Modifiable Factors Associated With Survival After Out-of-Hospital Cardiac Arrest in the Pan-Asian Resuscitation Outcomes Study

The role of bystander CPR in out-of-hospital cardiac arrest: what the evidence tells us

Out-of-hospital cardiac arrest (OHCA) is a global public health problem. Lay bystanders witness almost half of OHCA, so early recognition is critical to allow immediate initiation of cardiopulmonary resuscitation (CPR) by the bystander. The present investigation aims to analyze the most recent scientific evidence of the effect of bystander CPR on survival after an OHCA. A systematic literature review was carried out at the "Web of Science," "Scopus," and "PubMed" databases, including publications from the last 20 years. After inclusion/exclusion criteria, 37 articles were identified. Results indicate that patients who receive CPR are more likely to survive than those who don't, and CPR is associated with a good quality of life post-OHCA. Emphasis should be placed on practicing chest compressions only when the bystander has not mastered the artificial ventilation technique. Finding an AED is the first step to using it in an OHCA situation. Correct use of an AED by laypeople is associated with nearly double the survival rate after an OHCA when compared to standard CPR. It is important to promote CPR and AED training to non-professionals, such as community residents and youth, as training is associated with higher success rates of effective CPR-AED. A mobile phone positioning system to recruit trained laypeople or text message alerts to send citizen volunteers as well as assistance through a mobile app appear to have significant advantages in practicing effective CPR. The benefits of bystander CPR outweigh the risk of injury to victims, highlighting the need to disseminate training to laypeople.

Emergent Management of Hypoxic-Ischemic Brain Injury

OBJECTIVE

This article outlines interventions used to improve outcomes for patients with hypoxic-ischemic brain injury after cardiac arrest.

LATEST DEVELOPMENTS

Emergent management of patients after cardiac arrest requires prevention and treatment of primary and secondary brain injury. Primary brain injury is minimized by excellent initial resuscitative efforts. Secondary brain injury prevention requires the detection and correction of many pathophysiologic processes that may develop in the hours to days after the initial arrest. Key physiologic parameters important to secondary brain injury prevention include optimization of mean arterial pressure, cerebral perfusion, oxygenation and ventilation, intracranial pressure, temperature, and cortical hyperexcitability. This article outlines recent data regarding the treatment and prevention of secondary brain injury. Different patients likely benefit from different treatment strategies, so an individualized approach to treatment and prevention of secondary brain injury is advisable. Clinicians must use multimodal sources of data to prognosticate outcomes after cardiac arrest while recognizing that all prognostic tools have shortcomings.

ESSENTIAL POINTS

Neurologists should be involved in the postarrest care of patients with hypoxic-ischemic brain injury to improve their outcomes. Postarrest care requires nuanced and patient-centered approaches to the prevention and treatment of primary and secondary brain injury and neuroprognostication.

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

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

Wolf creek XVII part 4: Amplifying lay-rescuer response

Introduction

Amplifying lay-rescuer response is a key priority to increase survival from out-of-hospital cardiac arrest (OHCA). We describe the current state of lay-rescuer response, how we envision the future, and the gaps, barriers, and research priorities that will amplify response to OHCA.

Methods

'Amplifying Lay-Rescuer Response' was one of six focus topics for the Wolf Creek XVII Conference held on June 14-17, 2023, in Ann Arbor, Michigan, USA. Conference invitees included international thought leaders and scientists in the field of cardiac arrest resuscitation from academia and industry. Participants submitted via online survey knowledge gaps, barriers to translation and research priorities for each focus topic. Expert panels used the survey results and their own perspectives and insights to create and present a preliminary unranked list for each category that was debated, revised and ranked by all attendees to identify the top 5 for each category.

Results

The top five knowledge gaps as ranked by the panel, reflected a recognition of the need to better understand the psycho-social aspects of lay response. The top five barriers to translation reflected issues at the individual, community, societal, structural, and governmental levels. The top five research priorities were focused on understanding the social/psychological and emotional barriers to action, finding the most effective/cost-effective strategies to educate lay persons and implement community life-saving interventions, evaluation of new technological solutions and how to enhance the role of dispatch working with lay-rescuers.

Conclusion

Future research in lay rescuer response should incorporate technology innovations, understand the "humanity" of the situation, leverage implementation science and systems thinking to save lives. This will require the field of resuscitation to engage with scholars outside our traditional ranks and to be open to new ways of thinking about old problems.

Lower versus higher oxygen targets after resuscitation from out-of-hospital cardiac arrest: A systematic review and meta-analysis of randomized controlled trials

PURPOSE

To update the existing evidence and gain further insight into effects of lower versus higher oxygen targets on the outcomes in patients resuscitated from out-of-hospital cardiac arrest (OHCA).

METHODS

We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing lower versus higher oxygen targets on the outcomes among adults resuscitated from OHCA. The primary outcome was short-term survival (in hospital or within 30 days). Subgroup analyses were performed according to timing of study interventions.

RESULTS

Seven RCTs with 1454 patients were finally included. The short-term survival did not differ between the two groups with a relative risk (RR) of 0.98 (95% CI, 0.86 to 1.11). There were no significant differences in survival at longest follow-up (RR, 1.01; 95% CI, 0.91 to 1.14), favorable neurological outcome (RR, 1.00; 95% CI, 0.91 to 1.11), length of intensive care unit stay (mean difference, -4.94 h; 95% CI, -14.83 to 4.96 h), or risk of re-arrest (RR, 0.68; 95% CI, 0.21 to 2.19). The quality of evidence ranged from moderate to very low.

CONCLUSION

Current evidence suggests that targeting a lower or higher oxygen therapy in patients after resuscitation from OHCA results in similar short-term survival and other clinical outcomes.

Prehospital factors associated with out-of-hospital cardiac arrest outcomes in a metropolitan city: a 4-year multicenter study

BACKGROUND

Prehospital factors play a vital role in out-of-hospital cardiac arrest (OHCA) survivability, and they vary between countries and regions. We investigated the prehospital factors associated with OHCA outcomes in a single metropolitan city in the Republic of Korea.

METHODS

This study included adult medical OHCA patients enrolled prospectively, using data from the citywide OHCA registry for patients registered between 2018 and 2021. The primary outcome was survival to hospital discharge. Multivariable logistic regression analysis was conducted to determine the factors associated with the study population's clinical outcomes, adjusting for covariates. We performed a sensitivity analysis for clinical outcomes only for patients without prehospital return of spontaneous circulation prior to emergency medical service departure from the scene.

RESULTS

In multivariable logistic regression analysis, older age (odds ratio [OR] 0.96; 95% confidence interval [CI] 0.95-0.97), endotracheal intubation (adjusted odds ratio [aOR] 0.29; 95% [CIs] 0.17-0.51), supraglottic airway (aOR 0.29; 95% CI 0.17-0.51), prehospital mechanical chest compression device use (OR 0.13; 95% CI 0.08-0.18), and longer scene time interval (OR 0.96; 95% CI 0.93-1.00) were negatively associated with survival. Shockable rhythm (OR 24.54; 95% CI 12.99-42.00), pulseless electrical activity (OR 3.11; 95% CI 1.74-5.67), and witnessed cardiac arrest (OR 1.59; 95% CI 1.07-2.38) were positively associated with survival. In the sensitivity analysis, endotracheal intubation, supraglottic airway, prehospital mechanical chest compression device use, and longer scene time intervals were associated with significantly lower survival to hospital discharge.

CONCLUSIONS

Regional resuscitation protocol should be revised based on the results of this study, and modifiable prehospital factors associated with lower survival of OHCA should be improved.

Impact of time-to-compression on out-of-hospital cardiac arrest survival outcomes: A national registry study

OBJECTIVE

We aimed to quantify the association of no-flow interval in out-of-hospital cardiac arrests (OHCA) with the odds of neurologically favorable survival and survival to hospital discharge/ 30th day. Our secondary aim was to explore futility thresholds to guide clinical decisions, such as prehospital termination of resuscitation.

METHODS

All OHCAs from 2012 to 2017 in Singapore were extracted. We examined the association between no-flow interval (continuous variable) and survival outcomes using univariate and multivariable logistic regressions. The primary outcome was survival with favorable cerebral performance (Glasgow-Pittsburgh Cerebral Performance Categories 1/2), the secondary outcome was survival to hospital discharge/ 30th day if not discharged. To determine futility thresholds, we plotted the adjusted probability of good neurological outcomes to no-flow interval.

RESULTS

12,771 OHCAs were analyzed. The per-minute adjusted OR when no-flow interval was incorporated as a continuous variable in the multivariable model was: good neurological function- aOR 0.98 (95%CI: 0.97-0.98); survival to discharge- aOR 0.98 (95%CI: 0.98-0.99). Taking the 1% futility of survival line gave a no-flow interval cutoff of 12 mins (NPV 99%, sensitivity 85% and specificity 42%) overall and 7.5 mins for witnessed arrests.

CONCLUSION

We demonstrated that prolonged no-flow interval had a significant effect on lower odds of favorable neurological outcomes, with medical futility occurring when no-flow interval was >12 mins (>7.5 mins for witnessed arrest). Our study adds to the literature of the importance of early CPR and EMS response and provided a threshold beyond traditional 'down-times', which could aid clinical decisions in TOR or OHCA management.

Out-of-hospital cardiac arrest: A data-driven visualization of collaboration, frontier identification, and future trends

One of the main causes of death is out-of-hospital cardiac arrest (OHCA), which has a poor prognosis and poor neurological outcomes. This phenomenon has attracted increasing attention. However, there is still no published bibliometric analysis of OHCA. This bibliometric analysis of publications on OHCA aimed to visualize the current status of research, determine the frontiers of research, and identify future trends. Publications on OHCA were downloaded from the web of science database. The data elements included year, countries/territories, institutions, authors, journals, research areas, citations of publications, etc. Joinpoint regression and exponential models were used to identify and predict the trend of publications, respectively. Knowledge domain maps were applied to conduct contribution and collaboration, cooccurrence, cocitation, and coupled analyses. Timeline and burst detection analysis were used to identify the frontiers in the field. A total of 3 219 publications on OHCA were found from 1998 to 2022 (average annual percentage change = 16.7; 95% CI 14.4, 19.1). It was estimated that 859 articles and reviews would be published in 2025. The following research hotpots were identified: statement, epidemiology, clinical care, factors influencing prognosis and emergency medical services. The research frontier identification revealed that 7 categories were classified, including therapeutic hypothermia, emergency medical services, airway management, myocardial infarction, extracorporeal cardiopulmonary resuscitation, stroke foundation and trial. The burst detection analysis revealed that percutaneous coronary intervention, neurologic outcome, COVID-19 and extracorporeal cardiopulmonary resuscitation are issues that should be given continual attention in the future. This bibliometric analysis may reflect the current status and future frontiers of OHCA research.

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.

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.

Content validation of the HeartRunner questionnaire to volunteer responders dispatched to out-of-hospital cardiac arrests: A qualitative study

Aim

To increase survival after out-of-hospital cardiac arrest (OHCA) in Denmark, volunteer responders are activated through a smartphone application (HeartRunner app) to quickly locate an automated external defibrillator (AED) and assist with cardiopulmonary resuscitation (CPR). All dispatched volunteer responders who have been activated by the app receive a follow-up questionnaire to evaluate their participation in the programme. The content of the questionnaire has never been thoroughly evaluated. We therefore aimed to validate the content of the questionnaire.

Methods

Content validity was evaluated qualitatively. It was based on individual interviews with three experts, along with three focus group interviews and five individual interviews using cognitive interview technique, with a total of 19 volunteer responders. The interviews were also used to inform refinements of the questionnaire to reach improvements in content validity.

Results

The initial questionnaire consisted of 23 items. After the content validation process, the questionnaire consisted of 32 items; with the addition of 9 new items. Specifically, some original items were merged into one item or divided into separate items. Moreover, we revised the order of items, some sentences were rephrased or reworded, an introduction and headlines to different sections were added, and skip logic were incorporated to hide non-relevant items.

Conclusion

Our findings support the importance of validating questionnaires to ensure accuracy of survey instruments. Validation led to modifications of the questionnaire, and we propose a new version of the HeartRunner questionnaire. Our findings support the content validity of the final HeartRunner questionnaire. The questionnaire may allow the collection of quality data to evaluate and improve volunteer responder programmes.

Determinants of health-related quality of life after out-of-hospital cardiac arrest (OHCA): A systematic review

OBJECTIVE

With a growing number of out-of-hospital cardiac arrest (OHCA) survivors globally, the focus of OHCA management has now broadened to survivorship. An outcome central to survivorship is health-related quality of life (HRQoL). This systematic review aimed to synthesise evidence related to the determinants of HRQoL of OHCA survivors.

METHODS

We systematically searched MEDLINE, Embase, and Scopus from inception to 15 August 2022 to identify studies investigating the association of at least one determinant and HRQoL in adult OHCA survivors. All articles were independently reviewed by two investigators. We abstracted data pertaining to determinants and classified them using a well-established HRQoL theoretical framework - the Wilson and Cleary (revised) model.

RESULTS

31 articles assessing a total of 35 determinants were included. Determinants were classified into the five domains in the HRQoL model. 26 studies assessed determinants related to individual characteristics (n=3), 12 studied biological function (n=7), nine studied symptoms (n=3), 16 studied functioning (n=5), and 35 studied characteristics of the environment (n=17). In studies that included multivariable analyses, most reported that individual characteristics (older age, female sex), symptoms (anxiety, depression), and functioning (impaired neurocognitive function) were significantly associated with poorer HRQoL.

CONCLUSIONS

Individual characteristics, symptoms, and functioning played significant roles in explaining the variability in HRQoL. Significant non-modifiable determinants such as age and sex could be used to identify populations at risk of poorer HRQoL, while significant modifiable determinants such as psychological health and neurocognitive functioning could serve as targets for post-discharge screening and rehabilitation plans. PROSPERO registration number: CRD42022359303.

Modification of termination of resuscitation rule with compression time interval in South Korea

This study aimed to validate the predictive performance of the termination of resuscitation (TOR) rule and examine the compression time interval (CTI) as a criterion for modifying the rule. This retrospective observational study analyzed adult out-of-hospital cardiac arrest (OHCA) patients attended by emergency medical service (EMS) providers in mixed urban-rural areas in Korea in 2020 and 2021. We evaluated the predictive performance of basic life support (BLS) and the Korean Cardiac Arrest Research Consortium (KoCARC) TOR rule using the false-positive rate (FPR) and positive predictive value (PPV). We modified the age cutoff criterion and examined the CTI as a new criterion. According to the TOR rule, 1827 OHCA patients were classified into two groups. The predictive performance of the BLS TOR rule had an FPR of 11.7% (95% confidence interval (CI): 5.9-17.5) and PPV of 98.4% (97.6-99.2) for mortality, and an FPR of 3.6% (0.0-7.8) and PPV of 78.6% (75.9-81.3) for poor neurological outcomes at hospital discharge. The predictive performance of the KoCARC TOR rule had an FPR of 5.0% (1.1-8.9) and PPV of 98.9% (98.0-99.8) for mortality, and an FPR of 3.7% (0.0-7.8) and PPV of 50.0% (45.7-54.3) for poor neurological outcomes at hospital discharge. The modified cutoff value for age was 68 years, with an area under the receiver operating characteristic curve over 0.7. In the group that met the BLS TOR rule, the cutoff of the CTI for death was not determined and was 21 min for poor neurological outcomes. In the group that met the KoCARC TOR rule, the cutoff of the CTI for death and poor neurological outcomes at the time of hospital discharge was 25 min and 21 min, respectively. The BLS TOR and KoCARC TOR rules showed inappropriate predictive performance for mortality and poor neurological outcomes. However, the predictive performance of the TOR rule could be supplemented by modifying the age criterion and adding the CTI criterion of the KoCARC.

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.

Impact of COVID-19 on Out-of-Hospital Cardiac Arrest in Korea

BACKGROUND

Coronavirus disease 2019 (COVID-19) is a global public health crisis that has had a significant impact on emergency medical services (EMS). Several studies have reported an increase in the incidence of out-of-hospital cardiac arrest (OHCA) and a decreased survival due to COVID-19, which has been limited to a short period or has been reported in some regions. This study aimed to investigate the effect of COVID-19 on OHCA patients using a nationwide database.

METHODS

We included adult OHCA patients treated by EMS providers from January 19, 2019 to January 20, 2021. The years before and after the first confirmed case in Korea were set as the non-COVID-19 and COVID-19 periods, respectively. The main exposure of interest was the COVID-19 period, and the primary outcome was prehospital return of spontaneous circulation (ROSC). Other OHCA variables were compared before and after the COVID-19 pandemic and analyzed. We performed a multivariable logistic regression analysis to understand the independent effect of the COVID-19 period on prehospital ROSC.

RESULTS

The final analysis included 51,921 eligible patients, including 25,355 (48.8%) during the non-COVID-19 period and 26,566 (51.2%) during the COVID-19 period. Prehospital ROSC deteriorated during the COVID-19 period (10.2% vs. 11.1%, P = 0.001). In the main analysis, the adjusted odds ratios (AORs) for prehospital ROSC showed no significant differences between the COVID-19 and non-COVID-19 periods (AOR [95% confidence interval], 1.02 [0.96-1.09]).

CONCLUSION

This study found that the proportion of prehospital ROSC was lower during the COVID-19 period than during the non-COVID-19 period; however, there was no statistical significance when adjusting for potential confounders. Continuous efforts are needed to restore the broken chain of survival in the prehospital phase and increase the survival rate of OHCA patients.

Evaluation of optimal scene time interval for out-of-hospital cardiac arrest using a deep neural network

AIM

This study aims to develop a cardiac arrest prediction model using deep learning (CAPD) algorithm and to validate the developed algorithm by evaluating the change in out-of-hospital cardiac arrest patient prognosis according to the increase in scene time interval (STI).

METHODS

We conducted a retrospective cohort study using smart advanced life support trial data collected by the National Emergency Center from January 2016 to December 2019. The smart advanced life support data were randomly partitioned into derivation and validation datasets. The performance of the CAPD model using the patient's age, sex, event witness, bystander cardiopulmonary resuscitation (CPR), administration of epinephrine, initial shockable rhythm, prehospital defibrillation, provision of advanced life support, response time interval, and STI as prediction variables for prediction of a patient's prognosis was compared with conventional machine learning methods. After fixing other values of the input data, the changes in prognosis of the patient with respect to the increase in STI was observed.

RESULTS

A total of 16,992 patients were included in this study. The area under the receiver operating characteristic curve values for predicting prehospital return of spontaneous circulation (ROSC) and favorable neurological outcomes were 0.828 (95% confidence interval 0.826-0.830) and 0.907 (0.914-0.910), respectively. Our algorithm significantly outperformed other artificial intelligence algorithms and conventional methods. The neurological recovery rate was predicted to decrease to 1/3 of that at the beginning of cardiopulmonary resuscitation when the STI was 28 min, and the prehospital ROSC was predicted to decrease to 1/2 of its initial level when the STI was 30 min.

CONCLUSION

The CAPD exhibits potential and effectiveness in identifying patients with ROSC and favorable neurological outcomes for prehospital resuscitation.

Recurrent Out-of-Hospital Sudden Cardiac Arrest: Prevalence and Clinical Factors

BACKGROUND

Despite improvements in management following survival from sudden cardiac arrest (SCA) and wide availability of implantable cardioverter defibrillators for secondary prevention, a subgroup of individuals will suffer multiple distinct episodes of SCA. The objective of this study was to characterize and evaluate the burden of recurrent out-of-hospital SCA among survivors of SCA in a single large US community.

METHODS

SCA cases were prospectively ascertained in the Oregon Sudden Unexpected Death Study. Individuals that experienced recurrent SCA were identified both prospectively and retrospectively.

RESULTS

We ascertained 6649 individuals with SCA (2002-2020) and 924 (14%) survived to hospital discharge. Of these, 88 survivors (10%) experienced recurrent SCA. Of the nonsurvivors (n=5725), 35 had suffered a recurrent SCA. Of the total 123 SCA cases with recurrent SCA, >60% occurred at least 1 year after the initial SCA (median 23 months, range: 6 days to 31 years). SCA occurred despite a secondary prevention implantable cardioverter defibrillator in 22% (n=26). Prevalence of coronary disease (36% versus 25%), hypertension (69% versus 43%), diabetes (44% versus 21%), and chronic kidney disease (35% versus 14%) was significantly higher in recurrent SCA versus single SCA survivors (n=80, P=0.01). Among individuals with no secondary prevention implantable cardioverter defibrillators before recurrent SCA, the majority had apparently reversible etiologies identified at initial SCA, with one-quarter undergoing coronary revascularization and over half diagnosed with noncoronary cardiac etiologies.

CONCLUSIONS

At least 10% of SCA survivors had recurrent SCA, and a large subgroup suffered their repeat SCA despite treatment for an apparently reversible etiology. A renewed focus on careful assessment of cardiac substrate as well as management of coronary disease, hypertension, diabetes, and chronic kidney disease in SCA survivors could reduce recurrent SCA.

An epidemiological assessment of choking-induced out-of-hospital cardiac arrest: A post hoc analysis of the SOS-KANTO 2012 study

OBJECTIVES

The aim of this study was to reveal the neurological outcomes of choking-induced out-of-hospital cardiac arrest (OHCA) and evaluate the presence of witnesses, cardiopulmonary resuscitation (CPR) performed by a witness (bystander-witnessed CPR), and the proportion of patients with favourable neurological outcomes by the time from CPR by emergency medical services (EMS) to the return of spontaneous circulation (ROSC) (CPR-ROSC time).

METHODS

We retrospectively analysed the SOS-KANTO 2012 database, which included data of 16,452 OHCAs in Japan. We selected choking-induced OHCA patients aged ≥ 20 years. We evaluated the neurological outcomes at 1 month with the Cerebral Performance Category (CPC). We defined favourable neurological outcomes (CPCs: 1-2) and present the outcomes with descriptive statistics.

RESULTS

Of 1,045 choking-induced OHCA patients, 18 (1.7%) had a favourable neurological outcome. Of 1,045 OHCAs, 757 (72.6%) were witnessed, and 375 (36.0%) underwent bystander-witnessed CPR. Of the 18 OHCAs with favourable outcomes, 17 (94.4%) were witnessed, and 11 (61.1%) underwent bystander-witnessed CPR. With a CPR-ROSC time of 0-5 minutes, the proportion of patients with favourable neurological outcomes was 29.7%, ranging from 0% to 6% in the following time groups.

CONCLUSIONS

The neurological outcome of choking-induced OHCA was poor. The neurological outcomes deteriorated rapidly from 5 minutes after the initiation of CPR by EMS. The presence of witnesses and bystander-witnessed CPR may be factors that contribute to improved outcomes, but the effects were not remarkable. As another approach to reduce deaths due to choking, citizen education for the prevention of choking may be effective.

Impact of Cardiopulmonary Resuscitation on Emergency Medical Staff—Romanian Perspective (IRESUS-EMS)

Background: Unnecessary resuscitation is defined as putting in a disproportionate amount of effort compared to the patients’ prognosis and chance of survival. The primary objective of this study was to determine the number of resuscitations perceived as unnecessary by emergency medical personnel and to correlate it with the characteristics of resuscitation team members, patient particularities and organizational factors related to the professional environment. Methods: This was a prospective cross-sectional study carried out in the emergency department of a university hospital, exploring the perception of the uselessness of cardiopulmonary resuscitation (CPR) through the completion of a questionnaire. Results: In total, 70.37% of respondents are often involved in CPR attempts in which the efforts made are disproportionate compared to the patients’ expected prognosis, in terms of survival or quality of life. The presence of a non-shockable rhythm increased, by two times, the chances of medical staff finding it unnecessary to initiate CPR. Conclusions: The current study was the first in Romania to investigate the perception of unnecessary CPR, based on the recollection of the last resuscitation performed by the emergency medical staff. The objective criteria related to the patient were the most important predictors for assessing the adequacy of the decision to initiate CPR.

External validation of the Survival After ROSC in Cardiac Arrest (SARICA) score for predicting survival after return of spontaneous circulation using multinational pan-asian cohorts

Aim

Accurate and timely prognostication of patients with out-of-hospital cardiac arrest (OHCA) who attain return of spontaneous circulation (ROSC) is crucial in clinical decision-making, resource allocation, and communication with family. A clinical decision tool, Survival After ROSC in Cardiac Arrest (SARICA), was recently developed, showing excellent performance on internal validation. We aimed to externally validate SARICA in multinational cohorts within the Pan-Asian Resuscitation Outcomes Study.

Materials and methods

This was an international, retrospective cohort study of patients who attained ROSC after OHCA in the Asia Pacific between January 2009 and August 2018. Pediatric (age <18 years) and traumatic arrests were excluded. The SARICA score was calculated for each patient. The primary outcome was survival. We used receiver operating characteristics (ROC) analysis to calculate the model performance of the SARICA score in predicting survival. A calibration belt plot was used to assess calibration.

Results

Out of 207,450 cases of OHCA, 24,897 cases from Taiwan, Japan and South Korea were eligible for inclusion. Of this validation cohort, 30.4% survived. The median SARICA score was 4. Area under the ROC curve (AUC) was 0.759 (95% confidence interval, CI 0.753–0.766) for the total population. A higher AUC was observed in subgroups that received bystander CPR (AUC 0.791, 95% CI 0.782–0.801) and of presumed cardiac etiology (AUC 0.790, 95% CI 0.782–0.797). The model was well-calibrated.

Conclusion

This external validation study of SARICA demonstrated high model performance in a multinational Pan-Asian cohort. Further modification and validation in other populations can be performed to assess its readiness for clinical translation.

Readiness of Bystander Cardiopulmonary Resuscitation (BCPR) during the COVID-19 Pandemic: A Review

Early cardiopulmonary resuscitation (CPR) is a strong link in the of survival for sudden cardiac arrest. Hence, bystander CPR (BPCR) plays an important role in curbing mortality and morbidity from out-of-hospital sudden cardiac arrest. However, the recent global Coronavirus disease 2019 (COVID-19) pandemic has impacted both public training and confidence in performing out-of-hospital CPR. This paper reviews detailed information from databases including Google Scholar, Scopus, PubMed and Web of Science on the readiness of BCPR during the pandemic. We also discussed the challenges bystanders encountered during the COVID-19 pandemic and the precautions to follow. Finally, we also highlighted the limitations which would benefit future endeavours in establishing well-planned and sustainable CPR training programs for the public. Therefore, regardless of the existing COVID-19 pandemic, BCPR must be emphasised to curb out-of-hospital cardiac arrest (OHCA) mortality.

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

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

Development and validation of an interpretable prehospital return of spontaneous circulation (P-ROSC) score for patients with out-of-hospital cardiac arrest using machine learning: A retrospective study

BACKGROUND

Return of spontaneous circulation (ROSC) before arrival at the emergency department is an early indicator of successful resuscitation in out-of-hospital cardiac arrest (OHCA). Several ROSC prediction scores have been developed with European cohorts, with unclear applicability in Asian settings. We aimed to develop an interpretable prehospital ROSC (P-ROSC) score for ROSC prediction based on patients with OHCA in Asia.

METHODS

This retrospective study examined patients who suffered from OHCA between Jan 1, 2009 and Jun 17, 2018 using data recorded in the Pan-Asian Resuscitation Outcomes Study (PAROS) registry. AutoScore, an interpretable machine learning framework, was used to develop P-ROSC. On the same cohort, the P-ROSC was compared with two clinical scores, the RACA and the UB-ROSC. The predictive power was evaluated using the area under the curve (AUC) in the receiver operating characteristic analysis.

FINDINGS

170,678 cases were included, of which 14,104 (8.26%) attained prehospital ROSC. The P-ROSC score identified a new variable, prehospital drug administration, which was not included in the RACA score or the UB-ROSC score. Using only five variables, the P-ROSC score achieved an AUC of 0.806 (95% confidence interval [CI] 0.799-0.814), outperforming both RACA and UB-ROSC with AUCs of 0.773 (95% CI 0.765-0.782) and 0.728 (95% CI 0.718-0.738), respectively.

INTERPRETATION

The P-ROSC score is a practical and easily interpreted tool for predicting the probability of prehospital ROSC.

FUNDING

This research received funding from SingHealth Duke-NUS ACP Programme Funding (15/FY2020/P2/06-A79).

Activation of Citizen Responders to Out‐of‐Hospital Cardiac Arrest During the COVID‐19 Outbreak in Denmark 2020

Background

Little is known about how COVID‐19 influenced engagement of citizen responders dispatched to out‐of‐hospital cardiac arrest (OHCA) by a smartphone application. The objective was to describe and analyze the Danish Citizen Responder Program and bystander interventions (both citizen responders and nondispatched bystanders) during the first COVID‐19 lockdown in 2020.

Methods and Results

All OHCAs from January 1, 2020, to June 30, 2020, with citizen responder activation in 2 regions of Denmark were included. We compared citizen responder engagement for OHCA in the nonlockdown period (January 1, 2020, to March 10, 2020, and April 21, 2020, to June 30, 2020) with the lockdown period (March 11, 2020, to April 20, 2020). Data are displayed in the order lockdown versus nonlockdown period. Bystander cardiopulmonary resuscitation rates did not differ in the 2 periods (99% versus 92%; P=0.07). Bystander defibrillation (9% versus 14%; P=0.4) or return‐of‐spontaneous circulation (23% versus 23%; P=1.0) also did not differ. A similar amount of citizen responders accepted alarms during the lockdown (6 per alarm; interquartile range, 6) compared with the nonlockdown period (5 per alarm; interquartile range, 5) (P=0.05). More citizen responders reported performing chest‐compression‐only cardiopulmonary resuscitation during lockdown compared with nonlockdown (79% versus 59%; P=0.0029), whereas fewer performed standardized cardiopulmonary resuscitation, including ventilations (19% versus 38%; P=0.0061). Finally, during lockdown, more citizen responders reported being not psychologically affected by attending an OHCA compared with nonlockdown period (68% versus 56%; P<0.0001). Likewise, fewer reported being mildly affected during lockdown (26%) compared with nonlockdown (35%) (P=0.003).

Conclusions

The COVID‐19 lockdown in Denmark was not associated with decreased bystander‐initiated resuscitation in OHCAs attended by citizen responders.

Gender disparities among adult recipients of layperson bystander cardiopulmonary resuscitation by location of cardiac arrest in Pan-Asian communities: A registry-based study

BACKGROUND

Bystander cardiopulmonary resuscitation (BCPR) is a critical component of the 'chain of survival' in reducing mortality among out-of-hospital cardiac arrest (OHCA) victims. Inconsistent findings on gender disparities among adult recipients of layperson BCPR have been reported in the literature. We aimed to fill this knowledge gap by investigating the extent of gender disparities in a cross-national setting within Pan-Asian communities.

METHODS

We utilised data collected from the Pan-Asian Resuscitation Outcomes Study (PAROS), an international, multicentre, prospective study conducted between 2009 and 2018. We included all OHCA cases with non-traumatic arrest aetiology transported by emergency medical services and excluded study sites that did not consistently collect information about the location of cardiac arrest. Logistic regression was used to analyse the association between gender and BCPR, stratified by location.

FINDINGS

We analysed a cohort of 56,192 OHCA cases with an overall BCPR rate of 36.2% (20,329/56,192). At public locations, the BCPR rate was 31.2% (631/2022) for female and 36.4% (3235/8892) for male OHCA victims; while at home, the rate was 38.3% (6838/17,842) for females and 35.1% (9625/27,436) for males. Controlling for site differences and several factors in multivariable logistic regression, we found females less likely to receive BCPR than males in public locations (odds ratio [OR]=0.89, 95% confidence interval [CI]: 0.70-0.99), but more likely to receive BCPR at home (OR=1.16, 95% CI: 1.11-1.21).

INTERPRETATION

In Pan-Asian communities, gender differences exist in adult recipients of BCPR and differ between home and public locations. Future studies should account for additional information on bystanders and societal factors to identify targets for interventions.

FUNDING

The study was supported by grants from the National Medical Research Council (NMRC/CSA/0049/2013) and Laerdal Foundation (20040).

Global prevalence of cardiopulmonary resuscitation training among the general public: a scoping review

A scoping review was conducted to identify, map, and analyze international evidence from studies investigating the prevalence of community cardiopulmonary resuscitation (CPR) training. We searched major bibliographic databases and grey literature for original studies evaluating the prevalence of CPR training in the general population. Studies published from January 2000 to October 2020 were included without language or publication type restrictions. Seventy-three eligible papers reported a total of 61 population-based surveys conducted in 29 countries. More than three-fourths of the surveys were conducted in countries with high-income economies, and none in low-income countries. Over half of the surveys were at a subnational level. Globally, the proportion of laypeople trained in CPR varied greatly (median, 40%). For high-income countries, the median percentage was twice as high as that of upper middle-income countries (50% vs. 23%). The studies used heterogeneous survey methods and reporting patterns. Key methodological aspects were frequently not described. In summary, few studies have assessed CPR training prevalence among the general public. The rates of resuscitation training for the vast majority of countries remain unknown. High heterogeneity of studies precludes a reliable interpretation of the research. International Utstein-style consensus guidelines are needed to inform future research and reporting of public resuscitation training worldwide.

Maximum expected survival rate model for public access defibrillator placement

AIM

Mathematical optimization of automated external defibrillator (AED) placement has demonstrated potential to improve survival of out-of-hospital cardiac arrest (OHCA). Existing models mostly aim to improve accessibility based on coverage radius and do not account for detailed impact of delayed defibrillation on survival. We aimed to predict OHCA survival based on time to defibrillation and developed an AED placement model to directly maximize the expected survival rate.

METHODS

We stratified OHCAs occurring in Singapore (2010-2017) based on time to defibrillation and developed a regression model to predict the Utstein survival rate. We then developed a novel AED placement model, the maximum expected survival rate (MESR) model. We compared the performance of MESR with a maximum coverage model developed for Canada that was shown to be generalizable to other settings (Denmark). The survival gain of MESR was assessed through 10-fold cross-validation for placement of 20 to 1000 new AEDs in Singapore. Statistical analysis was performed using χ² and McNemar's tests.

RESULTS

During the study period, 15,345 OHCAs occurred. The power-law approximation with R² of 91.33% performed best among investigated models. It predicted a survival of 54.9% with defibrillation within the first two minutes after collapse that was reduced by more than 60% without defibrillation within the first 4 minutes. MESR outperformed the maximum coverage model with P-value < 0.05 (<0.0001 in 22 of 30 experiments).

CONCLUSION

We developed a novel AED placement model based on the impact of time to defibrillation on OHCA outcomes. Mathematical optimization can improve OHCA survival.

Early Changes in Patient Access Interval during the COVID-19 Pandemic

Background: COVID-19 was first reported in the United States in January 2020. Its spread throughout the country required EMS systems to rapidly adapt to patient needs while protecting EMS personnel. EMS agencies developed protocols requiring personnel to don enhanced personal protective equipment prior to patient contact. We hypothesized that the Patient Access Interval (PAI), defined as the time from wheels stopped on scene to initial patient contact, had increased during the COVID pandemic. This had the potential to affect patient outcomes, particularly in time-sensitive emergencies such as cardiac arrest or respiratory distress. Methods: This retrospective cohort study used commercial ambulance data from the four largest cities in Connecticut at two different time points: (Pre-COVID) March-May 2019, and (COVID) March-May 2020. PAI was calculated from contemporaneously reported scene times. Total cases were analyzed, and sub-analyses performed for calls located at extended care facilities (ECFs), for all emergent (Echo/Delta) calls, and for medical cardiac arrest calls. Results: 92,846 total cases were evaluated: 50,083 from 2019, and 42,763 from 2020. Cases that did not include necessary time data for PAI were removed, yielding 75,796 total cases (41,852 from 2019, 33,944 from 2020). The average PAI increased from 1 minute 55 seconds (1 m:55s) Pre-COVID to 2 m:18s COVID. ECF PAI increased from 2 m:39s to 3 m:42s. Echo/Delta PAI increased from 1 m:42s to 2 m:07s. Medical cardiac arrest PAI increased from 1 m:27s to 2 m:04s, and ECF cardiac arrest PAI increased from 2 m:18s to 4 m:35s (all comparisons p < 0.01). Conclusions: There were statistically significant increases in all studied PAIs during COVID. The 23 second increase in PAI for all calls may not have been clinically significant in most cases; however, for life-threatening patient presentations, the increase may have been particularly relevant. The increased PAI was compounded in the ECF environment, possibly due to state-mandated screening and temperature checks of EMS personnel before entering facilities. This was highlighted in the ECF cardiac arrest data, which demonstrated a clinically significant increase in PAI of 2m:17s. While this study was limited by the accuracy of contemporaneous time reports by EMS, the results support our hypothesis that PAI had increased during the COVID pandemic.

"Time that save lives" while waiting for ambulance in rural environments

AIM

Firefighters perform first aid before the ambulance arrives in areas with a long response time in Sweden; this is called 'While Waiting for the Ambulance' (WWFA). The aim was to describe WWFA assignments in rural environments, focusing on frequency, event time, actions and survival >30 days after cardiopulmonary resuscitation (CPR) was performed.

METHODS

Retrospective descriptive and comparative design.

RESULTS

Firefighters in the northern part of Sweden were involved in 518 WWFA assignments between 2012 and 2016. From alarm call until ambulance dispatch, median time was 2:20 min; for firefighters, nearly four minutes. Median dispatch time at out-of-hospital cardiac arrests (OHCA) (n = 52) was 1:40 min for ambulance and three minutes for firefighters. Maximal dispatch time was nearly 10 min for ambulance and 44 min for firefighters. Firefighters arrived first at the scene, after 17 min' median, for 95 % of assignments, while the ambulance took nearly twice the amount of time. In OHCA situations, time for firefighters was over 19 min versus ambulance at nearly twice the time. CPR was terminated by ambulance staff at 83% (n = 43) of 52 when firefighters performed prolonged CPR. Return to spontaneous circulation after OHCA was 17%, and 9% were alive after >30 days.

CONCLUSION

The efficiency of incident time and utilisation rate for WWFA assignments can be increased for the benefit of affected persons, especially in OHCA.

Effectiveness of a Dispatcher-Assisted Cardiopulmonary Resuscitation Program Developed by the Thailand National Institute of Emergency Medicine (NIEMS)

BACKGROUND

Out-of-hospital cardiac arrest (OHCA) is a life-threatening condition with an overall survival rate that generally does not exceed 10%. Several factors play essential roles in increasing survival among patients experiencing cardiac arrest outside the hospital. Previous studies have reported that implementing a dispatcher-assisted cardiopulmonary resuscitation (DA-CPR) program increases bystander CPR, quality of chest compressions, and patient survival. This study aimed to assess the effectiveness of a DA-CPR program developed by the Thailand National Institute for Emergency Medicine (NIEMS).

METHODS

This was an experimental study using a manikin model. The participants comprised both health care providers and non-health care providers aged 18 to 60 years. They were randomly assigned to either the DA-CPR group or the uninstructed CPR (U-CPR) group and performed chest compressions on a manikin model for two minutes. The sequentially numbered, opaque, sealed envelope method was used for randomization in blocks of four with a ratio of 1:1.

RESULTS

There were 100 participants in this study (49 in the DA-CPR group and 51 in the U-CPR group). Time to initiate chest compressions was statistically significantly longer in the DA-CPR group than in the U-CPR group (85.82 [SD = 32.54] seconds versus 23.94 [SD = 16.70] seconds; P <.001). However, the CPR instruction did not translate into better performance or quality of chest compressions for the overall sample or for health care or non-health care providers.

CONCLUSION

Those in the CPR-trained group applied chest compressions (initiated CPR) more quickly than those who initiated CPR based upon dispatch-based CPR instructions.

One out of three bystanders of out-of-hospital cardiac arrests shows signs of pathological psychological processing weeks after the incident - results from structured telephone interviews

Background

Witnessing an out-of-hospital cardiac arrest (OHCA) is a traumatic experience. This study analyses bystanders` psychological processing of OHCA. We examined the potential impact of bystanders performing resuscitation and the influence of the relationship between bystander and patient (stranger vs. family/friend of the patient) on the psychological processing.

Methods

A telephone interview survey with bystanders, who witnessed an OHCA of an adult patient was performed weeks after the event between December 2014 and April 2016. The semi-standardized questionnaire contained a question regarding the paramount emotion at the time of the interview. In a post-hoc analysis statements given in response were rated by independent researchers into the categories “signs of pathological psychological processing”, “physiological psychological processing” and “no signs of psychological distress due to the OHCA”.

Results

In this analysis 89 telephone interviews were included. In 27 cases (30.3%) signs of pathological psychological processing could be detected. Bystanders performing resuscitation had a higher rate of “no signs of psychological distress after witnessing OHCA” compared to those not resuscitating (54.7% vs. 26.7%, p < 0.05; relative risk 2.01; 95%CI 1.08, 3.89). No statistical significant differences in the psychological processing could be shown for gender, age, relationship to the patient, current employment in the health sector, location of cardiac arrest or number of additional bystanders.

Conclusions

One out of three bystanders of OHCA suffers signs of pathological psychological processing. This was independent of bystander´s age, gender and relationship to the patient. Performing resuscitation seems to help coping with witnessing OHCA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13049-021-00945-8.

Collaboration between emergency physicians and citizen responders in out-of-hospital cardiac arrest resuscitation

BACKGROUND

Citizen responder programmes dispatch volunteer citizens to initiate resuscitation in nearby out-of-hospital cardiac arrests (OHCA) before the Emergency Medical Services (EMS) arrival. Little is known about the interaction between citizen responders and EMS personnel during the resuscitation attempt. In the Capital Region of Denmark, emergency physicians are dispatched to all suspected OHCAs. The aim of this study was to evaluate how emergency physicians perceived the collaboration with citizen responders during resuscitation attempts.

METHOD

This cross-sectional study was conducted through an online questionnaire. It included all 65 emergency physicians at Copenhagen EMS between June 9 and December 13, 2019 (catchment area 1.8 million). The questionnaire examined how emergency physicians perceived the interaction with citizen responders at the scene of OHCA (use of citizen responders before and after EMS arrival, citizen responders' skills in cardiopulmonary resuscitation (CPR), and challenges in this setting).

RESULTS

The response rate was 87.7% (57/65). Nearly all emergency physicians (93.0%) had interacted with a citizen responder at least once. Of those 92.5%(n = 49) considered it relevant to activate citizen responders to OHCA resuscitation, and 67.9%(n = 36) reported the collaboration as helpful. When citizen responders arrived before EMS, 75.5%(n = 40) of the physicians continued to use citizen responders to assist with CPR or to carry equipment. Most (84.9%, n = 45) stated that citizen responders had the necessary skills to perform CPR. Challenges in the collaboration were described by 20.7%(n = 11) of the emergency physicians and included citizen responders being mistaken for relatives, time-consuming communication, or crowding problems during resuscitation.

CONCLUSION

Emergency physicians perceived the collaboration with citizen responders as valuable, not only for delivery of CPR, but were also considered an extra helpful resource providing non-CPR related tasks such as directing the EMS to the arrest location, carrying equipment and taking care of relatives.

Transportation during and after cardiac arrest: who, when, how and where?

PURPOSE OF REVIEW

Out-of-hospital cardiac arrest (OHCA) is the most devastating and time-critical medical emergency. Survival after OHCA requires an integrated system of care, of which transport by emergency medical services is an integral component. The transport system serves to commence and ensure uninterrupted high-quality resuscitation in suitable patients who would benefit, terminate resuscitation in those that do not, provide critical interventions, as well as convey patients to the next appropriate venue of care. We review recent evidence surrounding contemporary issues in the transport of OHCA, relating to who, where, when and how to transport these patients.

RECENT FINDINGS

We examine the clinical and systems-related evidence behind issues including: contemporary approaches to field termination of resuscitation in patients in whom continued resuscitation and transport to hospital would be medically futile, OHCA patients and organ donation, on-scene versus intra-transport resuscitation, significance of response time, intra-transport interventions (mechanical chest compression, targeted temperature management, ECMO-facilitated cardiopulmonary resuscitation), OHCA in high-rise locations and cardiac arrest centers. We highlight gaps in current knowledge and areas of active research.

SUMMARY

There remains limited evidence to guide some decisions in transporting the OHCA patient. Evidence is urgently needed to elucidate the roles of cardiac arrest centers and ECPR in OHCA.

Evidence-Based Approach to Out-of-Hospital Cardiac Arrest

Purpose of review

Out-of-hospital cardiac arrest (OHCA) is a leading cause of death. Despite improvements in the cardiac disease management, OHCA outcomes remain poor. The purpose of this review is to provide information on the management of OHCA survivors, evidence-based treatments, and current gaps in the knowledge.

Recent findings

Most common cause of death from OHCA is neurological injury followed by shock and multiorgan failure. Prognostication tools are available to help with the clinical decision-making. Taking measures to improve EMS response time, encouraging bystander CPR, early defibrillation, and targeted temperature management are shown to improve survival. Early activation of cardiac catheterization lab for coronary angiography, hemodynamic assessment, and mechanical circulatory support should be considered in patients with shockable rhythm and presumed cardiac cause, those with ST elevation, ongoing ischemia, or evidence of hemodynamic and electrical instability. Randomized controlled trials are lacking in this field and benefits of interventions should be weighed against risk of pursuing a futile treatment. COVID-19 pandemic has added new challenges to the care of OHCA patients.

Summary

Clinical decision-making to care for OHCA patients is challenging. There is a need for trials to provide evidence-based knowledge on the care of OHCA patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11936-021-00924-3.

Smartphone Activation of Citizen Responders to Facilitate Defibrillation in Out-of-Hospital Cardiac Arrest

BACKGROUND

Dispatching citizen responders through a smartphone application (app) holds the potential to increase bystander cardiopulmonary resuscitation (CPR) and defibrillation in out-of-hospital cardiac arrest (OHCA).

OBJECTIVES

This study investigated arrival at the OHCA location of app-dispatched citizen responders before the Emergency Medical Services (EMS) and the association with bystander CPR and bystander defibrillation.

METHODS

Suspected OHCAs with alerted citizen responders from September 1, 2017, to August 31, 2018, were included. Citizen responders located 1.8 km (1.1 miles) from the OHCA were dispatched to start CPR or retrieve an automated external defibrillator. OHCAs where at least 1 citizen responder arrived before EMS were compared with OHCAs where EMS arrived first. In both groups, random bystanders could be present before the arrival of citizen responders and the EMS. Primary outcomes were bystander CPR and bystander defibrillation, which included CPR and defibrillation by citizen responders and random bystanders.

RESULTS

Citizen responders were alerted in 819 suspected OHCAs, of which 438 (53.5%) were confirmed cardiac arrests eligible for inclusion. At least 1 citizen responder arrived before EMS in 42.0% (n = 184) of all included OHCAs. When citizen responders arrived before EMS, the odds for bystander CPR increased (odds ratio: 1.76; 95% confidence interval: 1.07 to 2.91; p = 0.027) and the odds for bystander defibrillation more than tripled (odds ratio: 3.73; 95% confidence interval: 2.04 to 6.84; p < 0.001) compared with OHCAs in which citizen responders arrived after EMS.

CONCLUSIONS

Arrival of app-dispatched citizen responders before EMS was associated with increased odds for bystander CPR and a more than 3-fold increase in odds for bystander defibrillation. (The HeartRunner Trial; NCT03835403).

Implementation of a National 5-Year Plan for Prehospital Emergency Care in Singapore and Impact on Out-of-Hospital Cardiac Arrest Outcomes From 2011 to 2016

Background

Outcomes of patients from out‐of‐hospital cardiac arrest (OHCA) vary widely globally because of differences in prehospital systems of emergency care. National efforts had gone into improving OHCA outcomes in Singapore in recent years including community and prehospital initiatives. We aimed to document the impact of implementation of a national 5‐year Plan for prehospital emergency care in Singapore on OHCA outcomes from 2011 to 2016.

Methods and Results

Prospective, population‐based data of OHCA brought to Emergency Departments were obtained from the Pan‐Asian Resuscitation Outcomes Study cohort. The primary outcome was Utstein (bystander witnessed, shockable rhythm) survival‐to‐discharge or 30‐day postarrest. Mid‐year population estimates were used to calculate age‐standardized incidence. Multivariable logistic regression was performed to identify prehospital characteristics associated with survival‐to‐discharge across time. A total of 11 465 cases qualified for analysis. Age‐standardized incidence increased from 26.1 per 100 000 in 2011 to 39.2 per 100 000 in 2016. From 2011 to 2016, Utstein survival rates nearly doubled from 11.6% to 23.1% (P=0.006). Overall survival rates improved from 3.6% to 6.5% (P<0.001). Bystander cardiopulmonary resuscitation rates more than doubled from 21.9% to 56.3% and bystander automated external defibrillation rates also increased from 1.8% to 4.6%. Age ≤65 years, nonresidential location, witnessed arrest, shockable rhythm, bystander automated external defibrillation, and year 2016 were independently associated with improved survival.

Conclusions

Implementation of a national prehospital strategy doubled OHCA survival in Singapore from 2011 to 2016, along with corresponding increases in bystander cardiopulmonary resuscitation and bystander automated external defibrillation. This can be an implementation model for other systems trying to improve OHCA outcomes.

Bi-Level ventilation decreases pulmonary shunt and modulates neuroinflammation in a cardiopulmonary resuscitation model

Background

Optimal ventilation strategies during cardiopulmonary resuscitation are still heavily debated and poorly understood. So far, no convincing evidence could be presented in favour of outcome relevance and necessity of specific ventilation patterns. In recent years, alternative models to the guideline-based intermittent positive pressure ventilation (IPPV) have been proposed. In this randomized controlled trial, we evaluated a bi-level ventilation approach in a porcine model to assess possible physiological advantages for the pulmonary system as well as resulting changes in neuroinflammation compared to standard measures.

Methods

Sixteen male German landrace pigs were anesthetized and instrumented with arterial and venous catheters. Ventricular fibrillation was induced and the animals were left untreated and without ventilation for 4 minutes. After randomization, the animals were assigned to either the guideline-based group (IPPV, tidal volume 8–10 ml/kg, respiratory rate 10/min, F_iO₂1.0) or the bi-level group (inspiratory pressure levels 15–17 cmH₂O/5cmH₂O, respiratory rate 10/min, F_iO₂1.0). Mechanical chest compressions and interventional ventilation were initiated and after 5 minutes, blood samples, including ventilation/perfusion measurements via multiple inert gas elimination technique, were taken. After 8 minutes, advanced life support including adrenaline administration and defibrillations were started for up to 4 cycles. Animals achieving ROSC were monitored for 6 hours and lungs and brain tissue were harvested for further analyses.

Results

Five of the IPPV and four of the bi-level animals achieved ROSC. While there were no significant differences in gas exchange or hemodynamic values, bi-level treated animals showed less pulmonary shunt directly after ROSC and a tendency to lower inspiratory pressures during CPR. Additionally, cytokine expression of tumour necrosis factor alpha was significantly reduced in hippocampal tissue compared to IPPV animals.

Conclusion

Bi-level ventilation with a constant positive end expiratory pressure and pressure-controlled ventilation is not inferior in terms of oxygenation and decarboxylation when compared to guideline-based IPPV ventilation. Additionally, bi-level ventilation showed signs for a potentially ameliorated neurological outcome as well as less pulmonary shunt following experimental resuscitation. Given the restrictions of the animal model, these advantages should be further examined.

Getting R-AEDI to save lives in Singapore

Early cardiopulmonary resuscitation (CPR) and defibrillation prior to the arrival of emergency medical services can improve survival from out-of-hospital cardiac arrest (OHCA) with good neurological outcome. However, the rate of local bystander CPR is only 24.3% and bystander defibrillation 2.1%. In 2015, the R-AEDI (Registry for AED Integration) initiative was started to improve OHCA survival rates. R-AEDI alerts volunteers to nearby OHCA cases via the myResponder mobile application. In 2015-2017, 7,682 AEDs were mapped and made accessible via this app. Comprehensive site inspections also resulted in fewer non-functional AEDs, as AED owners were educated on the importance of the maintenance of pads and batteries. The AED heat map allows us to identify areas that are lacking in or require improved public access AED coverage. The online AED registry found in the myResponder app is useful to locate AEDs rapidly during OHCAs. More community education would improve the rate of bystander defibrillation.

Validation of the ROSC after cardiac arrest (RACA) score in Pan-Asian out-of-hospital cardiac arrest patients

AIM

Survival is the most consistently captured outcome across countries for out-of-hospital cardiac arrests (OHCA), with return of spontaneous circulation (ROSC) representing the earliest endpoint for 'unbiased' initial resuscitation success. The ROSC after cardiac arrest (RACA) score was developed to predict ROSC and has been validated in several European countries. In this study, we aimed to evaluate the performance of RACA in a Pan-Asian population.

METHODS

We conducted a retrospective analysis of data collected in the Pan-Asian Resuscitation Outcomes Study (PAROS) registry. We included OHCA cases from seven communities (Japan, South Korea, Malaysia, Singapore, Taiwan, Thailand, and United Arab Emirates) between January 2009 and December 2012. Paediatric cases, cases that were conveyed by non-emergency medical services (EMS), and cases with incomplete records were excluded from the study.

RESULTS

The RACA score showed similar discrimination performance as the original German study and various European validation studies. However, it had poor calibration with the original constant regression coefficient, which was primarily due to the low ROSC rate (8.2%) in the PAROS cohort. The calibration performance of RACA significantly improved after the constant coefficient was modified to adjust for the disparity in ROSC rates between Asia and Europe.

CONCLUSION

This is the largest validation study of the RACA score. RACA consistently performs well in both Pan-Asian and European communities and can thus be a valuable tool for evaluating EMS systems. However, to implement it, the constant coefficient has to be modified in the RACA formula with local historical data.

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

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

Lone and lonely in a double ambivalence situation as experienced by callers while waiting for the ambulance in a rural environment

BACKGROUND

In a rural environment where distances and access to ambulance resources in people's immediate area are limited, other responders like firefighters dispatched to perform a first aid before ambulance arrives in areas where a longer response time exists; an assignment called 'While Waiting for the Ambulance' (WWFA). Knowledge is limited about the experience from a caller's perspective when a person has a life-threatening condition needing emergency help and both firefighters in a WWFA assignment and ambulance staff are involved.

AIM

The aim of the study is to describe the emergency situation involving a WWFA assignment in a rural environment from the caller's perspective.

METHOD

A descriptive design using qualitative methodology with a reflective lifeworld research (RLR) approach was used for this study, including in-depth interviews with eight callers.

RESULTS

An emergency situation involving WWFA assignment in a rural environment mean a sense of being lone and lonely with a vulnerability in while waiting to hand over responsibility for the affected person. Ambivalence in several dimensions arises with simultaneous and conflicting emotions. A tension between powerlessness and power of action where the throw between doubt and hope are abrupt with a simultaneous pendulum between being in a chaos and in a calm.

CONCLUSION

A double ambivalence emerges between, on one hand feeling alone in the situation and having full control, on the other hand, with trust handing over the responsibility, thereby losing control. Contact with the emergency medical dispatcher becomes a saving lifeline to hold onto, and access to emergency help in the immediate area of WWFA is valuable and important. Trust and confidence are experienced when callers are met with empathy, regardless of personal acquaintance with arriving responders.

Mandated 30-minute Scene Time Interval Correlates With Improved Return of Spontaneous Circulation at Emergency Department Arrival: A Before and After Study

BACKGROUND

Conflicting ideas exist about whether or not Emergency Medical Service (EMS) personnel should treat a cardiac arrest on scene or transport immediately.

OBJECTIVE

Our aim was to examine patient outcomes before and after an urban EMS system implemented a protocol change mandating a 30-min scene time interval (STI) for out-of-hospital cardiac arrest (OHCA).

METHODS

This was a retrospective, single-center, observational study of OHCA patients before and after an EMS protocol change mandating resuscitation on scene. Data were retrieved from an EMS cardiac arrest database for all adults with non-traumatic OHCA between January 2015 and August 2016. Descriptive statistics were used to summarize the study population, and a regression model was used to determine the associations of the protocol with the return of spontaneous circulation (ROSC).

RESULTS

A total of 633 patients were included in the study population, which was primarily male (61.3%) with a mean age of 65 years. After the 30-min STI was implemented, ROSC from OHCA increased to 40.1% of cases compared to 27.3% before the protocol change (p = 0.001; 95% confidence interval [CI] 0.053-0.203). The STI increased from 19 min 23 s to 29 min 40 s in the pre and post periods, respectively (p < 0.001). Regression indicated that the protocol change was independently associated with an improved chance of ROSC (OR 1.81; 95% CI 1.23-2.64).

CONCLUSIONS

A protocol change mandating a 30-min STI in OHCA correlated with increased STI and increased ROSC. While increased ROSC may not always equate with positive neurologic outcome, logistic regression indicated that the protocol change was independently associated with improved ROSC at emergency department arrival.

Prediction of good neurological recovery after out-of-hospital cardiac arrest: A machine learning analysis

BACKGROUND

This study aimed to train, validate and compare predictive models that use machine learning analysis for good neurological recovery in OHCA patients.

METHODS

Adult OHCA patients who had a presumed cardiac etiology and a sustained return of spontaneous circulation between 2013 and 2016 were analyzed; 80% of the individuals were analyzed for training and 20% were analyzed for validation. We developed using six machine learning algorithms: logistic regression (LR), extreme gradient boosting (XGB), support vector machine, random forest, elastic net (EN), and neural network. Variables that could be obtained within 24 hours of the emergency department visit were used. The area under the receiver operation curve (AUROC) was calculated to assess the discrimination. Calibration was assessed by the Hosmer-Lemeshow test. Reclassification was assessed by using the continuous net reclassification index (NRI).

RESULTS

A total of 19,860 OHCA patients were included in the analysis. Of the 15,888 patients in the training group, 2228 (14.0%) had a good neurological recovery; of the 3972 patients in the validation group, 577 (14.5%) had a good neurological recovery. The LR, XGB, and EN models showed the highest discrimination powers (AUROC (95% CI)) of 0.949 (0.941-0.957) for all), and all three models were well calibrated (Hosmer-Lemeshow test: p >0.05). The XGB model reclassified patients according to their true risk better than the LR model (NRI: 0.110), but the EN model reclassified patients worse than the LR model (NRI: -1.239).

CONCLUSION

The best performing machine learning algorithm was the XGB and LR algorithm.

Advanced airway management during adult cardiac arrest: A systematic review

AIM

To systematically review the literature on advanced airway management during adult cardiac arrest in order to inform the International Liaison Committee of Resuscitation (ILCOR) consensus on science and treatment recommendations.

METHODS

The review was performed according to PRISMA guidelines and registered on PROSPERO (CRD42018115556). We searched Medline, Embase, and Evidence-Based Medicine Reviews for controlled trials and observational studies published before October 30, 2018. The population included adult patients with cardiac arrest. Two investigators reviewed studies for relevance, extracted data, and assessed the risk of bias of individual studies.

RESULTS

We included 78 observational studies and 11 controlled trials. Most of the observational studies and all of the controlled trials only included patients with out-of-hospital cardiac arrest. The risk of bias for individual observational studies was overall assessed as critical or serious, with confounding and selection bias being the primary sources of bias. Three of the controlled trials, all published in 2018, were powered for clinical outcomes with two comparing a supraglottic airway to tracheal intubation and one comparing bag-mask ventilation to tracheal intubation. All three trials had some concerns regarding risk of bias primarily due to lack of blinding and variable adherence to the protocol. Clinical and methodological heterogeneity across studies, for both the observational studies and the controlled trials, precluded any meaningful meta-analyses.

CONCLUSIONS

We identified a large number of studies related to advanced airway management in adult cardiac arrest. Three recently published, large randomized trials in out-of-hospital cardiac arrest will help to inform future guidelines. Trials of advanced airway management during in-hospital cardiac arrest are lacking.

Comparison of Outcomes and Characteristics of Emergency Medical Services (EMS)-Witnessed, Bystander-Witnessed, and Unwitnessed Out-of-Hospital Cardiac Arrests in Singapore

Objectives: The objective was to compare the survival outcomes of emergency medical services (EMS)-witnessed to bystander-witnessed, and unwitnessed out-of-hospital cardiac arrests (OHCA) in Singapore. Secondary aims are to describe the 5-year trend in survival rates of EMS-witnessed arrests. Methods: This was a retrospective analysis of the Singapore's OHCA registry data from 2011 to 2015. Excluded from the analysis were patients younger than 18 years old, arrests of traumatic etiology, resuscitation not attempted, and cases not conveyed by EMS. The primary outcome was survival to hospital discharge or 30 days post-arrest. Secondary outcomes were return of spontaneous circulation (ROSC) and survival to hospital admission. Results: 8,394 cases were analyzed, with 650 (7.7%) EMS-witnessed arrests, 4480 (53.4%) bystander-witnessed arrests, and 3264 (38.9%) unwitnessed arrests. Among EMS-witnessed arrests, the majority were presumed to be of cardiac etiology (62.8%) and the most common presenting rhythm was pulseless electrical activity (PEA; 57.2%). Survival to discharge or 30^th day post-arrest was higher in EMS-witnessed arrests compared to bystander-witnessed and unwitnessed arrests (11.2% vs. 5.3% and 1.3%, p < 0.001). Survival to discharge for EMS-witnessed cases increased from 2011 (13.2%) to 2015 (18.9%). Conclusions: EMS-witnessed OHCAs were more likely to have favorable outcomes compared to bystander-witnessed and unwitnessed OHCAs. High PEA rates in EMS-witnessed arrests were associated with older patients with underlying preexisting medical conditions. Increasing public awareness on recognition of prodromal symptoms and early activation of EMS could improve post-arrest survival and neurological outcomes of OHCA.