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STUDY OBJECTIVE: Our primary objective is to calculate the relative risk of cardiac arrests at the development guide plan (DGP) (equivalent to census tract) level in a city-state, Singapore, and examine its relationship with key area-level population characteristics. METHODS: This was an observational ecological study design. We calculated the relative risk as the ratio of the observed and population standardized expected counts of out-of-hospital cardiac arrests in Singapore, aggregated at DGP level. Data were collected from October 2001 to October 2004. We used conditional autoregressive spatial models to examine the predictors of increased risk at the DGP level. RESULTS: We found a spatial distribution of cardiac arrests, with an unexpected cluster caused by nonresident arrests occurring at the international airport. The risk of out-of-hospital cardiac arrest more than doubled, 2.35 (95% confidence interval [CI] 1.28 to 4.48), for each 5-point increase in the proportion of people aged 65 years and older. For each 5-point increase in the proportion of Chinese individuals living in a DGP, the risk of out-of-hospital cardiac arrest was reduced by a factor of 0.8 (95% CI 0.7 to 0.9). The risk of out-of-hospital cardiac arrest increased by 1.49-fold (95% CI 1.18 to 1.82) for every 5-point increase in the proportion of households with no family nucleus (live alone). When restricted to residential cases of out-of-hospital cardiac arrest, none of the variables remained significant, possibly because of small sample size. CONCLUSION: The risk of cardiac arrests could be related to the age and racial and family structure of DGPs in Singapore. This article models how such data can help to direct public health education, cardiopulmonary resuscitation training, and public access defibrillation programs in other health systems. [ABSTRACT FROM AUTHOR]

Background: Historically in Singapore, all out-of-hospital cardiac arrests (OHCA) were transported to hospital for pronouncement of death. A 'Termination of Resuscitation' (TOR) protocol, implemented from 2019 onwards, enables emergency responders to pronounce death at-scene in Singapore. This study aims to evaluate the cost-effectiveness of the TOR protocol for OHCA management., Methods: Adopting a healthcare provider's perspective, a Markov model was developed to evaluate three competing options: No TOR, Observed TOR reflecting existing practice, and Full TOR if TOR is exercised fully. The model had a cycle duration of 30 days after the initial state of having a cardiac arrest, and was evaluated over a 10-year time horizon. Probabilistic sensitivity analysis was performed to account for uncertainties. The costs per quality adjusted life years (QALY) was calculated., Results: A total of 3,695 OHCA cases eligible for the TOR protocol were analysed; mean age of 73.0 ± 15.5 years. For every 10,000 hypothetical patients, Observed TOR and Full TOR had more deaths by approximately 19 and 31 patients, respectively, compared to No TOR. Full TOR had the least costs and QALYs at $19,633,369 (95% Uncertainty Interval (UI) 19,469,973 to 19,796,764) and 0 QALYs. If TOR is exercised for every eligible case, it could expect to save approximately $400,440 per QALY loss compared to No TOR, and $821,151 per QALY loss compared to Observed TOR., Conclusion: The application of the TOR protocol for the management of OHCA was found to be cost-effective within acceptable willingness-to-pay thresholds, providing some justification for sustainable adoption., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Background: NULL-PLEASE is a simple and accurate clinical scoring system developed in a Western cohort of patients with out-of-hospital cardiac arrest (OHCA). The need for blood test results limits its use in early stages of care. We adapted and validated the NULL-EASE score (without laboratory tests) in an independent, multiethnic Asian cohort of patients with out-of-hospital cardiac arrest., Methods and Results: Using the Singapore OHCA registry, we included consecutive adult patients with out-of-hospital cardiac arrest who survived to hospital admission between April 2010 to December 2020. In-hospital mortality was the primary outcome. Logistic regression analyses were performed with STATA MP v18. Of 3274 patients (median age 64, interquartile range 54-75; 67.9% male) included in the study, 2476 (75.6%) had in-hospital mortality. NULL-EASE score was significantly lower in survivors compared with nonsurvivors (median [inter quartile range] 3 [1-4] versus 6 [4-7]; P <0.001) and strongly predictive of mortality (area under receiver operating characteristic, 0.81 [95% CI, 0.79-0.83]). Patients with a score of ≥3 had higher odds of mortality (adjusted odds ratio, 8.11 [95% CI, 6.57-10.00]) when compared with those with lower scores, after adjusting for sex, residential arrest, diabetes, respiratory disease, and stroke. A cutoff value of ≥3 predicted mortality with 92.2% sensitivity, 84.1% positive predictive value, 46.1% specificity, and 65.5% negative predictive value. NULL-EASE score performed better in younger compared with older patients (area under receiver operating characteristic, 0.82 versus 0.77, P =0.008)., Conclusions: The NULL-EASE score has good discriminative performance (sensitivity and accuracy) in our multiethnic Asian cohort, but the cutoff of ≥3 falls short of the desired level of specificity for therapeutic decision-making.

Background: Shock-refractory ventricular fibrillation (VF) or ventricular tachycardia (VT) is a treatment challenge in out-of-hospital cardiac arrest (OHCA). This study aimed to develop and validate machine learning models that could be implemented by emergency medical services (EMS) to predict refractory VF/VT in OHCA patients., Methods: This was a retrospective study examining adult non-traumatic OHCA patients brought into the emergency department by Singapore EMS from the Pan-Asian Resuscitation Outcomes Study (PAROS) registry. Data from April 2010 to March 2020 were extracted for this study. Refractory VF/VT was defined as VF/VT persisting or recurring after at least one shock. Features were selected based on expert clinical opinion and availability to dispatch prior to arrival at scene. Multivariable logistic regression (MVR), LASSO and random forest (RF) models were investigated. Model performance was evaluated using receiver operator characteristic (ROC) area under curve (AUC) analysis and calibration plots., Results: 20,713 patients were included in this study, of which 860 (4.1%) fulfilled the criteria for refractory VF/VT. All models performed comparably and were moderately well-calibrated. ROC-AUC were 0.732 (95% CI, 0.695 - 0.769) for MVR, 0.738 (95% CI, 0.701 - 0.774) for LASSO, and 0.731 (95% CI, 0.690 - 0.773) for RF. The shared important predictors across all models included male gender and public location., Conclusion: The machine learning models developed have potential clinical utility to improve outcomes in cases of refractory VF/VT OHCA. Prediction of refractory VF/VT prior to arrival at patient's side may allow for increased options for intervention both by EMS and tertiary care centres., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: YO has received a research grant from the ZOLL Foundation and an overseas scholarship from the FUKUDA Foundation for Medical Technology and the International Medical Research Foundation. MEHO reports grants from the Laerdal Foundation, Laerdal Medical, and Ramsey Social Justice Foundation for funding of the Pan-Asian Resuscitation Outcomes Study; an advisory relationship with Global Healthcare SG, a commercial entity that manufactures cooling devices; and funding from Laerdal Medical on an observation program to their Community CPR Training Centre Research Program in Norway. MEHO is a Scientific Advisor to TIIM Healthcare SG and Global Healthcare SG. These organizations have no role in the design of the study, the collection, analysis, or interpretation of data, or in writing the manuscript. All other authors reported no competing interests., (© 2024 The Authors.)

Objectives: With more elderly presenting with Out-of-Hospital Cardiac Arrests (OHCAs) globally, neurologically intact survival (NIS) should be the aim of resuscitation. We aimed to study the trend of OHCA amongst elderly in a large Asian registry to identify if age is independently associated with NIS and factors associated with NIS., Methods: All adult OHCAs aged ≥18 years attended by emergency medical services (EMS) from April 2010 to December 2019 in Singapore was extracted from the Pan-Asian Resuscitation Outcomes Study (PAROS) registry. Cases pronounced dead at scene, non-EMS transported, traumatic OHCAs and OHCAs in ambulances were excluded. Patient characteristics and outcomes were compared across four age categories (18-64, 65-79, 80-89, ≥90). Multivariable logistic regression analysis determined the factors associated with NIS., Results: 19,519 eligible cases were analyzed. OHCA incidence increased with age almost doubling in octogenarians (from 312/100,000 in 2011 to 652/100,000 in 2019) and tripling in those ≥90 years (from 458/100,000 in 2011 to 1271/100,000 in 2019). The proportion of patients with NIS improved over time for the 18-64, 65-79- and 80-89-years age groups, with the greatest improvement in the youngest group. NIS decreased with each increasing year of age and minute of response time. NIS increased in the arrests of presumed cardiac etiology, witnessed and bystander CPR., Conclusions: Survival with good outcomes has increased even amongst the elderly. Regardless of age, NIS is possible with good-quality CPR, highlighting its importance. End-of-life planning is a complex yet necessary decision that requires qualitative exploration with elderly, their families and care providers., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: MEH Ong reports grants from the Laerdal Foundation, Laerdal Medical, and Ramsey Social Justice Foundation for funding of the Pan-Asian Resuscitation Outcomes Study; an advisory relationship with Global Healthcare SG, a commercial entity that manufactures cooling devices. MEH Ong has a licensing agreement with ZOLL Medical Corporation and patent filed (Application no: 13/047,348) for a “Method of predicting acute cardiopulmonary events and survivability of a patient.” He is also the co-founder and scientific advisor of TIIM Healthcare, a commercial entity which develops real-time prediction and risk stratification solutions for triage. All other authors have no conflict of interest to disclose., (© 2024 The Author(s).)

Background: Previous research indicated outcomes among refractory out-of-hospital cardiac arrest (OHCA) patients with initial shockable rhythm were different in Singapore and Osaka, Japan, possibly due to the differences in access to extracorporeal cardiopulmonary resuscitation. However, this previous study had a risk of selection bias. To address this concern, this study aimed to evaluate the outcomes between Singapore and Osaka for OHCA patients with initial shockable rhythm using only population-based databases., Methods: This was a secondary analysis of two OHCA population-based databases in Osaka and Singapore, including adult OHCA patients with initial shockable rhythm. A machine-learning-based prediction model was derived from the Osaka data (n = 3088) and applied to the PAROS-SG data (n = 2905). We calculated the observed-expected ratio (OE ratio) for good neurological outcomes observed in Singapore and the expected derived from the data in Osaka by dividing subgroups with or without prehospital ROSC., Results: The one-month good neurological outcomes in Osaka and Singapore among patients with prehospital ROSC were 70% (791/1,125) and 57% (440/773), and among patients without prehospital ROSC were 10% (196/1963) and 2.8% (60/2,132). After adjusting patient characteristics, the outcome in Singapore was slightly better than expected from Osaka in patients with ROSC (OE ratio, 1.067 [95%CI 1.012 to 1.125]), conversely, it was worse than expected in patients without prehospital ROSC (OE ratio, 0.238 [95%CI 0.173 to 0.294])., Conclusion: This study showed the outcomes of OHCA patients without prehospital ROSC in Singapore were worse than expected derived from Osaka data even using population-based databases. (249/250 words)., (© 2023. The Author(s).)

Background: Community first responders (CFRs) strengthen the Chain of Survival for out-of-hospital cardiac arrest (OHCA) care. Considerable efforts have been invested in Singapore's CFR program, during the years 2016-2020, by developing an app-based activation system called myResponder. This paper reports on national CFR response indicators to evaluate the real-world impact of these efforts., Methods: We matched data from the Singapore Civil Defence Force's CFR registry with the Pan Asian Resuscitation Outcomes Study (PAROS) registry data to calculate performance indicators. These included the number of CFRs receiving and accepting an issued alert per OHCA event. Also calculated were the fraction of OHCA events where CFRs received an issued alert, or accepted the alert, and arrived at the scene either before or after EMS. We also present trends of these indicators and compare the prevalence of these fractions between the CFR-attended and CFR-unattended OHCA events., Results: Of 6577 alerted OHCA events, 42.7% accepted an alert, 50% of these arrived at the scene and 71% of them arrived before EMS. Almost all CFR response indicators improved over time even for the pandemic year (2020). The fraction of OHCA events where >2 CFRs received an alert increased from 62% to 96%; the same figure for accepting an alert did not change much but >2 CFRs arriving at the scene increased from 0% to 7.5%. The fraction of OHCA events with an automated external defibrillator applied and defibrillation performed by CFR increased from 4.2% to 10.3% and 1.6% to 3%, respectively. Statistically significant differences were observed in these indicators when CFR-attended and CFR-unattended OHCA events were compared., Conclusion: This real-world study shows that activating CFRs using mobile technology can improve community response to OHCA and are bearing fruit in Singapore at a national level. Some targets for improvement and future research are highlighted in this report., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: MEH Ong reports grants from the Laerdal Foundation, Laerdal Medical, and Ramsey Social Justice Foundation for funding of the Pan-Asian Resuscitation Outcomes Study; an advisory relationship with Global Healthcare SG, a commercial entity that manufactures cooling devices. MEH Ong has a licensing agreement with ZOLL Medical Corporation and patent filed (Application no: 13/047,348) for a “Method of predicting acute cardiopulmonary events and survivability of a patient”. He is also the co-founder and scientific advisor of TIIM Healthcare, a commercial entity which develops real-time prediction and risk stratification solutions for triage. All other authors have no conflict of interest to declare., (© 2023 The Author(s).)

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., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Author(s).)

Background: Singapore and Osaka in Japan have comparable population sizes and prehospital management; however, the frequency of ECPR differs greatly for out-of-hospital cardiac arrest (OHCA) patients with initial shockable rhythm. Given this disparity, we hypothesized that the outcomes among the OHCA patients with initial shockable rhythm in Singapore were different from those in Osaka. The aim of this study was to evaluate the outcomes of OHCA patients with initial shockable rhythm in Singapore compared to the expected outcomes derived from Osaka data using machine learning-based prediction models., Methods: This was a secondary analysis of two OHCA databases: the Singapore PAROS database (SG-PAROS) and the Osaka-CRITICAL database from Osaka, Japan. This study included adult (18-74 years) OHCA patients with initial shockable rhythm. A machine learning-based prediction model was derived and validated using data from the Osaka-CRITICAL database (derivation data 2012-2017, validation data 2018-2019), and applied to the SG-PAROS database (2010-2016 data), to predict the risk-adjusted probability of favorable neurological outcomes. The observed and expected outcomes were compared using the observed-expected ratio (OE ratio) with 95% confidence intervals (CI)., Results: From the SG-PAROS database, 1,789 patients were included in the analysis. For OHCA patients who achieved return of spontaneous circulation (ROSC) on hospital arrival, the observed favorable neurological outcome was at the same level as expected (OE ratio: 0.905 [95%CI: 0.784-1.036]). On the other hand, for those who had continued cardiac arrest on hospital arrival, the outcomes were lower than expected (shockable rhythm on hospital arrival, OE ratio: 0.369 [95%CI: 0.258-0.499], and nonshockable rhythm, OE ratio: 0.137 [95%CI: 0.065-0.235])., Conclusion: This observational study found that the outcomes for patients with initial shockable rhythm but who did not obtain ROSC on hospital arrival in Singapore were lower than expected from Osaka. We hypothesize this is mainly due to differences in the use of ECPR., (© 2023. BioMed Central Ltd., part of Springer Nature.)

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., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Objectives: The relationship between the bystander witness type and receipt of bystander CPR (BCPR) is not well understood. Herein we compared BCPR administration between family and non-family witnessed out-of-hospital cardiac arrest (OHCA)., Background: In many communities, interventions in the past decade have contributed to an increased receipt of BCPR, for example in Singapore from 15% to 60%. However, BCPR rates have plateaued despite sustained and ongoing community-based interventions, which may be related to gaps in education or training for various witness types. The purpose of this study was to investigate the association between witness type and BCPR administration., Methods: Singapore data from 2010-2020 was extracted from the Pan-Asian Resuscitation Outcomes Study (PAROS) network registry (n = 25,024). All adult, layperson witnessed, non-traumatic OHCAs were included in this study., Results: Of 10,016 eligible OHCA cases, 6,895 were family witnessed and 3,121 were non-family witnessed. After adjustment for potential confounders, BCPR administration was less likely for non-family witnessed OHCA (OR 0.83, 95% CI 0.75, 0.93). After location stratification, non-family witnessed OHCAs were less likely to receive BCPR in residential settings (OR 0.75, 95% CI 0.66, 0.85). In non-residential settings, there was no statistically significant association between witness type and BCPR administration (OR 1.11, 95% CI 0.88, 1.39). Details regarding witness type and bystander CPR were limited., Conclusion: This study found differences in BCPR administration between family and non-family witnessed OHCA cases. Elucidation of witness characteristics may be useful to determine populations that would benefit most from CPR education and training., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: [Marcus EH Ong reports grants from the Laerdal Foundation, Laerdal Medical, and Ramsey Social Justice Foundation for funding of the Pan-Asian Resuscitation Outcomes Study; an advisory relationship with Global Healthcare SG, a commercial entity that manufactures cooling devices. Marcus EH Ong has a licensing agreement with ZOLL Medical Corporation and patent filed (Application no: 13/047,348) for a “Method of predicting acute cardiopulmonary events and survivability of a patient”. He is also the co-founder and scientific advisor of TIIM Healthcare, a commercial entity which develops real-time prediction and risk stratification solutions for triage. All other authors have no conflicts of interest to declare.], (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: The International Liaison Committee on Resuscitation (ILCOR) Research and Registries Working Group previously reported data on systems of care and outcomes of out-of-hospital cardiac arrest (OHCA) in 2015 from 16 national and regional registries. To describe the temporal trends with updated data on OHCA, we report the characteristics of OHCA from 2015 through 2017., Methods: We invited national and regional population-based OHCA registries for voluntary participation and included emergency medical services (EMS)-treated OHCA. We collected descriptive summary data of core elements of the latest Utstein style recommendation during 2016 and 2017 at each registry. For registries that participated in the previous 2015 report, we also extracted the 2015 data., Results: Eleven national registries in North America, Europe, Asia, and Oceania, and 4 regional registries in Europe were included in this report. Across registries, the estimated annual incidence of EMS-treated OHCA was 30.0-97.1 individuals per 100,000 population in 2015, 36.4-97.3 in 2016, and 40.8-100.2 in 2017. The provision of bystander cardiopulmonary resuscitation (CPR) varied from 37.2% to 79.0% in 2015, from 2.9% to 78.4% in 2016, and from 4.1% to 80.3% in 2017. Survival to hospital discharge or 30-day survival for EMS-treated OHCA ranged from 5.2% to 15.7% in 2015, from 6.2% to 15.8% in 2016, and from 4.6% to 16.4% in 2017., Conclusion: We observed an upward temporal trend in provision of bystander CPR in most registries. Although some registries showed favourable temporal trends in survival, less than half of registries in our study demonstrated such a trend., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Objective: Little is known about survival outcomes after traumatic cardiac arrest in Asia, or the association of Utstein factors with survival after traumatic cardiac arrests. This study aimed to describe the epidemiology and outcomes of traumatic cardiac arrests in Asia, and analyze Utstein factors associated with survival., Methods: Traumatic cardiac arrest patients from 13 countries in the Pan-Asian Resuscitation Outcomes Study registry from 2009 to 2018 were analyzed. Multilevel logistic regression was performed to identify factors associated with the primary outcomes of survival to hospital discharge and favorable neurological outcome (Cerebral Performance Category (CPC) 1-2), and the secondary outcome of return of spontaneous circulation (ROSC)., Results: There were 207,455 out-of-hospital cardiac arrest cases, of which 13,631 (6.6%) were trauma patients aged 18 years and above with resuscitation attempted and who had survival outcomes reported. The median age was 57 years (interquartile range 39-73), 23.0% received bystander cardiopulmonary resuscitation (CPR), 1750 (12.8%) had ROSC, 461 (3.4%) survived to discharge, and 131 (1.0%) had CPC 1-2. Factors associated with higher rates of survival to discharge and favorable neurological outcome were arrests witnessed by emergency medical services or private ambulances (survival to discharge adjusted odds ratio (aOR) = 2.95, 95% confidence interval (CI) = 1.99-4.38; CPC 1-2 aOR = 2.57, 95% CI = 1.25-5.27), bystander CPR (survival to discharge aOR = 2.16; 95% CI 1.71-2.72; CPC 1-2 aOR = 4.98, 95% CI = 3.27-7.57), and initial shockable rhythm (survival to discharge aOR = 12.00; 95% CI = 6.80-21.17; CPC 1-2 aOR = 33.28, 95% CI = 11.39-97.23) or initial pulseless electrical activity (survival to discharge aOR = 3.98; 95% CI = 2.99-5.30; CPC 1-2 aOR = 5.67, 95% CI = 3.05-10.53) relative to asystole., Conclusions: In traumatic cardiac arrest, early aggressive resuscitation may not be futile and bystander CPR may improve outcomes.

Objective: Understanding the social determinants of bystander cardiopulmonary resuscitation (CPR) receipt can inform the design of public health interventions to increase bystander CPR. The association of socioeconomic status with bystander CPR is generally poorly understood. We evaluated the relationship between socioeconomic status and bystander CPR in cases of out-of-hospital cardiac arrest (OHCA)., Methods: This was a retrospective cohort study based on the Singapore cohort of the Pan-Asian Resuscitation Outcomes Study registry between 2010 and 2018. We categorized patients into low, medium, and high Singapore Housing Index (SHI) levels-a building-level index of socioeconomic status. The primary outcome was receipt of bystander CPR. The secondary outcomes were prehospital return of spontaneous circulation and survival to discharge., Results: A total of 12,730 OHCA cases were included, the median age was 71 years, and 58.9% were male. The bystander CPR rate was 56.7%. Compared to patients in the low SHI category, those in the medium and high SHI categories were more likely to receive bystander CPR (medium SHI: adjusted odds ratio [aOR] 1.48, 95% CI 1.30-1.69; high SHI: aOR 1.93, 95% CI 1.67-2.24). High SHI patients had higher survival compared to low SHI patients on unadjusted analysis (OR 1.79, 95% CI 1.08-2.96), but not adjusted analysis (adjusted for age, sex, race, witness status, arrest time, past medical history of cancer, and first arrest rhythm). When comparing high with low SHI, females had larger increases in bystander CPR rates than males., Conclusions: Lower building-level socioeconomic status was independently associated with lower rate of bystander CPR, and females were more susceptible to the effect of low socioeconomic status on lower rate of bystander CPR.

Objective: Fewer out-of-hospital cardiac arrest (OHCA) patients received bystander cardiopulmonary resuscitation during the COVID-19 pandemic in Singapore. We investigated the impact of COVID-19 on barriers to dispatcher-assisted cardiopulmonary resuscitation (DA-CPR)., Methods: We reviewed audio recordings of all calls to our national ambulance service call centre during the pandemic (January-June 2020) and pre-pandemic (January-June 2019) periods. Our primary outcome was the presence of barriers to DA-CPR. Multivariable logistic regression was used to assess the effect of COVID-19 on the likelihood of barriers to and performance of DA-CPR, adjusting for patient and event characteristics., Results: There were 1241 and 1118 OHCA who were eligible for DA-CPR during the pandemic (median age 74 years, 61.6 % males) and pre-pandemic (median age 73 years, 61.1 % males) periods, respectively. Compared to pre-pandemic, there were more residential and witnessed OHCA during the pandemic (87 % vs 84.9 % and 54 % vs 38.1 %, respectively); rates of DA-CPR were unchanged (57.3 % vs 61.1 %). COVID-19 increased the likelihood of barriers to DA-CPR (aOR 1.47, 95 % CI: 1.25-1.74) but not performance of DA-CPR (aOR 0.86, 95 % CI: 0.73 - 1.02). Barriers such as 'patient status changed' and 'caller not with patient' increased during COVID-19 pandemic. 'Afraid to do CPR' markedly decreased during the pandemic; fear of COVID-19 transmission made up 0.5 % of the barriers., Conclusion: Barriers to DA-CPR were encountered more frequently during the COVID-19 pandemic but did not affect callers' willingness to perform DA-CPR. Distancing measures led to more residential arrests with increases in certain barriers, highlighting opportunities for public education and intervention., Competing Interests: Declaration of Competing Interest SL Lim is supported by National University Health System Clinician Scientist Program; she has received research grants from National University Health System, National Kidney Foundation of Singapore and Singapore Heart Foundation. MEH Ong reports funding from the Zoll Medical Corporation for a study involving mechanical cardiopulmonary resuscitation devices; grants from the Laerdal Foundation, Laerdal Medical, and Ramsey Social Justice Foundation for funding of the Pan-Asian Resuscitation Outcomes Study; an advisory relationship with Global Healthcare SG, a commercial entity that manufactures cooling devices; and funding from Laerdal Medical on an observation program to their Community CPR Training Centre Research Program in Norway. MEH Ong has a licensing agreement and patent filed (Application no: 13/047,348) with ZOLL Medical Corporation for a study titled “Method of predicting acute cardiopulmonary events and survivability of a patient.” All other authors have no conflict of interest to disclose., (Copyright © 2022 The Author(s). Published by Elsevier B.V. All rights reserved.)

Variations in the impact of the COVID-19 pandemic on out-of-hospital cardiac arrest (OHCA) have been reported. We aimed to, using population-based registries, compare community response, Emergency Medical Services (EMS) interventions and outcomes of adult, EMS-treated, non-traumatic OHCA in Singapore and metropolitan Atlanta, before and during the pandemic. Associations of OHCA characteristics, pre-hospital interventions and pandemic with survival to hospital discharge were analyzed using logistic regression. There were 2084 cases during the pandemic (17 weeks from the first confirmed COVID-19 case) and 1900 in the pre-pandemic period (corresponding weeks in 2019). Compared to Atlanta, OHCAs in Singapore were older, received more bystander interventions (cardiopulmonary resuscitation (CPR): 65.0% vs. 41.4%; automated external defibrillator application: 28.6% vs. 10.1%), yet had lower survival (5.6% vs. 8.1%). Compared to the pre-pandemic period, OHCAs in Singapore and Atlanta occurred more at home (adjusted odds ratio (aOR) 2.05 and 2.03, respectively) and were transported less to hospitals (aOR 0.59 and 0.36, respectively) during the pandemic. Singapore reported more witnessed OHCAs (aOR 1.96) yet less bystander CPR (aOR 0.81) during pandemic, but not Atlanta (p < 0.05). The impact of COVID-19 on OHCA outcomes did not differ between cities. Changes in OHCA characteristics and management during the pandemic, and differences between Singapore and Atlanta were likely the result of systemic and sociocultural factors.

Aim of the Study: While out-of-hospital cardiac arrest (OHCA) is associated with poor survival, early bystander CPR (B-CPR) and telephone CPR (T-CPR) improves survival from OHCA. American Heart Association (AHA) Scientific Statements outline recommendations for T-CPR. We assessed these recommendations and hypothesized that meeting performance standards is associated with increased likelihood of survival. Additional variables were analyzed to identify future performance measurements., Methods: We conducted a retrospective cohort study of non-traumatic, adult, OHCA using the Singapore Pan-Asian Resuscitation Outcomes Study. The primary outcome was likelihood of survival; secondary outcomes were pre-hospital Return of Spontaneous Circulation (ROSC) and B-CPR., Results: From 2012 to 2016, 2,574 arrests met inclusion criteria. Mean age was 68 ± 15; of 2,574, 1,125 (44%) received T-CPR with 5% (135/2574) survival. T-CPR cases that met the Lerner et al. performance metrics analyzed, demonstrated no statistically significant association with survival. Cases which met the Kurz et al. criteria, "Time for Dispatch to Recognize Need for CPR" and "Time to First Compression," had adjusted odds ratios of survival of 1.01 (95% CI:1.00, 1.02; p = <0.01) and 0.99 (95% CI:0.99, 0.99; p = <0.01), respectively. Identified barriers to CPR decreased the odds of T-CPR and B-CPR being performed. Patients with prehospital ROSC had higher odds of B-CPR being performed. EMS response time < 8 minutes was associated with increased survival among patients receiving T-CPR., Conclusion: AHA scientific statements on T-CPR programs serve as ideal starting points for increasing the quality of T-CPR systems and patient outcomes. More work is needed to identify other system performance measures., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Introduction: Hospital-based resuscitation interventions, such as therapeutic temperature management (TTM), emergency percutaneous coronary intervention (PCI) and extracorporeal membrane oxygenation (ECMO) can improve outcomes in out-of-hospital cardiac arrest (OHCA). We investigated post-resuscitation interventions and hospital characteristics on OHCA outcomes across public hospitals in Singapore over a 9-year period., Methods: This was a prospective cohort study of all OHCA cases that presented to 6 hospitals in Singapore from 2010 to 2018. Data were extracted from the Pan-Asian Resuscitation Outcomes Study Clinical Research Network (PAROS CRN) registry. We excluded patients younger than 18 years or were dead on arrival at the emergency department. The outcomes were 30-day survival post-arrest, survival to admission, and neurological outcome., Results: The study analysed 17,735 cases. There was an increasing rate of provision of TTM, emergency PCI and ECMO ( P <0.001) in hospitals, and a positive trend of survival outcomes ( P <0.001). Relative to hospital F, hospitals B and C had lower provision rates of TTM (≤5.2%). ECMO rate was consistently <1% in all hospitals except hospital F. Hospitals A, B, C, E had <6.5% rates of provision of emergency PCI. Relative to hospital F, OHCA cases from hospitals A, B and C had lower odds of 30-day survival (adjusted odds ratio [aOR]<1; P <0.05 for hospitals A-C) and lower odds of good neurological outcomes (aOR<1; P <0.05 for hospitals A-C). OHCA cases from academic hospitals had higher odds ratio (OR) of 30-day survival (OR 1.3, 95% CI 1.1-1.5) than cases from hospitals without an academic status., Conclusion: Post-resuscitation interventions for OHCA increased across all hospitals in Singapore from 2010 to 2018, correlating with survival rates. The academic status of hospitals was associated with improved survival.

Objective: We aimed to examine the survival outcomes of out-of-hospital cardiac arrest (OHCA) patients, stratified by the transportation modes to the Emergency Department (ED)., Methods: This was a retrospective analysis of Singapore's Pan-Asian Resuscitation Outcomes Study registry from Apr 2010-Dec 2017. The primary outcome was survival to discharge or 30 days post-arrest. Secondary outcomes were the return of spontaneous circulation (ROSC) rate and neurological outcomes. A subgroup analysis was performed for OHCA cases who collapsed enroute., Results: A total of 15,376 cases were analysed. 15,129 (98.4%) were conveyed by Emergency Medical Services (EMS), 111 (0.72%) by private ambulance, 106 (0.69%) by own transport and 30 (0.2%) by public transport. 80% of patients brought by public transport arrested enroute, compared to 48.1% by own transport, 25.2% by private ambulance and 2.5% in the EMS group. 33/120 (27.5%) of paediatric OHCA cases were brought in by non-EMS transport to paediatric hospitals. The EMS group had the lowest survival rate at 4.5%, compared to 13.3% for public transport, 11.3% for own transport and 14.4% for private ambulance. ROSC rate was statistically significant but not for neurological outcomes. For the subgroup analysis, there was no statistical difference for primary and secondary outcomes across the groups., Conclusion: In Singapore, most OHCA patients are conveyed by EMS to the hospital, but some OHCA patients still arrive via alternative transport without prehospital interventions like bystander CPR. More can be done to educate the public to recognise an impending cardiac arrest and to activate EMS early for such cases., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background: Sudden cardiac arrest with or without sudden cardiac death (SCD) represents a heterogeneous spectrum of underlying etiology but is often a catastrophic event. Despite improvements in pre-hospital response and post-resuscitation care, outcomes remain grim. Thus, we aim to evaluate the predictors of survival in out-of-hospital cardiac arrests (OHCAs) and describe autopsy findings of those with the uncertain cause of death (COD)., Methods: This is a subgroup analysis of the Singapore cohort from the Pan Asian Resuscitation Outcome Study which studied 933 OHCAs admitted to two Singapore tertiary hospitals from April 2010 to May 2012., Results: Of the patients analysed, 30.2% ( n  = 282) had an initial return of spontaneous circulation (ROSC) at the emergency department, 18.0% ( n  = 168) had sustained ROSC with subsequent admission and 3.4% ( n  = 32) had survival to discharge. On multivariate analysis, an initial shockable rhythm, a witnessed event, prehospital defibrillation, and shorter time to hospital predicted ROSC as well as survival to discharge. A total of 163 (17.5%) autopsies were performed of which a cardiac etiology of SCD was noted in 92.1% ( n  = 151). Ischemic heart disease accounted for 54.3% ( n  = 89) of the autopsy cohort, with acute myocardial infarction (26.9%, n  = 44) and myocarditis (3.7%, n  = 6) rounding out the top three causes of demise., Conclusion: OHCA remains a clinical presentation that portends a poor prognosis. Of those with uncertain COD, cardiac etiology appears to predominate from autopsy study. Identification of prognostic factors will play an important role in improving individual-level and systemic-level variables to further optimize outcomes., Competing Interests: MEH Ong reports funding from the Zoll Medical Corporation for a study involving mechanical cardiopulmonary resuscitation devices; grants from the Laerdal Foundation, Laerdal Medical, and Ramsey Social Justice Foundation for funding of the Pan‐Asian Resuscitation Outcomes Study; an advisory relationship with Global Healthcare SG, a commercial entity that manufactures cooling devices; and funding from Laerdal Medical on an observation program to their Community CPR Training Centre Research Program in Norway. MEH Ong has a licensing agreement and a patent filed (Application no: 13/047,348) with ZOLL Medical Corporation for a study titled “Method of predicting acute cardiopulmonary events and survivability of a patient.” All other authors have no conflict of interest to disclose., (© 2022 The Authors. Journal of Arrhythmia published by John Wiley & Sons Australia, Ltd on behalf of the Japanese Heart Rhythm Society.)

Background: Current Advanced Life Support Termination of Resuscitation (TOR) guidelines suggest when to cease cardiopulmonary resuscitation (CPR). With the significant increase of Dispatch-Assisted CPR (DA-CPR) programs, the impact of DA-CPR on the TOR criteria performance is not clear., Methods: We conducted a secondary analysis of a prospectively collected registry, the Pan-Asian Resuscitation Outcomes Study. We included patients >15 years old with out-of-hospital cardiac arrest between 2014 and 2017 (after implementation of Singapore's DA-CPR program). We excluded patients with non-cardiac etiology, known do-not-resuscitate status, and healthcare provider bystanders. All cases were collected in accordance to Utstein standards. We evaluated the addition of DA-CPR to the diagnostic performance of TOR criteria using logistic regression modeling. The primary outcome was performance for predicting non-survival at 30 days. Sensitivity, specificity, and positive and negative predictive values were calculated., Results: Of the 6009 cases, 319 (5.3%) were still alive at 30 days. Patients had a mean age of 67.9 (standard deviation 15.7) years and were mostly male and Chinese. Almost half of patients had no bystander CPR. The TOR criteria differentiating DA-CPR from unassisted bystander CPR has a specificity of 94% and predictive value of death of 99%, which was not significantly different from undifferentiated CPR criteria. There were differences in adjusted association with survival between unassisted and DA-CPR., Conclusion: Advanced life support TOR criteria retain high specificity and predictive value of death in the context of DA-CPR. Further research should explore the differences between unassisted CPR and DA-CPR to understand differential survival outcomes., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Aim: Dispatcher-assisted cardiopulmonary resuscitation (DA-CPR) can increase bystander CPR rates and improve outcomes in out-of-hospital cardiac arrest (OHCA). Despite the use of protocols, dispatchers may falsely recognise some cases to be in cardiac arrest. Hence, this study aimed to find the incidence of DA-CPR initiated for non-OHCA cases, its characteristics and clinical outcomes in the Singapore population., Methods: This was a multi-centre, observational study of all dispatcher-recognised cardiac arrests cases between January to December 2017 involving three tertiary hospitals in Singapore. Data was obtained from the Pan-Asian Resuscitation Outcomes Study cohort. Audio review of dispatch calls from the national emergency ambulance service were conducted and information about patients' clinical outcomes were prospectively collected from health records. Univariate analysis was performed to determine factors associated with in-hospital mortality among non-OHCA patients who received DA-CPR., Results: Of the 821 patients recognised as having OHCA 328 (40.0%) were not in cardiac arrest and 173 (52.7%) of these received DA-CPR. No complications from chest compressions were found from hospital records. The top diagnoses of non-OHCA patients were cerebrovascular accidents (CVA), syncope and infection. Only final diagnoses of CVA (aOR 20.68), infection (aOR 17.34) and myocardial infarction (aOR 32.19) were significantly associated with in-hospital mortality., Conclusion: In this study, chest compressions initiated on patients not in cardiac arrest by dispatchers did not result in any reported complications and was not associated with in-hospital mortality. This provides reassurance for the continued implementation of DA-CPR., (Copyright © 2021 Elsevier B.V. All rights reserved.)

We evaluated the association between early coronary angiography (CAG) and outcomes in resuscitated out-of-hospital cardiac arrest (OHCA) patients, by linking data from the Singapore Pan-Asian Resuscitation Outcomes Study, with a national registry of cardiac procedures. The 30-day survival and neurological outcome were compared between patients undergoing early CAG (within 1-calender day), versus patients not undergoing early CAG. Inverse probability weighted estimates (IPWE) adjusted for non-randomized CAG. Of 976 resuscitated OHCA patients of cardiac etiology between 2011-2015 (mean(SD) age 64(13) years, 73.7% males), 337 (34.5%) underwent early CAG, of whom, 230 (68.2%) underwent PCI. Those who underwent early CAG were significantly younger (60(12) vs. 66(14) years old), healthier (42% vs. 59% with heart disease; 29% vs. 44% with diabetes), more likely males (86% vs. 67%), and presented with shockable rhythms (69% vs. 36%), compared with those who did not. Early CAG with PCI was associated with better survival and neurological outcome (adjusted odds ratio 1.91 and 1.82 respectively), findings robust to IPWE adjustment. The rates of bleeding and stroke were similar. CAG with PCI within 24 h was associated with improved clinical outcomes after OHCA, without increasing complications. Further studies are required to identify the characteristics of patients who would benefit most from this invasive strategy.

Objective: Out-of-hospital cardiac arrest (OHCA) is associated with poor survival. Studies have demonstrated improved survival with early bystander cardiopulmonary resuscitation (BCPR). This study evaluated the impact of a dispatcher-assisted CPR (DA-CPR) program on BCPR rate and outcomes of OHCA in a developing emergency medical services (EMS) system setting., Methods: Data were extracted from the national cardiac arrest registry. A before-after analysis was performed between OHCA cases with cardiac etiology conveyed by EMS from April 2010-June 2012 (pre-intervention) and July 2012-December 2015 (post-intervention). Primary outcomes were survival-to-discharge/30 days post-arrest and favorable cerebral performance (Glasgow-Pittsburgh cerebral performance categories 1 and 2)., Results: 6365 OHCA cases were analyzed with 2129 in the pre-intervention and 4236 in the post-intervention group. In the post-intervention group, there was an increase in BCPR rates from 24.8% to 53.8% (p < 0.001), adjusted OR 3.67 (aOR; 95%CI: 3.26-4.13). OHCA outcomes also improved with survival-to-discharge rates increasing from 3.0%-4.5% (p < 0.01), aOR 2.10 (95%CI: 1.40-3.17) and favorable cerebral performance increasing from 1.6% to 2.7% (p < 0.05), aOR 2.82 (95%CI: 1.65-4.82). In patients with initial shockable rhythm, BCPR without dispatcher assistance was associated with significantly higher odds of survival-to-discharge (aOR 1.67, 95%CI: 1.06-2.64) and favorable cerebral performance (aOR 2.32, 95%CI: 1.26-4.27) compared to no BCPR., Conclusion: Our study showed that a simplified DA-CPR program can be successfully implemented in a developing EMS system and can contribute to higher BCPR rate and in turn, improve OHCA survival. Future studies can examine bystanders' characteristics and quality of the CPR performed to understand their impact on survival.

Background: Organ donation after brain death is the standard practice in many countries. Rates are low globally. This study explores the potential national number of candidates for uncontrolled donations after cardiac death (uDCD) amongst out-of-hospital cardiac arrest (OHCA) patients and the influence of extracorporeal cardiopulmonary resuscitation (ECPR) on the candidacy of these potential organ donors using Singapore as a case study., Methods: Using Singapore data from the Pan-Asian Resuscitation Outcomes Study, we identified all non-traumatic OHCA cases from 2010 to 2016. Four established criteria for identifying uDCD candidates (Madrid, San Carlos Madrid, Maastricht and Paris) were retrospectively applied onto the population. Within these four groups, a condensed ECPR eligibility criteria was employed and thereafter, an estimated ECPR survival rate was applied, extrapolating for possible neurologically intact survivors had ECPR been administered., Results: 12,546 OHCA cases (64.8% male, mean age 65.2 years old) qualified for analysis. The estimated number of OHCA patients who were eligible for uDCD ranged from 4.3 to 19.6%. The final projected percentage of potential uDCD donors readjusted for ECPR survivors was 4.2% (Paris criteria worst-case scenario, n = 532) to 19.4% of all OHCA cases (Maastricht criteria best-case scenario, n = 2428), for an estimated 14.3 to 65.4 uDCD donors per million population per year (pmp/year)., Conclusions: In Singapore case study, we demonstrated the potential numbers of candidates for uDCD among resuscitated OHCA cases. This sizeable pool of potential donors demonstrates the potential for an uDCD program to expand the organ donor pool. A small proportion of these patients might however survive had they been administered ECPR. Further research into the factors influencing local organ and patient outcomes following uDCD and ECPR is indicated., (© 2021. The Author(s).)

Objective: The Singapore myResponder is a novel smartphone application developed by the Singapore Civil Defence Force (SCDF) that notifies volunteer first responders of a suspected out-of-hospital cardiac arrest (OHCA) case and locations of Automated External Defibrillators (AED) in the vicinity so that they can assist with resuscitation. We aimed to examine the performance of this application, challenges encountered, and future directions. Methods: We analyzed data from the myResponder app since its launch from April 2015 to July 2019. The number of installations, registered community first responders, suspected OHCA cases, notifications sent by the app, percentage of responders who accepted activation and arrived at scene were reviewed. A subgroup of taxi driving responders (within a 1.5-kilometer response radius) carrying an AED under a subsequent pilot program was also analyzed. Results: By July 2019, 46,689 responders were registered in the myResponder app. There were a total of 19,189 cases created for suspected OHCA, with a median of 358 cases per month (IQR 330-430), in which 10,073 responders accepted activation from myResponder and 4,955 arrived on-scene. A total of 135,599 notifications were sent for these cases, with a median of 7.1 notifications per case (IQR 4.3-8.7). In 2019, the percentages of responders who accepted notification and arrived on scene were 45.8% and 24.1%, respectively. 43% (1110/2581) of responders arrived before EMS crew. Conclusion: The myResponder mobile application is a feasible smart technology solution to improve community response to OHCA, and to increase bystander CPR and AED use. Future directions include increasing the number of active responders, improving response rates, app performance, and better data capture for quality improvement.

This study aimed to evaluate the impact of the Coronavirus Disease 2019 (COVID-19) pandemic on out-of-hospital cardiac arrest (OHCA) in Singapore. We used data from the Singapore Civil Defence Force to compare the incidence, characteristics and outcomes of all Emergency Medical Services (EMS)-attended adult OHCA during the pandemic (January-May 2020) and pre-pandemic (January-May 2018 and 2019) periods. Pre-hospital return of spontaneous circulation (ROSC) was the primary outcome. Binary logistic regression was used to calculate the adjusted odds ratios (aOR) for the characteristics of OHCA. Of the 3893 OHCA patients (median age 72 years, 63.7% males), 1400 occurred during the pandemic period and 2493 during the pre-pandemic period. Compared with the pre-pandemic period, OHCAs during the pandemic period more likely occurred at home (aOR: 1.48; 95% CI: 1.24-1.75) and were witnessed (aOR: 1.71; 95% CI: 1.49-1.97). They received less bystander CPR (aOR: 0.70; 95% CI: 0.61-0.81) despite 65% of witnessed arrests by a family member, and waited longer for EMS (OR ≥ 10 min: 1.71, 95% CI 1.46-2.00). Pre-hospital ROSC was less likely during the pandemic period (aOR: 0.67; 95% CI: 0.53-0.84). The pandemic saw increased OHCA incidence and worse outcomes in Singapore, likely indirect effects of COVID-19.

Background: Out-of-hospital cardiac arrests with negligible chance of survival are routinely transported to hospital and many are pronounced dead thereafter. This leads to some potentially avoidable costs. The 'Termination of Resuscitation' protocol allows paramedics to terminate resuscitation efforts onsite for medically futile cases. This study estimates the changes in frequency of costly events that might occur when the protocol is applied to out-of-hospital cardiac arrests, as compared to existing practice., Methods: We used Singapore data from the Pan-Asian Resuscitation Outcomes Study, from 1 Jan 2014 to 31 Dec 2017. A Markov model was developed to summarise the events that would occur in two scenarios, existing practice and the implementation of a Termination of Resuscitation protocol. The model was evaluated for 10,000 hypothetical patients with a cycle duration of 30 days after having a cardiac arrest. Probabilistic sensitivity analysis accounted for uncertainties in the outcomes: number of urgent transports and emergency treatments, inpatient bed days, and total number of deaths., Results: For every 10,000 patients, existing practice resulted in 1118 (95% Uncertainty Interval 1117 to 1119) additional urgent transports to hospital and subsequent emergency treatments. There were 93 (95% Uncertainty Interval 66 to 120) extra inpatient bed days used, and 3 fewer deaths (95% Uncertainty Interval 2 to 4) in comparison to using the protocol., Conclusion: The findings provide some evidence for adopting the Termination of Resuscitation protocol. This policy could lead to a reduction in costs and non-beneficial hospital admissions, however there may be a small increase in the number of avoidable deaths., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.The authors report no declarations of interest., (© 2021 The Author(s).)

Introduction: Bystander cardiopulmonary resuscitation (B-CPR) is associated with improved out-of hospital cardiac arrest survival. Community-level interventions including dispatcher-assisted CPR (DA-CPR) and myResponder were implemented to increase B-CPR. We sought to assess whether these interventions increased B-CPR., Methods: The Singapore out-of-hospital cardiac arrest registry captured cases that occurred between 2010 and 2017. Outcomes occurring in 3 time periods (Baseline, DA-CPR, and DA-CPR plus myResponder) were compared. Segmented regression of time-series data was conducted to investigate our intervention impact on the temporal changes in B-CPR., Results: A total of 13,829 out-of-hospital cardiac arrest cases were included from April 2010 to December 2017. Higher B-CPR rates (24.8% versus 50.8% vs 64.4%) were observed across the 3 time periods. B-CPR rates showed an increasing but plateauing trend. DA-CPR implementation was significantly associated with an increased B-CPR (level odds ratio [OR] 2.26, 95% confidence interval [CI] 1.79-2.88; trend OR 1.03, 95% CI 1.01-1.04), while no positive change was detected with myResponder (level OR 0.95, 95% CI 0.82-1.11; trend OR 0.99, 95% CI 0.98-1.00)., Conclusion: B-CPR rates in Singapore have been increasing alongside the implementation of community-level interventions such as DA-CPR and myResponder. DA-CPR was associated with improved odds of receiving B-CPR over time while the impact of myResponder was less clear.

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.

Background: Bystander cardiopulmonary resuscitation (CPR) increases an individual's chance of survival from out-of-hospital cardiac arrest (OHCA), but the frequency of bystander CPR is low in many communities. We aimed to assess the cumulative effect of CPR-targeted public health interventions in Singapore, which were incrementally introduced between 2012 and 2016., Methods: We did a secondary analysis of a prospective cohort study of adult, non-traumatic OHCAs, through the Singapore registry. National interventions introduced during this time included emergency services interventions, as well as dispatch-assisted CPR (introduced on July 1, 2012), a training programme for CPR and automated external defibrillators (April 1, 2014), and a first responder mobile application (myResponder; April 17, 2015). Using multilevel mixed-effects logistic regression, we modelled the likelihood of receiving bystander CPR with the increasing number of interventions, accounting for year as a random effect., Findings: The Singapore registry contained 11 465 OHCA events between Jan 1, 2011, and Dec 31, 2016. Paediatric arrests, arrests witnessed by emergency medical services, and healthcare-facility arrests were excluded, and 6788 events were analysed. Bystander CPR was administered in 3248 (48%) of 6788 events. Compared with no intervention, likelihood of bystander CPR was not significantly altered by the addition of emergency medical services interventions (odds ratio [OR] 1·33 [95% CI 0·98-1·79]; p=0·065), but increased with implementation of dispatch-assisted CPR (3·72 [2·84-4·88]; p<0·0001), with addition of the CPR and automated external defibrillator training programme (6·16 [4·66-8·14]; p<0·0001), and with addition of the myResponder application (7·66 [5·85-10·03]; p<0·0001). Survival to hospital discharge increased after the addition of all interventions, compared with no intervention (OR 3·10 [95% CI 1·53-6·26]; p<0·0001)., Interpretation: National bystander-focused public health interventions were associated with an increased likelihood of bystander CPR, and an increased survival to hospital discharge. Understanding the combined impact of public health interventions might improve strategies to increase the likelihood of bystander CPR, and inform targeted initiatives to improve survival from OHCA., Funding: National Medical Research Council, Clinician Scientist Award, Singapore and Ministry of Health, Health Services Research Grant, Singapore., (Copyright © 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Background: Since development of the Utstein style recommendations for the uniform reporting of cardiac arrest, increasing numbers of national and regional out-of-hospital cardiac arrest (OHCA) registries have been established worldwide. The International Liaison Committee on Resuscitation (ILCOR) created the Research and Registries Working Group and aimed to systematically report data collected from these registries., Methods: We conducted two surveys of voluntarily participating national and regional registries. The first survey aimed to identify which core elements of the current Utstein style for OHCA were collected by each registry. The second survey collected descriptive summary data from each registry. We chose the data collected for the second survey based on the availability of core elements identified by the first survey., Results: Seven national and four regional registries were included in the first survey and nine national and seven regional registries in the second survey. The estimated annual incidence of emergency medical services (EMS)-treated OHCA was 30.0-97.1 individuals per 100,000 population. The combined data showed the median age varied from 64 to 79 years and more than half were male in all 16 registries. The provision of bystander cardiopulmonary resuscitation (CPR) and bystander automated external defibrillator (AED) use was 19.1-79.0% in all registries and 2.0-37.4% among 11 registries, respectively. Survival to hospital discharge or 30-day survival after EMS-treated OHCA was 3.1-20.4% across all registries. Favorable neurological outcome at hospital discharge or 30 days after EMS-treated OHCA was 2.8-18.2%. Survival to hospital discharge or 30-day survival after bystander-witnessed shockable OHCA ranged from 11.7% to 47.4% and favorable neurological outcome from 9.9% to 33.3%., Conclusion: This report from ILCOR describes data on systems of care and outcomes following OHCA from nine national and seven regional registries across the world. We found variation in reported survival outcomes and other core elements of the current Utstein style recommendations for OHCA across nations and regions., (Copyright © 2020. Published by Elsevier B.V.)

Aims: Singapore is highly-urbanized, with >90% of the population living in high-rise apartments. She has implemented several city-wide interventions such as dispatcher-assisted CPR, community CPR training and smartphone activation of volunteers to increase bystander CPR (BCPR) rates for out-of-hospital cardiac arrest (OHCA). These may have different impact on residential and non-residential OHCA. We aimed to evaluate the characteristics, processes-of-care and outcome differences between residential and non-residential OHCA and study the differences in temporal trends of BCPR rates., Methods: This was a national, observational study in Singapore from 2010 to 2016, using data from the prospective Pan-Asian Resuscitation Outcomes Study. The primary outcome was survival (to-discharge or to-30-days). Multivariate logistic regression was performed to determine the effect of location-type on survival and a test of statistical interaction was performed to assess the difference in the temporal relationship of BCPR rates between location-type., Results: 8397 cases qualified for analysis, of which 5990 (71.3%) were residential. BCPR and bystander automated external defibrillator (AED) rates were significantly lower in residential as compared to non-residential arrests (41.0% vs 53.6%, p < 0.01; 0.4% vs 10.8%, p < 0.01 respectively). Residential BCPR increased from 15.8% (2010) to 57.1% (2016). Residential cardiac arrests had lower survival-to-discharge (2.9% vs 10.1%, p < 0.01). Multivariate logistic regression analysis showed that location-type had an independent effect on survival, with residential arrests having poorer survival compared to non-residential cardiac arrests (adjusted OR 0.547 [0.435-0.688]). A test of statistical interaction showed a significant interaction effect between year and location-type for bystander CPR, with a narrowing of differences in bystander CPR between residential and non-residential cardiac arrests over the years., Conclusion: Residential cardiac arrests had poorer bystander intervention and survival from 2010 to 2016 in Singapore. BCPR had improved more in residential arrests compared to non-residential arrests over a period of city-wide interventions to improve BCPR., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Introduction: Nursing home (NH) residents with out-of-hospital cardiac arrests (OHCA) have unique resuscitation priorities. This study aimed to describe OHCA characteristics in NH residents and identify independent predictors of survival., Materials and Methods: OHCA cases between 2010-16 in the Pan-Asian Resuscitation Outcomes Study were retrospectively analysed. Patients aged <18 years old and non-emergency cases were excluded. Primary outcome was survival at discharge or 30 days. Good neurological outcome was defined as a cerebral performance score between 1-2., Results: A total of 12,112 cases were included. Of these, 449 (3.7%) were NH residents who were older (median age 79 years, range 69-87 years) and more likely to have a history of stroke, heart and respiratory diseases. Fewer NH OHCA had presumed cardiac aetiology (62% vs 70%, P <0.01) and initial shockable rhythm (8.9% vs 18%, P <0.01), but had higher incidence of bystander cardiopulmonary resuscitation (74% vs 43%, P <0.01) and defibrillator use (8.5% vs 2.8%, P <0.01). Non-NH (2.8%) residents had better neurological outcomes than NH (0.9%) residents ( P <0.05). Factors associated with survival for cardiac aetiology included age <65 years old, witnessed arrest, bystander defibrillator use and initial shockable rhythm; for non-cardiac aetiology, these included witnessed arrest (adjusted odds ratio [AOR] 3.8, P <0.001) and initial shockable rhythm (AOR 5.7, P <0.001)., Conclusion: Neurological outcomes were poorer in NH survivors of OHCA. These findings should inform health policies on termination of resuscitation, advance care directives and do-not-resuscitate orders in this population.

Introduction: The use of targeted temperature management (TTM) is increasing although adoption is still variable. We describe our 6-year experience and compare the mortality and neurological outcomes of out-of-hospital cardiac arrest (OHCA) patients with and without the use of TTM in a multiethnic Asian population., Materials and Methods: We performed a retrospective observational study at a tertiary academic medical centre. OHCA survivors admitted to our hospital between April 2010‒December 2016 were included. Outcomes of interest were 30-day mortality postresuscitation, Cerebral Performance Category (CPC) and Overall Performance Category (OPC) scores., Results: A total of 121 of 261 patients (46.3%) underwent TTM. TTM patients were younger (TTM 60.0 years old vs no TTM 63.7 years old, P = 0.047). There was no difference in the initial arrest rhythm of shockable origin between the 2 groups ( P = 0.289). There was suggestion of lower 30-day mortality (TTM 24.3% vs no TTM 31.4%, P = 0.214), higher and good CPC/OPC scores (TTM 19.0% vs no TTM 15.7%, P = 0.514) with TTM although this did not reach statistical significance. On multivariable logistic regression analysis, TTM was not associated with 30-day mortality ( P = 0.07). However, older age, initial non-shockable rhythm and increased duration from arrest to return of spontaneous circulation were associated with increased mortality. Malay ethnicity was associated with a poorer CPC/ OPC score., Conclusion: Adoption and outcomes of TTM postresuscitation is variable and there is still a need to optimise management of the identified predictors of survival and good neurological outcomes while TTM is being used.

Objective: We aimed to examine the association of ethnicity and socioeconomic status (SES) with Out-of-Hospital Cardiac Arrest (OHCA) incidence and 30-day survival in Singapore. Methods: We analyzed the Singapore cohort of Pan-Asia Resuscitation Outcome Study (PAROS), a multi-center, prospective OHCA registry between 2010 and 2015. The Singapore Socioeconomic Disadvantage Index (SEDI) score, obtained according to zip code, was used as surrogate for neighborhood SES. Age-adjusted OHCA incidence and Utstein survival were calculated by ethnicity and SES. Utstein survival was defined as the number of cardiac OHCA cases with initial rhythm of ventricular fibrillation witnessed by a bystander who survived 30-days or until hospital discharge. Logistic regression was used to investigate association of ethnicity with 30-day and Utstein survivals. Results: Our study population comprised 8,900 patients: 6,453 Chinese, 1,472 Malays, and 975 Indians. The overall age-adjusted incidence ratios (95% CI) for Malay/Chinese and Indian/Chinese were 1.93 (1.83-2.04) and 1.95 (1.83-2.08), respectively. The overall age-adjusted incidence ratios (95% CI) for average/low and high/low SEDI group were 1.12 (0.95-1.33) and 1.29 (1.08-1.53), respectively. Malay showed lesser Utstein survival of 8.1% compared to Chinese (14.6%) and Indian (20.4%) [p = 0.018]. Ethnicity did not reach statistical significance (p = 0.072) in forward selection model of Utstein survival, while SEDI score and category were not significant (p > 0.2 and p = 0.349). Conclusions: We found Malay and Indian communities to be at higher risks of OHCA compared to Chinese, and additionally, the Malay community is at higher risk of subsequent mortality than the Chinese and Indian communities. These disparities were not explained by neighborhood SES.

Background: A large proportion of out-of-hospital cardiac arrest (OHCA) cases occur in high-rise residential buildings. This study aims to investigate the effect of vertical location on survival outcomes and response times., Methods: This is a retrospective study based on data obtained from the Singapore cohort of the Pan-Asian Resuscitation Outcomes Study (PAROS) from January 2011 to December 2014. Study subjects were OHCA cases, unwitnessed and transported by EMS personnel, with known vertical location (floor) data. Traumatic arrests with no resuscitation attempted and missing vertical locations were excluded. The primary outcome was survival to hospital discharge or 30 days post-cardiac arrest., Results: A total of 5678 OHCA cases were included in the study. The effect of floors on survival was manifested as a U-shaped response. Survival rates of 4.5% for the 4 pooled basement floors and 6.2% for the ground floor (floor 1) were contrasted by a substantial drop to 2.7% at floor 2 and continuing decline to 0.7% at floor 6. In a multivariable model using stepwise logistic regression, both linear (p = 0.0285) and quadratic (p = 0.0018) floor effects remained significant after adjustment for other significant risk factors, age, bystander witnessed arrest, first arrest rhythm, ROSC on scene/enroute, and EMS response times. Harrell's C-statistic for a predictive model incorporating these variables was 0.933., Conclusions: Vertical location is associated with OHCA survival probability with a U-shaped response, and this significance remained after adjustment for other significant OHCA variables. This relationship is likely multifactorial and more research is needed to elucidate the various factors., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Studies are divided on the effect of day-night temporal differences on clinical outcomes in out-of-hospital cardiac arrest (OHCA). This study aimed to elucidate any differences in OHCA survival between day and night occurrence, and the factors associated with differences in survival.This was a prospective, observational study of OHCA cases across multinational Pan-Asian sites. Cases were divided according to time call received by dispatch centers into day (0700H-1900H) and night (1900H-0659H). Primary outcome was 30-day survival. Secondary outcomes were prehospital and hospital modifiable resuscitative characteristics.About 22,501 out of 55,881 cases occurred at night. Night cases were less likely to be witnessed (40.2% vs. 43.1%, P < .001), more likely to occur at home (32.5% vs. 29%, P < .001), had non-shockable initial rhythms (90.8% vs. 89.4%, P < .001), lower bystander CPR rates (36.2 vs. 37.6%, P = .001), lower bystander AED application rate (0.3% vs. 0.7%, P < .001), lower rates of prehospital defibrillation (13% vs. 14.4%, P < .001), and were less likely to receive prehospital adrenaline (9.8% vs. 11%, P < .001). 30-day survival at night was lower with an adjusted odds ratio of 0.79 (95% CI 0.73-0.86, P < .001). On multivariate logistic regression, occurrence at night was associated with decreased provision of bystander CPR, bystander AED application, and prehospital adrenaline.30-day survival was worse in OHCA occurring at night. There were circadian patterns in incidence. Bystander CPR and bystander AED application were significantly lower at night in multivariate analysis. This would at least partially explain the decreased survival at night.