythmias range from asymptomatic mild prolongation of nodal conduction to severe conduction delays and impending cardiac arrest. Vasopressors, chronotropes, and pacing strategies require careful attention and titration to minimize adverse effects and patient harm.

CONCLUSION

Ventricular arrhythmias and bradyarrhythmias can be consequential and require acute intervention. As experts in pharmacotherapy, acute care pharmacists can participate in providing high-level intervention by aiding in diagnostic workup and medication selection.

Prognosis of Cardiac Arrest-Peri-arrest and Post-arrest Considerations

There has been only a small improvement in survival and neurologic outcomes in patients with cardiac arrest in recent decades. Type of arrest, length of total arrest time, and location of arrest alter the trajectory of survival and neurologic outcome. In the post-arrest phase, clinical markers such as blood markers, pupillary light response, corneal reflex, myoclonic jerking, somatosensory evoked potential, and electroencephalography testing can be used to help guide neurological prognostication. Most of the testing should be performed 72 hours post-arrest with special considerations for longer observation periods in patients who underwent TTM or who had prolonged sedation and/or neuromuscular blockade.

Successful treatment of out-of-hospital cardiac arrest is still based on quick activation of the chain of survival

Background and goal of study

Cardiopulmonary resuscitation (CPR) in prehospital care is a major reason for emergency medical service (EMS) dispatches. CPR outcome depends on various factors, such as bystander CPR and initial heart rhythm. Our aim was to investigate whether short-term outcomes such as the return of spontaneous circulation (ROSC) and hospital admission with spontaneous circulation differ depending on the location of the out-of-hospital cardiac arrest (OHCA). In addition, we assessed further aspects of CPR performance.

Materials and methods

In this monocentric retrospective study, protocols of a prehospital physician-staffed EMS located in Munich, Germany, were evaluated using the Mann-Whitney U-test, chi-square test, and a multifactor logistic regression model.

Results and discussion

Of the 12,073 cases between 1 January 2014 and 31 December 2017, 723 EMS responses with OHCA were analyzed. In 393 of these cases, CPR was performed. The incidence of ROSC did not differ between public and non-public spaces (p = 0.4), but patients with OHCA in public spaces were more often admitted to the hospital with spontaneous circulation (p = 0.011). Shockable initial rhythm was not different between locations (p = 0.2), but defibrillation was performed significantly more often in public places (p < 0.001). Multivariate analyses showed that hospital admission with spontaneous circulation was more likely in patients with shockable initial heart rhythm (p < 0.001) and if CPR was started by an emergency physician (p = 0.006).

Conclusion

The location of OHCA did not seem to affect the incidence of ROSC, although patients in public spaces had a higher chance to be admitted to the hospital with spontaneous circulation. Shockable initial heart rhythm, defibrillation, and the start of resuscitative efforts by an emergency physician were associated with higher chances of hospital admission with spontaneous circulation. Bystander CPR and bystander use of automated external defibrillators were low overall, emphasizing the importance of bystander education and training in order to enhance the chain of survival.

In-hospital cardiac arrest rhythm analysis by anesthesiologists: a diagnostic performance study

PURPOSE

In-hospital cardiac arrest is associated with high morbidity and mortality, with an overall survival rate at one year of approximately 13%. The first cardiac rhythm is often analyzed by anesthesiologist-intensivists. We aimed to determine the diagnostic performance of anesthesiologist-intensivists when distinguishing between shockable and nonshockable rhythms.

METHODS

We conducted a simulation-based, multicentre, prospective, observational study between May 2019 and March 2020. The responses of the participants were used to calculate individual sensitivity (defined as the proportion of decisions to shock for shockable rhythms) and individual specificity (defined as the proportion of decisions not to shock for nonshockable rhythms). The main outcome measure was the overall diagnostic performance, defined as the overall sensitivity and specificity. Secondary outcome measures were the sensitivity and specificity of participants' decisions for each type of cardiac arrest rhythm and their decision-making times.

RESULTS

Among the 267 physicians contacted, 179 (67%) completed the test. The median [interquartile range (IQR)] overall sensitivity was 88 [79-95]% and the median overall specificity was 86 [77-92]%. Among shockable rhythms, the median [IQR] sensitivity was 100 [100-100]% for ventricular tachycardia (VT), 100 [100-100]% for coarse ventricular fibrillation (VF), and 60 [20-100]% for fine VF. The median [IQR] specificities for nonshockable rhythms were 93 [86-100]% for asystole and 83 [72-86]% for pulseless electrical activity. The median decision times ranged from 2.0 to 3.5 sec.

CONCLUSION

Anesthesiologist-intensivists were quickly and effectively able to analyze rhythms in this simulation-based study. Participants' sensitivity in deciding to deliver shocks for VT and coarse VF was excellent, while specificity of their decisions for pulseless electrical activity was insufficient.

The Impact of Prehospital and Hospital Care on Clinical Outcomes in Out-of-Hospital Cardiac Arrest

Background: In recent years, several actions have been made to shorten the chain of survival in out-of-hospital cardiac arrest (OHCA). These include placing defibrillators in public places, training first responders, and providing dispatcher-assisted CPR (DA-CPR). In this work, we aimed to evaluate the impact of these changes on patients' outcomes, including achieving return of spontaneous circulation (ROSC), survival to discharge, and survival with favorable neurological function. Methods: We retrospectively retrieved data of all calls to the national emergency medical service in Ashdod city, Israel, of individuals who underwent OHCA at the age of 18 and older between the years 2018 and 2021. Data was collected on prehospital and hospital interventions. The association between pre-hospital and hospital interventions to ROSC, survival to discharge, and neurological outcomes was evaluated. Logistic regression was used for multivariable analysis. Results: During the years 2018-2021, there were 1253 OHCA cases in the city of Ashdod. ROSC was achieved in 207 cases (32%), survival to discharge was attained in 48 cases (7.4%), and survival with favorable neurological function was obtained in 26 cases (4%). Factors significantly associated with good prognosis were shockable rhythm, witnessed arrest, DA-CPR, use of AED, and treatment for STEMI. All patients that failed to achieve ROSC outside of the hospital setting had a poor prognosis. Conclusions: This study demonstrates the prognostic role of the initial rhythm and the use of AED in OHCA. Hospital management, including STEMI documentation and catheterization, was also an important prognostication factors. Additionally, when ROSC is not achieved in the field, hospital transfer should be considered.

Eligibility of out-of-hospital cardiac arrest patients for extracorporeal cardiopulmonary resuscitation in the United States: A geographic information system model

BACKGROUND

Recent evidence suggest that extracorporeal cardiopulmonary resuscitation (ECPR) may improve survival rates for nontraumatic out-of-hospital cardiac arrest (OHCA). Eligibility criteria for ECPR are often based on patient age, clinical variables, and facility capabilities. Expanding access to ECPR across the U.S. requires a better understanding of how these factors interact with transport time to ECPR centers.

METHODS

We constructed a Geographic Information System (GIS) model to estimate the number of ECPR candidates in the U.S. We utilized a Resuscitation Outcome Consortium (ROC) database to model time-dependent rates of ECPR eligibility and the Cardiac Arrest Registry to Enhance Survival (CARES) registry to determine the total number of OHCA patients who meet pre-specified ECPR criteria within designated transportation times. The combined model was used to estimate the total number of ECPR candidates.

RESULTS

There were 588,203 OHCA patients in the CARES registry from 2013 to 2020. After applying clinical eligibility criteria, 22,104 (3.76%) OHCA patients were deemed eligible for ECPR. The rate of ROSC increased with longer resuscitation time, which resulted in fewer ECPR candidates. The proportion of OHCA patients eligible for ECPR increased with older age cutoffs. Only 1.68% (9,889/588,203) of OHCA patients in the U.S. were eligible for ECPR based on a 45-minute transportation time to an ECMO-ready center model.

CONCLUSIONS

Less than 2% of OHCA patients are eligible for ECPR in the U.S. GIS models can identify the impact of clinical criteria, transportation time, and hospital capabilities on ECPR eligibility to inform future implementation strategies.

[AED drones on the rise? : Use of drones to improve public access defibrillation]

BACKGROUND

The poor availability of automatic external defibrillators (AED) and the modest knowledge of lay persons in handling these devices has led to an insufficient spread of public access defibrillation in Germany.

OBJECTIVE

This article examines whether the automated deployment of AED drones to out-of-hospital cardiac arrest can help to remedy this situation.

METHODS

Narrative literature review, evaluation of statistics, analysis of relevant media reports, and discussion of key research.

RESULTS

The present investigations are mainly located in the experimental field and demonstrate the feasibility and safety of drone use, as well as shorter times to first defibrillation, which is confirmed by initial clinical studies. Mathematical models also indicate cost-effectiveness of airborne AED delivery compared to ground dispatch. Integration into the chain of survival appears to be possible but adaptations to existing emergency medical service structures and close cooperation with regional first responder and AED schemes as well as local authorities is required to optimise patient benefit and efficiency.

CONCLUSION

The use of AED drones could probably contribute to improving public access defibrillation in Germany. This applies to both rural and urban regions. The technological requirements are met but flight regulations still have to be amended. In order to explore the full potential of this novel technology, further field trials are required to achieve smooth integration into existing emergency medical services.

Firefighters as first-responders in out-of-hospital cardiac arrest- a retrospective study of a time-gain selective dispatch system in the Skåne Region, Sweden

AIM

To analyze the impact of a time-gain selective, first-responder dispatch system on the presence of a shockable initial rhythm (SIR), return of spontaneous circulation (ROSC) and 30-day survival after out-of-hospital cardiac arrest (OHCA).

METHOD

A retrospective observational study comprising OHCA registry data and dispatch data in the Skåne Region, Sweden (2010-2018). Data were categorized according to dispatch procedures, two ambulances (AMB-only) versus two ambulances and firefighter first-responders (DUAL-dispatch), based on the dispatcher's estimation of a time-gain. Dual dispatch was sub-categorized by arrival of first vehicle (first-responder or ambulance). Logistic regressions were used, additionally with groups matched (1:1) for age, witnessed event, bystander cardiopulmonary resuscitation and ambulance response time. Adjusted and conditional odds-ratios (aOR, cOR) with 95% confidence intervals (CI) are presented.

RESULTS

Of 3,245 eligible cases, 43% were DUAL-dispatches with first-responders first on scene (FR-first) in 72%. Despite a five-minute median reduction in response time in the FR-first group, no association with SIR was found (aOR 0.83, 95%CI 0.64-1.07) nor improved 30-day survival (aOR 1.03, 95%CI 0.72-1.47). A positive association between ROSC and the FR-first group (aOR 1.25, 95%CI 1.02-1.54) disappeared in the matched analysis (cOR 1.12, 95%CI 0.87-1.43). Time to first monitored rhythm was 7:06 minutes in the FR-first group versus 3:01 in the combined AMB-only/AMB-first groups.

CONCLUSION

In this time-gain selective first-responder dispatch system, a shorter response time was not associated with increased SIR, improved ROSC rate or survival. Process measures differed between the study groups which could account for the observed findings and requires further investigation.

Out-of-hospital cardiac arrest in the Algarve region of Portugal: a retrospective registry trial with outcome data

BACKGROUND AND IMPORTANCE

Out-of-hospital cardiac arrest is a leading cause of death in Europe. An understanding of region-specific factors is essential for informing strategies to improve survival.

DESIGN

This retrospective observational study included all out-of-hospital cardiac arrest patients attended by the Emergency Medical Service of the Algarve in 2019. Outcome data were derived from hospital records.

MAIN RESULTS

In 2019, there were 850 out-of-hospital cardiac arrests treated with cardiopulmonary resuscitation in the Algarve, representing a population incidence of 189/100 000. Return of spontaneous circulation occurred in 83 patients (9.8%), of whom 17 (2.0%) had survival to hospital discharge and 15 (1.8%) had survival with good neurologic outcome. Among patients in the Utstein comparator group, survival to hospital discharge was 21.4%. Predictors of return of spontaneous circulation were age, witnessed arrest, initial shockable rhythm, time of year, time to cardiopulmonary resuscitation, and time to advanced life support. Predictors of survival to hospital discharge were age, initial shockable rhythm, time to rhythm analysis, and time to advanced life support. Predictors of survival with good neurologic outcome were age, initial shockable rhythm, and time to return of spontaneous circulation.

CONCLUSIONS

The incidence of out-of-hospital cardiac arrest with cardiopulmonary resuscitation in the Algarve was higher than in other jurisdictions while return of spontaneous circulation, survival to hospital discharge, and survival with good neurologic outcome were comparatively low. An aging population, a geographically diverse region, and a low incidence of bystander cardiopulmonary resuscitation may have contributed to these outcomes. These results confirm the importance of early cardiopulmonary resuscitation, early rhythm assessment, and early advanced life support, all of which are potentially modifiable through public education, broadening of the defibrillator network and increased availability of advanced life support teams.

Trends in out-of-hospital cardiac arrest incidence, patient characteristics and survival over 18 years in Perth, Western Australia

Objectives

To investigate trends in the incidence, characteristics, and survival of out-of-hospital cardiac arrests (OHCA) in the Perth metropolitan area between 2001 and 2018.

Methods

We calculated the crude incidence rate, age-standardised incidence rate (ASIR) and age- and sex-specific incidence rates (per 100,000 population) for OHCA of presumed cardiac aetiology. ASIRs were calculated using the direct method of standardisation using the 2001 Australian Population standard. Survival was assessed at return of spontaneous circulation at emergency department arrival and at 30 days. Temporal trends in patient and arrest characteristics were assessed with logistic regression, while trends in incidence were assessed using Joinpoint regression. Survival trends were assessed using binary logistic regression.

Results

A total of 18,417 OHCAs of presumed cardiac aetiology were attended by emergency medical services in Perth between 2001 and 2018. Overall, there were no significant changes in the crude or ASIR of OHCA over the study period, although OHCA incidence in 15–39 year-old males increased by 12.5% annually between 2011 and 2018. Both bystander cardiopulmonary resuscitation and bystander defibrillation increased over the study period, while the proportion of shockable arrests declined. Thirty-day OHCA survival improved significantly over time, with the odds of survival (in bystander-witnessed, initial shockable rhythm arrests) improving 12% (95% CI, 9.0% to 14.0%) annually, from 8.4% in 2001 to 44.0% in 2018.

Conclusion

Overall, there were no significant trends in OHCA incidence over the study period, although arrests in 15–39 year-old males increased significantly after 2011. There were significant improvements in 30-day survival between 2001 and 2018.

Using QRS loop descriptors to characterize the risk of sudden cardiac death in patients with structurally normal hearts

The predictive value of non-invasive electrocardiographic examination findings for the risk of sudden cardiac death (SCD) in populations with structurally normal hearts remains unclear. This study aimed to investigate the characteristics of the QRS vectorcardiography of surface electrocardiography in patients with structurally normal hearts who experienced SCD. We consecutively enrolled patients who underwent vectorcardiography between March 2017 and December 2018 in a tertiary referral medical center. These patients didn’t have structural heart diseases, histories of congestive heart failure, or reduced ejection fraction, and they were classified into SCD (with aborted SCD history and cerebral performance category score of 1) and control groups (with an intervention for atrioventricular node reentrant tachycardia and without SCD history). A total of 162 patients (mean age, 54.3±18.1 years; men, 75.9%), including 59 in the SCD group and 103 in the control group, underwent propensity analysis. The baseline demographic variables, underlying diseases, QRS loop descriptors (the percentage of the loop area, loop dispersion, and inter-lead QRS dispersion), and other electrocardiographic parameters were compared between the two groups. In the univariate and multivariate analyses, a smaller percentage of the loop area (odds ratio, 0.0003; 95% confidence interval, 0.00–0.02; p<0.001), more significant V4-5 dispersion (odds ratio, 1.04; 95% confidence interval, 1.02–1.07; p = 0.002), and longer QRS duration (odds ratio, 1.05; 95% confidence interval, 1.00–1.10; p = 0.04) were associated with SCD. In conclusion, the QRS loop descriptors of surface electrocardiography could be used as non-invasive markers to identify patients experiencing aborted SCD from a healthy population. A decreased percentage of loop area and elevated V4-5 QRS dispersion values assessed using vectorcardiography were associated with an increased risk of SCD in patients with structurally normal hearts.

Epidemiology and risk factors of sudden cardiac arrest

PURPOSE OF REVIEW

Sudden cardiac arrest (SCA) remains a major health burden around the globe, most often occurring in the community (out-of-hospital cardiac arrest [OHCA]). SCA accounts for 15-20% of all natural deaths in adults in the USA and Western Europe, and up to 50% of all cardiovascular deaths. To reduce this burden, more knowledge is needed about its key facets such as its incidence in various geographies, its risk factors, and the populations that may be at risk.

RECENT FINDINGS

SCA results from a complex interaction of inherited and acquired causes, specific to each individual. Resolving this complexity, and designing personalized prevention and treatment, requires an integrated approach in which big datasets that contain all relevant factors are collected, and a multimodal analysis. Such datasets derive from multiple data sources, including all players in the chain-of-care for OHCA. This recognition has led to recently started large-scale collaborative efforts in Europe.

SUMMARY

Our insights into the causes of SCA are steadily increasing thanks to the creation of big datasets dedicated to SCA research. These insights may be used to earlier recognize of individuals at risk, the design of personalized methods for prevention, and more effective resuscitation strategies for OHCA.

The Comparison of Emergency Medical Service Responses to and Outcomes of Out-of-hospital Cardiac Arrest before and during the COVID-19 Pandemic in an Area of Korea

BACKGROUND

Since the declaration of the coronavirus disease 2019 (COVID-19) pandemic, COVID-19 has affected the responses of emergency medical service (EMS) systems to cases of out-of-hospital cardiac arrest (OHCA). The purpose of this study was to identify the impact of the COVID-19 pandemic on EMS responses to and outcomes of adult OHCA in an area of South Korea.

METHODS

This was a retrospective observational study of adult OHCA patients attended by EMS providers comparing the EMS responses to and outcomes of adult OHCA during the COVID-19 pandemic to those during the pre-COVID-19 period. Propensity score matching was used to compare the survival rates, and logistic regression analysis was used to assess the impact of the COVID-19 pandemic on the survival of OHCA patients.

RESULTS

A total of 891 patients in the pre-COVID-19 group and 1,063 patients in the COVID-19 group were included in the final analysis. During the COVID-19 period, the EMS call time was shifted to a later time period (16:00-24:00, P < 0.001), and the presence of an initial shockable rhythm was increased (pre-COVID-19 vs. COVID-19, 7.97% vs. 11.95%, P = 0.004). The number of tracheal intubations decreased (5.27% vs. 1.22%, P < 0.001), and the use of mechanical chest compression devices (30.53% vs. 44.59%, P < 0.001) and EMS response time (median [quartile 1-quartile 3], 7 [5-10] vs. 8 [6-11], P < 0.001) increased. After propensity score matching, the survival at admission rate (22.52% vs. 18.24%, P = 0.025), survival to discharge rate (7.77% vs. 5.52%, P = 0.056), and favorable neurological outcome (5.97% vs. 3.49%, P < 0.001) decreased. In the propensity score matching analysis of the impact of COVID-19, odds ratios of 0.768 (95% confidence interval [CI], 0.592-0.995) for survival at admission and 0.693 (95% CI, 0.446-1.077) for survival to discharge were found.

CONCLUSION

During the COVID-19 period, there were significant changes in the EMS responses to OHCA. These changes are considered to be partly due to social distancing measures. As a result, the proportion of patients with an initial shockable rhythm in the COVID-19 period was greater than that in the pre-COVID-19 period, but the final survival rate and favorable neurological outcome were lower.

Out-of-hospital cardiac arrest and differential risk of cardiac and non-cardiac QT-prolonging drugs in 37 000 cases

Aims

Drugs that prolong the QT interval, either by design (cardiac QT‐prolonging drugs: anti‐arrhythmics) or as off‐target effect (non‐cardiac QT‐prolonging drugs), may increase the risk of ventricular arrhythmias and out‐of‐hospital cardiac arrest (OHCA). Risk mitigation measures were instituted, in particular, surrounding prescription of cardiac QT‐prolonging drugs. We studied OHCA risk of both drug types in current clinical practice.

Methods

Using data from large population‐based OHCA registries in the Netherlands and Denmark, we conducted two independent case–control studies. OHCA cases with presumed cardiac causes were matched on age/sex/index date with up to five non‐OHCA controls. We calculated odds ratios (ORs) for the association of cardiac or non‐cardiac QT‐prolonging drugs with OHCA risk using conditional logistic regression analyses.

Results

We identified 2503 OHCA cases and 10 543 non‐OHCA controls in the Netherlands, and 35 017 OHCA cases and 175 085 non‐OHCA controls in Denmark. Compared to no use of QT‐prolonging drugs, use of non‐cardiac QT‐prolonging drugs (Netherlands: cases: 3.0%, controls: 1.9%; Denmark: cases: 14.9%, controls: 7.5%) was associated with increased OHCA risk (Netherlands: OR 1.37 [95% CI: 1.03–1.81]; Denmark: OR 1.63 [95% CI: 1.57–1.70]). The association between cardiac QT‐prolonging drugs (Netherlands: cases: 4.0%, controls: 2.5%; Denmark: cases: 2.1%, controls: 0.9%) and OHCA was weaker (Netherlands: OR 1.17 [95% CI: 0.92–1.50]; Denmark: OR 1.21 [95% CI: 1.09–1.33]), although users of cardiac QT‐prolonging drugs had more medication use and comorbidities associated with OHCA risk than users of non‐cardiac QT‐prolonging drugs.

Conclusion

In clinical practice, cardiac QT‐prolonging drugs confer lower OHCA risk than non‐cardiac QT‐prolonging drugs, although users of the former have higher a priori risk. This is likely due to risk mitigation measures surrounding prescription of cardiac QT‐prolonging drugs.

A Machine Learning Model for the Prognosis of Pulseless Electrical Activity during Out-of-Hospital Cardiac Arrest

Pulseless electrical activity (PEA) is characterized by the disassociation of the mechanical and electrical activity of the heart and appears as the initial rhythm in 20–30% of out-of-hospital cardiac arrest (OHCA) cases. Predicting whether a patient in PEA will convert to return of spontaneous circulation (ROSC) is important because different therapeutic strategies are needed depending on the type of PEA. The aim of this study was to develop a machine learning model to differentiate PEA with unfavorable (unPEA) and favorable (faPEA) evolution to ROSC. An OHCA dataset of 1921 5s PEA signal segments from defibrillator files was used, 703 faPEA segments from 107 patients with ROSC and 1218 unPEA segments from 153 patients with no ROSC. The solution consisted of a signal-processing stage of the ECG and the thoracic impedance (TI) and the extraction of the TI circulation component (ICC), which is associated with ventricular wall movement. Then, a set of 17 features was obtained from the ECG and ICC signals, and a random forest classifier was used to differentiate faPEA from unPEA. All models were trained and tested using patientwise and stratified 10-fold cross-validation partitions. The best model showed a median (interquartile range) area under the curve (AUC) of 85.7(9.8)% and a balance accuracy of 78.8(9.8)%, improving the previously available solutions at more than four points in the AUC and three points in balanced accuracy. It was demonstrated that the evolution of PEA can be predicted using the ECG and TI signals, opening the possibility of targeted PEA treatment in OHCA.

European first responder systems and differences in return of spontaneous circulation and survival after out-of-hospital cardiac arrest: A study of registry cohorts

BACKGROUND

In Europe, survival-rates after out-of-hospital cardiac arrest (OHCA) vary widely between regions. Whether a system dispatching First Responders (FRs; main FR-types: firefighters, police officers, citizen-responders) is present or not may be associated with survival-rates. This study aimed to assess the association between having a dispatched FR-system and rates of return of spontaneous circulation (ROSC) and survival across Europe.

METHODS

Results of an inventory of dispatched FR-systems for OHCA in Europe were combined with aggregate ROSC and survival data from the EuReCa-TWO study and additionally collected data. Regression analysis (weighted on number of patients included per region) was performed to study the association between having a dispatched FR-system and ROSC and survival-rates to hospital discharge in the total population and in patients with shockable initial rhythm, witnessed OHCA and bystander cardiopulmonary resuscitation (CPR; Utstein comparator group). For regions without a dispatched FR-system, the theoretical survival-rate if a dispatched FR-system would have existed was estimated.

FINDINGS

We included 27 European regions. There were 15,859 OHCAs in the total group and 2,326 OHCAs in the Utstein comparator group. Aggregate ROSC and survival-rates were significantly higher in regions with an FR-system compared to regions without (ROSC: 36% [95%CI 35%-37%] vs. 24% [95%CI 23%-25%]; P<0.001; survival in total population [N=15.859]: 13% [95%CI 12%-15%] vs. 5% [95%CI 4%-6%]; P<0.001; survival in Utstein comparator group [N=2326]: 33% [95%CI 30%-36%] vs. 18% [95%CI 16%-20%]; P<0.001), and in regions with more than one FR-type compared to regions with only one FR-type. All main FR-types were associated with higher survival-rates (all P<0.050).

INTERPRETATION

European regions with dispatched FRs showed higher ROSC and survival-rates than regions without.

FUNDING

This project/work has received funding from the European Union's Horizon 2020 research and innovation programme under acronym ESCAPE-NET, registered under grant agreement No 733381 (IO, HLT and MTB) and the European Union's COST programme under acronym PARQ, registered under grant agreement No CA19137 (IO, DC, HLT, MTB). HLT and MTB were supported by a grant from the Netherlands CardioVascular Research Initiative, Dutch Heart Foundation, Dutch Federation of University Medical Centres, Netherlands Organization for Health Research and Development, Royal Netherlands Academy of Sciences - CVON2017-15 RESCUED (HLT), and CVON2018-30 Predict2 (HLT and MTB).