Cardiopulmonary resuscitation outcome of out-of-hospital cardiac arrest in low-volume versus high-volume emergency departments: An observational study and propensity score matching analysis

Development of Prediction Models for Acute Myocardial Infarction at Prehospital Stage with Machine Learning Based on a Nationwide Database

Models for predicting acute myocardial infarction (AMI) at the prehospital stage were developed and their efficacy compared, based on variables identified from a nationwide systematic emergency medical service (EMS) registry using conventional statistical methods and machine learning algorithms. Patients in the EMS cardiovascular registry aged >15 years who were transferred from the public EMS to emergency departments in Korea from January 2016 to December 2018 were enrolled. Two datasets were constructed according to the hierarchical structure of the registry. A total of 184,577 patients (Dataset 1) were included in the final analysis. Among them, 72,439 patients (Dataset 2) were suspected to have AMI at prehospital stage. Between the models derived using the conventional logistic regression method, the B-type model incorporated AMI-specific variables from the A-type model and exhibited a superior discriminative ability (p = 0.02). The models that used extreme gradient boosting and a multilayer perceptron yielded a higher predictive performance than the conventional logistic regression-based models for analyses that used both datasets. Each machine learning algorithm yielded different classification lists of the 10 most important features. Therefore, prediction models that use nationwide prehospital data and are developed with appropriate structures can improve the identification of patients who require timely AMI management.

Effect of annual hospital admissions of out-of-hospital cardiac arrest patients on prognosis following cardiac arrest

Background

Although the prognosis of patients treated at specialized facilities has improved, the relationship between the number of patients treated at hospitals and prognosis is controversial and lacks constancy in those with out-of-hospital cardiac arrest (OHCA). This study aimed to clarify the effect of annual hospital admissions on the prognosis of adult patients with OHCA by analyzing a large cohort.

Methods

The effect of annual hospital admissions on patient prognosis was analyzed retrospectively using data from the Japanese Association for Acute Medicine OHCA registry, a nationwide multihospital prospective database. This study analyzed 3632 of 35,754 patients hospitalized for OHCA of cardiac origin at 86 hospitals. The hospitals were divided into tertiles based on the volume of annual admissions. The effect of hospital volume on prognosis was analyzed using logistic regression analysis with multiple imputation. Furthermore, three subgroup analyses were performed for patients with return of spontaneous circulation (ROSC) before arrival at the emergency department, patients admitted to critical care medical centers, and patients admitted to extracorporeal membrane oxygenation-capable hospitals.

Results

Favorable neurological outcomes 30 days after OHCA for patients overall showed no advantage for medium- and high-volume centers over low-volume centers; Odds ratio (OR) 0.989, (95% Confidence interval [CI] 0.562-1.741), OR 1.504 (95% CI 0.919-2.463), respectively. However, the frequency of favorable neurological outcomes in OHCA patients with ROSC before arrival at the emergency department at high-volume centers was higher than those at low-volume centers (OR 1.955, 95% CI 1.033-3.851).

Conclusion

Hospital volume did not significantly affect the prognosis of adult patients with OHCA. However, transport to a high-volume hospital may improve the neurological prognosis in OHCA patients with ROSC before arrival at the emergency department.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12873-022-00685-7.

Gender effect in survival after out-of-hospital cardiac arrest: A nationwide, population-based, case-control propensity score matched study based Korean national cardiac arrest registry

Objective

This study aimed to describe the relationship between sex and survival of patients with out-of-hospital cardiac arrest (OHCA) and further investigate the potential impact of female reproductive hormones on survival outcomes, by stratifying the patients into two age groups.

Methods

This retrospective, national population-based observational, case-control study, included Korean OHCA data from January 1, 2009, to December 31, 2016. We used multiple logistic regression with propensity score-matched data. The primary outcome was survival-to-discharge.

Results

Of the 94,160 patients with OHCA included, 34.2% were women. Before propensity score matching (PSM), the survival-to-discharge rate was 5.2% for females and 9.1% for males, in the entire group (OR 0.556, 95% CI [–0.526–0.588], P<0.001). In the reproductive age group (age 18–44 years), the survival-to-discharge rate was 14% for females and 15.6% for males (OR 0.879, 95% CI [0.765–1.012], P = 0,072) and in the post-menopause age group (age ≥ 55 years), the survival-to-discharge rate was 4.1% for females and 7% for males (OR 0.562, 95% CI [0.524–0.603], P<0.001). After PSM (28,577 patients of each sex), the survival-to-discharge rate was 5.4% for females and 5.4% for males (OR, 1.009 [0.938–1.085], P = 0.810). In the reproductive age group, the survival-to-discharge rate was 14.5% for females and 11.5% for males (OR 1.306, 95% CI [1.079–1.580], P = 0.006) and in the post-menopause age group, the survival-to-discharge rate was 4.2% for females and 4.6% for males (OR 0.904, 95% CI [0.828–0.986], P = 0.022). After adjustment for confounders, women of reproductive age were more likely to survive at hospital discharge. However, there was no statistically significant difference in neurological outcome (OR 1.238, 95% CI [0.979–1.566], P = 0.074).

Conclusions

Females of reproductive age had a better chance of survival when matched for confounding factors. Further studies using sex hormones are needed to improve the survival rate of patients with OHCA.

Association of High-Volume Centers With Survival Outcomes Among Patients With Nontraumatic Out-of-Hospital Cardiac Arrest: A Systematic Review and Meta-Analysis

Importance

Although high volume of cases of out-of-hospital cardiac arrest (OHCA) is a key feature of cardiac arrest centers, which have proven survival benefit, the role of center volume as an independent variable associated with improved outcomes is unclear.

Objective

To assess the association of high-volume centers with survival and neurological outcomes in nontraumatic OHCA.

Data Sources

Medline, Embase, and the Cochrane Central Register of Controlled Trials were searched from inception to October 11, 2021, for studies including adult patients with nontraumatic OHCA who were treated at high-volume vs non-high-volume centers.

Study Selection

Randomized clinical trials, nonrandomized studies of interventions, prospective cohort studies, and retrospective cohort studies were selected that met the following criteria: (1) adult patients with OHCA of nontraumatic etiology, (2) comparison of high-volume with low-volume centers, (3) report of a volume-outcome association, and (4) report of outcomes of interest. At least 2 authors independently reviewed each article, blinded to each other's decision.

Data Extraction and Synthesis

Data abstraction and quality assessment were independently conducted by 2 authors. Meta-analyses were performed for adjusted odds ratios (aORs) and crude ORs using a random-effects model. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline.

Main Outcomes and Measures

Survival and good neurological outcomes according to the Cerebral Performance Categories Scale at hospital discharge or 30 days.

Results

A total of 16 studies involving 82 769 patients were included. Five studies defined high volume as 40 or more cases of OHCA per year; 3 studies defined high volume as greater than 100 cases of OHCA per year. All other studies differed in definitions. Survival to discharge or 30 days improved with treatment at high-volume centers, regardless of whether aORs (1.28 [95% CI, 1.00-1.64]) or crude ORs (1.43 [95% CI, 1.09-1.87]) were pooled. There was no association between center volume and good neurological outcomes at 30 days or hospital discharge in patients with OHCA (aOR, 0.96 [95% CI, 0.77-1.20]).

Conclusions and Relevance

In this meta-analysis and systematic review, care at high-volume centers was associated with improved survival outcomes, even after adjustment for potential confounders, but was not associated with improved neurological outcomes for patients with nontraumatic OHCA. More studies evaluating the relative importance of center volume compared with other variables (eg, the availability of treatment modalities) associated with survival outcomes in patients with OHCA are required.

Direct Transport to Cardiac Arrest Center and Survival Outcomes after Out-of-Hospital Cardiac Arrest by Urbanization Level

Current guidelines for post-resuscitation care recommend regionalized care at a cardiac arrest center (CAC). Our objectives were to evaluate the effect of direct transport to a CAC on survival outcomes of out-of-hospital cardiac arrests (OHCAs), and to assess interaction effects between CAC and urbanization levels. Adult EMS-treated OHCAs with presumed cardiac etiology between 2015 and 2019 were enrolled. The main exposure was the hospital where OHCA patients were transported by EMS (CAC or non-CAC). The outcomes were good neurological recovery and survival to discharge. Multivariable logistic regression analyses were conducted. Interaction analysis between the urbanization level of the location of arrest (metropolitan or urban/rural area) and the exposure variable was performed. Among the 95,931 study population, 23,292 (24.3%) OHCA patients were transported directly to CACs. Patients in the CAC group had significantly higher likelihood of good neurological recovery and survival to discharge than the non-CAC group (both p < 0.01, aORs (95% CIs): 1.75 (1.63–1.89) and 1.70 (1.60–1.80), respectively). There were interaction effects between CAC and the urbanization level for good neurological recovery and survival to discharge. Direct transport to CAC was associated with significantly better clinical outcomes compared to non-CAC, and the findings were strengthened in OHCAs occurring in nonmetropolitan areas.

Impact of Cardiac Arrest Centers on the Survival of Patients With Nontraumatic Out-of-Hospital Cardiac Arrest: A Systematic Review and Meta-Analysis

Background

The role of cardiac arrest centers (CACs) in out‐of‐hospital cardiac arrest care systems is continuously evolving. Interpretation of existing literature is limited by heterogeneity in CAC characteristics and types of patients transported to CACs. This study assesses the impact of CACs on survival in out‐of‐hospital cardiac arrest according to varying definitions of CAC and prespecified subgroups.

Methods and Results

Electronic databases were searched from inception to March 9, 2021 for relevant studies. Centers were considered CACs if self‐declared by study authors and capable of relevant interventions. Main outcomes were survival and neurologically favorable survival at hospital discharge or 30 days. Meta‐analyses were performed for adjusted odds ratio (aOR) and crude odds ratios. Thirty‐six studies were analyzed. Survival with favorable neurological outcome significantly improved with treatment at CACs (aOR, 1.85 [95% CI, 1.52–2.26]), even when including high‐volume centers (aOR, 1.50 [95% CI, 1.18–1.91]) or including improved‐care centers (aOR, 2.13 [95% CI, 1.75–2.59]) as CACs. Survival significantly increased with treatment at CACs (aOR, 1.92 [95% CI, 1.59–2.32]), even when including high‐volume centers (aOR, 1.74 [95% CI, 1.38–2.18]) or when including improved‐care centers (aOR, 1.97 [95% CI, 1.71–2.26]) as CACs. The treatment effect was more pronounced among patients with shockable rhythm (P=0.006) and without prehospital return of spontaneous circulation (P=0.005). Conclusions were robust to sensitivity analyses, with no publication bias detected.

Conclusions

Care at CACs was associated with improved survival and neurological outcomes for patients with nontraumatic out‐of‐hospital cardiac arrest regardless of varying CAC definitions. Patients with shockable rhythms and those without prehospital return of spontaneous circulation benefited more from CACs. Evidence for bypassing hospitals or interhospital transfer remains inconclusive.

Ethics of ECPR research

The design of emergency medicine trials can raise several ethical concerns - risks may be greater, and randomisation may have to occur before consent. Research in emergency medicine is thus an illuminating context to explore the interplay between risk and randomisation, and the consequences for consent. Using a currently running trial, we describe possible concerns, considerations, and solutions to reconcile the conflicting interests of scientific inquiry, ethical principles, and clinical reality in emergency medicine research.

Analysis of Characteristics and Mortality in Cardiac Arrest Patients by Hospital Level: a Nationwide Population-based Study

BACKGROUND

Survival and post-cardiac arrest care vary considerably by hospital, region, and country. In the current study, we aimed to analyze mortality in patients who underwent cardiac arrest by hospital level, and to reveal differences in patient characteristics and hospital factors, including post-cardiac arrest care, hospital costs, and adherence to changes in resuscitation guidelines.

METHODS

We enrolled adult patients (≥ 20 years) who suffered non-traumatic cardiac arrest from 2006 to 2015. Patient demographics, insurance type, admission route, comorbidities, treatments, and hospital costs were extracted from the National Health Insurance Service database. We categorized patients into tertiary hospital, general hospital, and hospital groups according to the level of the hospital where they were treated. We analyzed the patients' characteristics, hospital factors, and mortalities among the three groups. We also analyzed post-cardiac arrest care before and after the 2010 guideline changes. The primary end-point was 30 days and 1 year mortality rates.

RESULTS

The tertiary hospital, general hospital, and hospital groups represented 32.6%, 49.6%, and 17.8% of 337,042 patients, respectively. The tertiary and general hospital groups were younger, had a lower proportion of medical aid coverage, and fewer comorbidities, compared to the hospital group. Post-cardiac arrest care, such as percutaneous coronary intervention, targeted temperature management, and extracorporeal membrane oxygenation, were provided more frequently in the tertiary and general hospital groups. After adjusting for age, sex, insurance type, urbanization level, admission route, comorbidities, defibrillation, resuscitation medications, angiography, and guideline changes, the tertiary and general hospital groups showed lower 1-year mortality (tertiary hospital vs. general hospital vs. hospital, adjusted odds ratios, 0.538 vs. 0.604 vs. 1; P < 0.001). After 2010 guideline changes, a marked decline in atropine use and an increase in post-cardiac arrest care were observed in the tertiary and general hospital groups.

CONCLUSION

The tertiary and general hospital groups showed lower 30 days and 1 year mortality rates than the hospital group, after adjusting for patient characteristics and hospital factors. Higher-level hospitals provided more post-cardiac arrest care, which led to high hospital costs, and showed good adherence to the guideline change after 2010.

The individual and neighborhood factors associated with the use of emergency medical services in patients with ST-elevation myocardial infarction

OBJECTIVE

The utilization of emergency medical services (EMS) varies widely among communities. In this study, we aimed to evaluate the relationship between the use of EMS by patients with ST-elevation myocardial infarction (STEMI) and the individual and neighborhood characteristics of these patients.

METHODS

We performed a secondary analysis of data from the Cardiovascular Disease Surveillance project, which included patients diagnosed with STEMI at 29 emergency centers in South Korea. Our analysis included only patients living in Seoul, and the primary outcome measured was the use of EMS. While the clinical variables of the patients were collected from the Cardiovascular Disease Surveillance registry, the 2010 National Census data was used to identify neighborhood variables such as population density, income, age, and residence type. We used a 3-level hierarchical logistic regression to estimate the effects of neighborhood-level factors on EMS use by individual patients.

RESULTS

We evaluated 1,634 patients with STEMI from 2007 to 2012. The neighborhoods were grouped into 25 counties. The regional rates of EMS use varied from 18.3% to 46.5%. The final adjusted logistic model revealed that the use of EMS was significantly associated with the average number of households (neighborhood level factor) and symptoms of syncope, cardiac arrest, and history of cardiovascular disease (individual level factors).

CONCLUSION

The individual levels factors had a greater influence on the use of EMS compared to the neighborhood-level factors.

Outcomes of paediatric out-of-hospital cardiac arrest according to hospital characteristic defined by the annual number of paediatric patients with invasive mechanical ventilation: A nationwide study in Japan

AIM

We examined whether outcomes of paediatric out-of-hospital cardiac arrest (OHCA) are associated with a hospital characteristic defined by the annual number of invasive mechanical ventilation cases, suggesting hospitals' experience in caring for severely ill paediatric patients.

METHOD

We analysed the Japanese Diagnosis Procedure Combination database from 2010 to 2017. We identified children (<18 years) with OHCA and post-resuscitation intensive care (defined as invasive mechanical ventilation and/or catecholamine infusion). Hospitals were divided into four groups by mean annual number of paediatric cases involving invasive mechanical ventilation. The primary outcome was in-hospital mortality, and the secondary outcome was unfavourable outcomes (death or medical care dependency at discharge). Multivariable logistic regression analyses were conducted to examine the relationship between hospitals' experience and outcomes.

RESULTS

We included 2540 paediatric OHCA patients from 385 institutions. Overall in-hospital mortality was 62.4%, with rates of 69.6%, 61.3%, 61.8%, and 57.0% in hospitals with low (≤48 cases/year), low-intermediate (48-110), high-intermediate (110-164), and high (>164) experience levels (P < .001), respectively. Compared to hospitals with low experience, adjusted odds ratios (95% confidence interval) for hospitals with low-intermediate, high-intermediate, and high experience were as follows: primary outcome: 0.64 (0.40-1.01), 0.67 (0.42-1.05), and 0.46 (0.31-0.70), respectively; secondary outcome: 0.93 (0.55-1.57), 0.95 (0.63-1.43), and 0.67 (0.46-0.96), respectively.

CONCLUSION

Japanese hospitals with higher experience in caring for severely ill paediatric patients showed lower mortality for paediatric OHCA. This fact should be considered by the Emergency Medical Systems when deciding transport strategy.

Impact of type of emergency department on the outcome of out-of-hospital cardiac arrest: a prospective cohort study

Aim

To assess whether the outcomes of out‐of‐hospital cardiac arrest (OHCA) differ between patients treated at tertiary or secondary emergency medical facilities.

Methods

Data from the Japanese Association for Acute Medicine Out‐of‐Hospital Cardiac Arrest (JAAM‐OHCA) registry between June 2014 and December 2015 were analyzed and compared between patients treated at tertiary (tertiary group) and secondary (secondary group) emergency medical facilities. The primary outcome of this study was a favorable neurological outcome at 1 and 3 months after OHCA, defined as a Glasgow–Pittsburgh cerebral performance category of 1 or 2.

Results

Between June 2014 and December 2015, a total of 13,491 patients with OHCA were registered in the JAAM‐OHCA registry. Of these, 12,836 were eligible in the present analysis, with 11,583 in the tertiary group and 1,253 in the secondary group. The proportions of patients with favorable neurological outcomes in the tertiary group were significantly higher than those in the secondary group at 1 (4.7% versus 2.0%, P < 0.001) and 3 (3.5% versus 1.6%, P < 0.001) months after OHCA. Even after adjusting for baseline characteristics of patients, treatment at a tertiary emergency medical facility was independently associated with favorable neurological outcomes at 1 (odds ratio, 2.856, 95% confidence interval, 1.429–5.710; P = 0.003) and 3 (odds ratio, 2.462, 95% confidence interval, 1.203–5.042; P = 0.014) months after OHCA.

Conclusion

The neurological outcomes of patients with OHCA treated at tertiary emergency medical facilities were better than those of patients treated at secondary emergency medical facilities.

Effect of cancer history on post-resuscitation treatments in out-of-hospital cardiac arrest

OBJECTIVES

There is growing evidence that optimal post-resuscitation treatment is a significant factor for overall survival and neurological outcomes in out-of-hospital cardiac arrest (OHCA). However, there is also growing evidence of disparities in treatments in vulnerable populations such as elderly individuals or patients with underlying diseases, including cancer.

AIM

The aim of this study was to evaluate the influence of cancer status on post-resuscitation therapies among OHCA patients.

MATERIAL AND METHODS

This was a cross-sectional observational study based on a nationwide prospective OHCA registry database of Korea. All adult OHCA patients with presumed cardiac etiology and sustained return of spontaneous circulation (ROSC) from 2009 to 2016 were included in this study. Main exposure was history of cancer and primary outcome was post-resuscitation care, including percutaneous coronary intervention (PCI) and targeted temperature management (TTM). Multivariable logistic regression was used to analyze the association between cancer and post-resuscitation treatments.

RESULTS

A total of 33,760 patients were included for final analysis. Multivariable logistic analysis showed that cancer patients were significantly less likely to receive PCI and TTM compared to those without history of cancer with adjusted odds ratios of 0.29 (95% CI: 0.24-0.37) and 0.66 (0.58-0.77), respectively.

CONCLUSION

The results of this study suggest that a prior history of cancer may be associated with lower probability to receive potentially beneficial post-resuscitation treatments.

Sensitivity, specificity, and predictive value of cardiac symptoms assessed by emergency medical services providers in the diagnosis of acute myocardial infarction: a multi-center observational study

Objective

For patients with acute myocardial infarction (AMI), symptoms assessed by emergency medical services (EMS) providers have a critical role in prehospital treatment decisions. The purpose of this study was to evaluate the diagnostic accuracy of EMS provider-assessed cardiac symptoms of AMI.

Methods

Patients transported by EMS to 4 study hospitals from 2008 to 2012 were included. Using EMS and administrative emergency department databases, patients were stratified according to the presence of EMS-assessed cardiac symptoms and emergency department diagnosis of AMI. Cardiac symptoms were defined as chest pain, dyspnea, palpitations, and syncope. Disproportionate stratified sampling was used, and medical records of sampled patients were reviewed to identify an actual diagnosis of AMI. Using inverse probability weighting, verification bias-corrected diagnostic performance was estimated.

Results

Overall, 92,353 patients were enrolled in the study. Of these, 13,971 (15.1%) complained of cardiac symptoms to EMS providers. A total of 775 patients were sampled for hospital record review. The sensitivity, specificity, positive predictive value, and negative predictive value of EMS provider-assessed cardiac symptoms for the final diagnosis of AMI was 73.3% (95% confidence interval [CI], 70.8 to 75.7), 85.3% (95% CI, 85.3 to 85.4), 3.9% (95% CI, 3.6 to 4.2), and 99.7% (95% CI, 99.7 to 99.8), respectively.

Conclusion

We found that EMS provider-assessed cardiac symptoms had moderate sensitivity and high specificity for diagnosis of AMI. EMS policymakers can use these data to evaluate the pertinence of specific prehospital treatment of AMI.

Prediction of neurological outcomes following the return of spontaneous circulation in patients with out-of-hospital cardiac arrest: Retrospective fast-and-frugal tree analysis

AIM

Although various quantitative methods have been developed for predicting neurological prognosis in patients with out-of-hospital cardiac arrest (OHCA), they are too complex for use in clinical practice. We aimed to develop a simple decision rule for predicting neurological outcomes following the return of spontaneous circulation (ROSC) in patients with OHCA using fast-and-frugal tree (FFT) analysis.

METHODS

We performed a retrospective analysis of prospectively collected data archived in a multi-centre registry. Good neurological outcomes were defined as cerebral performance category (CPC) values of 1 or 2 at 28-day. Variables used for FFT analysis included age, sex, witnessed cardiac arrest, bystander cardiopulmonary resuscitation, initial shockable rhythm, prehospital defibrillation, prehospital ROSC, no flow time, low flow time, cause of arrest (cardiac or non-cardiac), pupillary light reflex, and Glasgow Coma Scale score after ROSC.

RESULTS

Among the 456 patients enrolled, 86 (18.9%) experienced good neurological outcomes. Prehospital ROSC (true = good), prompt or sluggish light reflex response after ROSC (true = good), and presumed cardiac cause (true = good, false = poor) were selected as nodes for the decision tree. Sensitivity, specificity, positive predictive value, and negative predictive value of the decision tree for predicting good neurological outcomes were 100% (42/42), 64.0% (119/186), 38.5% (42/109), and 100% (119/119) in the training set and 95.5% (42/44), 57.6% (106/184), 35.0% (42/120), and 98.1% (106/108) in the test set, respectively.

CONCLUSION

A simple decision rule developed via FFT analysis can aid clinicians in predicting neurological outcomes following ROSC in patients with OHCA.

Out-of-Hospital Cardiac Arrest Resuscitation Systems of Care: A Scientific Statement From the American Heart Association

The American Heart Association previously recommended implementation of cardiac resuscitation systems of care that consist of interconnected community, emergency medical services, and hospital efforts to measure and improve the process of care and outcome for patients with cardiac arrest. In addition, the American Heart Association proposed a national process to develop and implement evidence-based guidelines for cardiac resuscitation systems of care. Significant experience has been gained with implementing these systems, and new evidence has accumulated. This update describes recent advances in the science of cardiac resuscitation systems and evidence of their effectiveness, as well as recent progress in dissemination and implementation throughout the United States. Emphasis is placed on evidence published since the original recommendations (ie, including and since 2010).

Variation in outcome of hospitalised patients with out-of-hospital cardiac arrest from acute coronary syndrome: a cohort study

Background

Each year, approximately 30,000 people have an out-of-hospital cardiac arrest (OHCA) that is treated by UK ambulance services. Across all cases of OHCA, survival to hospital discharge is less than 10%. Acute coronary syndrome (ACS) is a common cause of OHCA.

Objectives

To explore factors that influence survival in patients who initially survive an OHCA attributable to ACS.

Data source

Data collected by the Myocardial Ischaemia National Audit Project (MINAP) between 2003 and 2015.

Participants

Adult patients who had a first OHCA attributable to ACS and who were successfully resuscitated and admitted to hospital.

Main outcome measures

Hospital mortality, neurological outcome at hospital discharge, and time to all-cause mortality.

Methods

We undertook a cohort study using data from the MINAP registry. MINAP is a national audit that collects data on patients admitted to English, Welsh and Northern Irish hospitals with myocardial ischaemia. From the data set, we identified patients who had an OHCA. We used imputation to address data missingness across the data set. We analysed data using multilevel logistic regression to identify modifiable and non-modifiable factors that affect outcome.

Results

Between 2003 and 2015, 1,127,140 patient cases were included in the MINAP data set. Of these, 17,604 OHCA cases met the study inclusion criteria. Overall hospital survival was 71.3%. Across hospitals with at least 60 cases, hospital survival ranged from 34% to 89% (median 71.4%, interquartile range 60.7–76.9%). Modelling, which adjusted for patient and treatment characteristics, could account for only 36.1% of this variability. For the primary outcome, the key modifiable factors associated with reduced mortality were reperfusion treatment [primary percutaneous coronary intervention (pPCI) or thrombolysis] and admission under a cardiologist. Admission to a high-volume cardiac arrest hospital did not influence survival. Sensitivity analyses showed that reperfusion was associated with reduced mortality among patients with a ST elevation myocardial infarction (STEMI), but there was no evidence of a reduction in mortality in patients who did not present with a STEMI.

Limitations

This was an observational study, such that unmeasured confounders may have influenced study findings. Differences in case identification processes at hospitals may contribute to an ascertainment bias.

Conclusions

In OHCA patients who have had a cardiac arrest attributable to ACS, there is evidence of variability in survival between hospitals, which cannot be fully explained by variables captured in the MINAP data set. Our findings provide some support for the current practice of transferring resuscitated patients with a STEMI to a hospital that can deliver pPCI. In contrast, it may be reasonable to transfer patients without a STEMI to the nearest appropriate hospital.

Future work

There is a need for clinical trials to examine the clinical effectiveness and cost-effectiveness of invasive reperfusion strategies in resuscitated OHCA patients of cardiac cause who have not had a STEMI.

Funding

The National Institute for Health Research Health Services and Delivery Research programme.

Variations in Cardiac Arrest Regionalization in California

Introduction

The development of cardiac arrest centers and regionalization of systems of care may improve survival of patients with out-of-hospital cardiac arrest (OHCA). This survey of the local EMS agencies (LEMSA) in California was intended to determine current practices regarding the treatment and routing of OHCA patients and the extent to which EMS systems have regionalized OHCA care across California.

Methods

We surveyed all of the 33 LEMSA in California regarding the treatment and routing of OHCA patients according to the current recommendations for OHCA management.

Results

Two counties, representing 29% of the California population, have formally regionalized cardiac arrest care. Twenty of the remaining LEMSA have specific regionalization protocols to direct all OHCA patients with return of spontaneous circulation to designated percutaneous coronary intervention (PCI)-capable hospitals, representing another 36% of the population. There is large variation in LEMSA ability to influence inhospital care. Only 14 agencies (36%), representing 44% of the population, have access to hospital outcome data, including survival to hospital discharge and cerebral performance category scores.

Conclusion

Regionalized care of OHCA is established in two of 33 California LEMSA, providing access to approximately one-third of California residents. Many other LEMSA direct OHCA patients to PCI-capable hospitals for primary PCI and targeted temperature management, but there is limited regional coordination and system quality improvement. Only one-third of LEMSA have access to hospital data for patient outcomes.

Admission levels of high-density lipoprotein and apolipoprotein A-1 are associated with the neurologic outcome in patients with out-of-hospital cardiac arrest

Objective

To investigate whether serum levels of high-density lipoprotein (HDL) and apolipoprotein A-1 (ApoA1), after the return of spontaneous circulation, can predict the neurologic outcome in patients with out-of-hospital cardiac arrest (OHCA).

Methods

This was a retrospective observational study conducted in a single tertiary hospital intensive care unit. All adult OHCA survivors with admission lipid profiles were enrolled from March 2013 to December 2015. Good neurologic outcome was defined as discharge cerebral performance categories 1 and 2.

Results

Among 59 patients enrolled, 13 (22.0%) had a good neurologic outcome. Serum levels of HDL (56.7 vs. 40 mg/dL) and ApoA1 (117 vs. 91.6 mg/dL) were significantly higher in patients with a good outcome. Areas under the HDL and ApoA1 receiver operating curves to predict good outcomes were 0.799 and 0.759, respectively. The proportion of good outcome was significantly higher in patients in higher tertiles of HDL and ApoA1 (test for trend, both P=0.003). HDL (P=0.018) was an independent predictor in the multivariate logistic regression model.

Conclusion

Admission levels of HDL and ApoA1 are associated with neurologic outcome in patients with OHCA. Prognostic and potential therapeutic values of HDL and ApoA1 merit further evaluation in the post-cardiac arrest state, as in other systemic inflammatory conditions such as sepsis.

Cardiac arrest while exercising on mountains in national or provincial parks: A national observational study from 2012 to 2015

BACKGROUND

Previous studies on cardiac arrest in mountainous areas were focused on environmental features such as altitude and temperature. However, those are limited to factors affecting the prognosis of patients after cardiac arrest. We analyzed the cardiac arrests in national or provincial parks located in the mountains and determined the factors affecting the prognosis of patients after cardiac arrest.

METHODS

This study included all emergency medical service (EMS) treated patients over the age of 40 experiencing out-of-hospital cardiac arrests (OHCAs) of presumed cardiac etiology during exercise, between January 2012 and December 2015. The main focus of interest was the location of cardiac arrest occurrence (national mountain parks and provincial parks vs. other sites). The main outcome was survival to discharge and multivariable logistic regression was performed to adjust for possible confounding effects.

RESULTS

A total 1835 patients who suffered a cardiac arrest while exercising were included. From these, 68 patients experienced cardiac arrest in national or provincial parks, and 1767 occurred in other locations. The unadjusted and adjusted ORs (95% CI) for a good cerebral performance scale (CPC) were 0.09 (0.01-0.63) and 0.08(0.01-0.56), survival discharges were 0.13(0.03-0.53) and 0.11 (0.03-0.48).

CONCLUSIONS

Cardiac arrests occurring while exercising in the mountainous areas have worse prognosis compared to alternative locations.

Prehospital Supraglottic Airway Was Associated With Good Neurologic Outcome in Cardiac Arrest Victims Especially Those Who Received Prolonged Cardiopulmonary Resuscitation

OBJECTIVES

We performed this study to investigate the association of prehospital supraglottic airway (SGA) on neurologic outcome in cardiac arrest victims with adjustment of postresuscitation variables as well as prehospital and resuscitation variables.

METHODS

This study was a retrospective study based on a multicenter prospective cohort registry from December 2013 to April 2016. According to the 28-day cerebral performance categories (CPCs) scale, patients were divided into the good-outcome group (CPC 1-2) and the poor-outcome group (CPC 3-5). We compared the two groups with respect to demographic variables, prehospital and in-hospital resuscitation variables, and postresuscitation variables.

RESULTS

A total of 869 cardiac arrest victims who received in-progress cardiopulmonary resuscitation (CPR) were delivered to the emergency department of three hospitals, and 310 patients were admitted to the intensive care unit. The use of a prehospital SGA was independently associated with 28-day good neurologic outcome (odds ratio [OR] = 7.88; 95% confidence interval [CI] = 1.33-46.53; p = 0.023] when postresuscitation variables were adjusted, although there were no significant association with the acquisition of sustained return of spontaneous circulation (OR = 0.992; 95% CI = 0.591-1.666; p = 0.976). Furthermore, a prehospital SGA was significantly associated with good neurologic outcome, especially in patients who received prolonged CPR (low flow time > 15 minutes; OR = 3.41; 95% CI = 1.23-9.45; p = 0.018) rather than in patients with nonprolonged CPR (OR = 4.50; 95% CI = 0.75-27.13; p = 0.101).

CONCLUSIONS

When postresuscitation variables were adjusted, the prehospital SGA was independently associated with 28-day good neurologic outcome in cardiac arrest victims.

Hospital characteristics and favourable neurological outcome among patients with out-of-hospital cardiac arrest in Osaka, Japan

OBJECTIVE

To assess the association between favourable neurological outcome and hospital characteristics such as hospital volume and number of critical care centres (CCMCs) after out-of-hospital cardiac arrest (OHCA).

METHODS

This retrospective, population-based observational study conducted in Osaka Prefecture, Japan included adult patients with OHCA, aged ≥18 years who were transported to acute care hospitals between January 2005 and December 2012. We divided acute care hospitals into CCMCs or non-CCMCs, the latter of which were divided into the following three groups according to the annual average number of transported OHCA cases: low-volume (≤10 cases), middle-volume (11-39 cases), and high-volume (≥40 cases) groups. Random effects logistic regression models, with hospital treated as a random effect, were used to assess factors potentially associated with a favourable neurological outcome.

RESULTS

A total of 44,474 patients were eligible. The proportions of favourable neurological outcome from OHCA were 0.9% (31/3559) in the low-volume group, 1.2% (106/9171) in the middle-volume group, 1.6% (222/14,007) in the high-volume group, and 4.3% (766/17,737) in the CCMC group (P<0.001). In the multivariable analysis, transport to CCMCs was significantly associated with favourable neurological outcome, compared with transport to non-CCMCs (adjusted odds ratio 1.63; 95% confidence interval, 1.60-1.66). Among the non-CCMC group, there was no significant relationship between hospital volume and favourable neurological outcome.

CONCLUSIONS

In this population, transport of OHCA patients to CCMCs led to significantly higher one-month survival rates with favourable neurological outcome from OHCA, whereas no significant association was noted among the hospitals with different volumes.

A survey-based study on the protocols for therapeutic hypothermia in cardiac arrest patients in Korea: focusing on the differences between level 1 and 2 centers

OBJECTIVE

We aimed to summarize the therapeutic hypothermia (TH) protocols used in emergency departments (EDs) in Korea and to investigate the differences between level 1 and 2 centers.

METHODS

The chief residents from 56 EDs were given a structured survey containing questions on the indications for TH, methods for TH induction, maintaining, and finalizing TH treatments. The participants were divided into 2 groups based on their work place (level 1 vs. level 2 centers).

RESULTS

We received 36 responses to the survey. The majority of the participants (94.4%) reported that they routinely used TH. An average of 5.9 (standard deviation, 3.4) and 3.3 (standard deviation, 2.9) TH procedures were performed monthly in level 1 and 2 centers, respectively (P=0.01). The majority of level 1 and 2 centers (80.0% and 73.1%, respectively) had written TH protocols. Rectal (50.0%) and esophageal probes (38.9%) were most commonly used to monitor the patients' body temperatures. Midazolam (80.6%) and remifentanyl (47.2%) were the most commonly used sedatives. For TH induction, external cooling devices (77.8%) and cold saline infusion (66.1%) were predominant. Between level 1 and 2 centers, only the number of TH, the usage of remifentanyl, and application of external cooling device showed significant differences (P<0.05).

CONCLUSION

Our study summarizes the TH protocols used in 36 EDs. The majority of study participants performed TH using a written protocol. We observed small number of differences in TH induction and maintenance methods between level 1 and 2 centers.

Effect of Dispatcher-Assisted Cardiopulmonary Resuscitation Program and Location of Out-of-Hospital Cardiac Arrest on Survival and Neurologic Outcome

STUDY OBJECTIVE

We study the effect of a nationwide dispatcher-assisted cardiopulmonary resuscitation (CPR) program on out-of-hospital cardiac arrest outcomes by arrest location (public and private settings).

METHODS

All emergency medical services (EMS)-treated adults in Korea with out-of-hospital cardiac arrests of cardiac cause were enrolled between 2012 and 2013, excluding cases witnessed by EMS providers and those with unknown outcomes. Exposure was bystander CPR categorized into 3 groups: bystander CPR with dispatcher assistance, bystander CPR without dispatcher assistance, and no bystander CPR. The endpoint was good neurologic recovery at discharge. Multivariable logistic regression analysis was performed. The final model with an interaction term was evaluated to compare the effects across settings.

RESULTS

A total of 37,924 patients (31.1% bystander CPR with dispatcher assistance, 14.3% bystander CPR without dispatcher assistance, and 54.6% no bystander CPR) were included in the final analysis. The total bystander CPR rate increased from 30.9% in quarter 1 (2012) to 55.7% in quarter 4 (2014). Bystander CPR with and without dispatcher assistance was more likely to result in higher survival with good neurologic recovery (4.8% and 5.2%, respectively) compared with no bystander CPR (2.1%). The adjusted odds ratios for good neurologic recovery were 1.50 (95% confidence interval [CI] 1.30 to 1.74) in bystander CPR with dispatcher assistance and 1.34 (95% CI 1.12 to 1.60) in bystander CPR without it compared with no bystander CPR. For arrests in private settings, the adjusted odds ratios were 1.58 (95% CI 1.30 to 1.92) in bystander CPR with dispatcher assistance and 1.28 (95% CI 0.98 to 1.67) in bystander CPR without it; in public settings, the adjusted odds ratios were 1.41 (95% CI 1.14 to 1.75) and 1.37 (95% CI 1.08 to 1.72), respectively.

CONCLUSION

Bystander CPR regardless of dispatcher assistance was associated with improved neurologic recovery after out-of-hospital cardiac arrest. However, for out-of-hospital cardiac arrest cases in private settings, bystander CPR was associated with improved neurologic recovery only when dispatcher assistance was provided.

Effect of therapeutic hypothermia on the outcomes after out-of-hospital cardiac arrest according to initial ECG rhythm and witnessed status: A nationwide observational interaction analysis

BACKGROUND

The use of mild therapeutic hypothermia (TH) in out-of-hospital cardiac arrest (OHCA) with shockable rhythms is recommended and widely used. However, it is unclear whether TH is associated with better outcomes in non-shockable rhythms.

METHODS

This is a retrospective observational study using a national OHCA cohort database composed of emergency medical services (EMS) and hospital data. We included adult EMS-treated OHCA patients of presumed cardiac etiology who were admitted to the hospital during Jan. 2008 to Dec. 2013. Patients without hospital outcome data were excluded. The primary outcome was good neurological outcome at discharge; secondary outcome was survival to discharge. The primary exposure was TH. We compared outcomes between TH and non-TH groups using multivariable logistic regression, adjusting for individual and Utstein factors. Interactions of initial ECG rhythm and witnessed status on the effect of TH on outcomes were tested.

RESULTS

There were 11,256 patients in the final analysis. TH was performed in 1703 patients (15.1%). Neurological outcome was better in TH (23.5%) than non-TH (15.0%) (Adjusted OR=1.25, 95% CI 1.05-1.48). The effect of TH on the odds for good neurological outcome was highest in the witnessed PEA group (Adjusted OR=3.91, 95% CI 1.87-8.14). Survival to discharge was significantly higher in the TH group (55.1%) than non-TH (35.9%) (Adjusted OR=1.76, 95% CI 1.56-2.00).

CONCLUSIONS

In a nationwide observational study, TH is associated with better neurological outcome and higher survival to discharge. The effect of TH is greatest in witnessed OHCA patients with PEA as the initial ECG rhythm.

The Volume-Outcome Relationship in Critical Care: A Systematic Review and Meta-analysis

OBJECTIVE

The purpose of this study was to systematically review the research on volume and outcome relationships in critical care.

METHODS

From January 1, 2001, to April 30, 2014, MEDLINE and EMBASE were searched for studies assessing the relationship between admission volume and clinical outcomes in critical illness. Bibliographies were reviewed to identify other articles of interest, and experts were contacted about missing or unpublished studies. Of 127 studies reviewed, 46 met inclusion criteria, covering seven clinical conditions. Two investigators independently reviewed each article using a standardized form to abstract information on key study characteristics and results.

RESULTS

Overall, 29 of the studies (63%) reported a statistically significant association between higher admission volume and improved outcomes. The magnitude of the association (mortality OR between the lowest vs highest stratum of volume centers), as well as the thresholds used to characterize high volume, varied across clinical conditions. Critically ill patients with cardiovascular (n = 7, OR = 1.49 [1.11-2.00]), respiratory (n = 12, OR = 1.20 [1.04-1.38]), severe sepsis (n = 4, OR = 1.17 [1.03-1.33]), hepato-GI (n = 3, OR = 1.30 [1.08-1.78]), neurologic (n = 3, OR = 1.38 [1.22-1.57]), and postoperative admission diagnoses (n = 3, OR = 2.95 [1.05-8.30]) were more likely to benefit from admission to higher-volume centers compared with lower-volume centers. Studies that controlled for ICU or hospital organizational factors were less likely to find a significant volume-outcome relationship than studies that did not control for these factors.

CONCLUSIONS

Critically ill patients generally benefit from care in high-volume centers, with more substantial benefits in selected high-risk conditions. This relationship may in part be mediated by specific ICU and hospital organizational factors.

Association between treatment at an ST-segment elevation myocardial infarction center and neurologic recovery after out-of-hospital cardiac arrest

BACKGROUND

For patients resuscitated from out-of-hospital cardiac arrest (OHCA), the American Heart Association recommends regionalized care at cardiac resuscitation centers that are aligned with ST-segment elevation myocardial infarction (STEMI) centers. The effectiveness of treatment at STEMI centers remains unknown.

OBJECTIVE

To evaluate whether good neurologic recovery after OHCA is associated with treatment at an STEMI center and if volume of admitted OHCA patients is associated with good neurologic recovery.

METHODS

We included patients in the 2011 California Office of Statewide Health Planning and Development database with a "present on admission" diagnosis of cardiac arrest. Primary outcome was good neurologic recovery at hospital discharge. Hierarchical multiple logistic regression models were used to determine the association between treating hospital and good neurologic recovery after adjusting for patient factors (age, sex, race, ethnicity, insurance type, and ventricular arrest rhythm) and hospital factors (hospital size, intensive care unit bed days, trauma center designation, and teaching status).

RESULTS

We included 7,725 patients; two-thirds (5,202) were treated at an STEMI center and 1,869 (24%, 95% CI 23%-25%) had good neurologic recovery. After adjustment, treatment at an STEMI center with ≥40 and <40 OHCA cases/year were associated with good neurologic recovery (odds ratio 1.32 [95% CI 1.06-1.64] and 1.63 [95% CI 1.35-1.97], respectively). Higher volume of admitted OHCA patients was associated with decreased odds of good neurologic recovery (adjusted odds ratio per 10 patients 0.96, 95% CI 0.92-1.00), but this association was not statistically significant after excluding the highest-volume outlier.

CONCLUSIONS

Treatment at an STEMI center-regardless of its annual OHCA volume-after resuscitation from OHCA is associated with good neurologic recovery. Regionalized systems of care should prioritize STEMI centers as destinations for resuscitated OHCA patients.

Epidemiology and outcomes of out-of-hospital cardiac arrest according to suicide mechanism: a nationwide observation study

Objective

Suicide remains a serious, preventable public health problem. This study aims to describe the epidemiological characteristics associated with various suicide methods and to investigate outcomes after suicide-associated sudden cardiac arrest (S-SCA), stratified by different suicide attempt methods.

Methods

An S-SCA database was constructed from ambulance run sheets and augmented by a review of hospital medical records from 2008 to 2010 in Korea. The cases with non-cardiac etiologies and suicide attempts were initially extracted. Suicide attempts were classified as hanging, poisoning, fall, and other. The primary end point was survival to discharge. Age- and sex-adjusted incidence rates were calculated for each suicide method. Adjusted odds ratios for outcome were calculated with adjustments for potential confounding variables.

Results

A total 5,743 patients were analyzed as S-SCAs. The most common method of suicide attempt was hanging (58.7%), followed by falls (17.6%), poisoning (17.5%), and others (5.8%). The survival to discharge rates were 2.1% (n=119) overall, 2.4% in hanging, 2.4% in poisoning and 0.5% in fall, respectively. The age- and sex-adjusted incidence rates (male/female) per million persons was 32.7 (35.8/29.7) in 2008, 41.8 (46.0/37.7) in 2009, and 43.0 (50.1/36.0) in 2010. Compared with hanging, adjusted odds ratios (95% confidence intervals) for survival to discharge was 1.05 (0.60 to 1.83) for poisoning and 0.08 (0.03 to 0.21) for falls.

Conclusion

In this nationwide S-SCA cohort study from 2008 to 2010, the standardized incidence rate increased annually. However, the rate of survival to discharge remains very low.

Temporal trends in out-of-hospital cardiac arrest survival outcomes between two metropolitan communities: Seoul-Osaka resuscitation study

OBJECTIVES

The objective of this study was to compare the temporal trends in survival after out-of-hospital cardiac arrest (OHCA) between two large metropolitan communities in Asia and evaluate the factors affecting survival after OHCA.

DESIGN

A population-based prospective observational study.

SETTING

The Cardiovascular Disease Surveillance (CAVAS) project in Seoul and the Utstein Osaka Project in Osaka.

PARTICIPANTS

A total of 36,292 resuscitation-attempted OHCAs with cardiac aetiology from 2006 to 2011 in Seoul and Osaka (11,082 in Seoul and 25,210 in Osaka).

PRIMARY OUTCOME MEASURES

The primary outcome was neurologically favourable survival. Trend analysis and multivariable Poisson regression models were conducted to evaluate the temporal trends in survival of two communities.

RESULTS

During the study period, the overall neurologically favourable survival was 2.6% in Seoul and 4.6% in Osaka (p<0.01). In both communities, bystander cardiopulmonary resuscitation (CPR) rates increased significantly from 2006 to 2011 (from 0.1% to 13.1% in Seoul and from 33.3% to 41.7% in Osaka). OHCAs that occurred in public places increased in Seoul (12.5% to 20.1%, p for trend <0.01) and decreased in Osaka (13.5% to 10.5%, p for trend <0.01). The proportion of OHCAs defibrillated by emergency medical service (EMS) providers was only 0.4% in 2006 but increased to 17.5% in 2011 in Seoul, whereas the proportion in Osaka decreased from 17.7% to 13.7% (both p for trend <0.01). Age-adjusted and gender-adjusted rates of neurologically favourable survival increased significantly in Seoul from 1.4% in 2006 to 4.3% in 2011 (adjusted rate ratio per year, 1.17; p for trend <0.01), whereas no significant improvement was observed in Osaka (3.6% in 2006 and 5.1% in 2011; adjusted rate ratio per year, 1.03; p for trend=0.08).

CONCLUSIONS

Survivals after OHCA were increased in Seoul while remained constant in Osaka, which may have been affected by the differences and improvements of patient, community, and EMS system factors.

Quality of post arrest care does not differ by time of day at a specialized resuscitation center

Previous studies suggest worse outcomes after out-of-hospital cardiac arrest (OHCA) at night. We analyzed whether patients admitted after nontraumatic OHCA to a resuscitation center received the same quality post arrest care at day and night and whether quality of care affected clinical outcomes. We analyzed data of OHCA patients with return of spontaneous circulation admitted to the Vienna general hospital emergency department between January 2006 and May 2013. Data reported include admission time (day defined from 8 AM to 4 PM based on staffing), time to initiation of hypothermia, and door-to-balloon time in patients with ST-elevation myocardial infarction. Survival and cognitive performance at 12 months were assessed. In this retrospective observational study, 1059 patients (74% males, n = 784) with a mean age of 58 ± 16 years were analyzed. The vast majority was treated with induced hypothermia (77% of day vs. 79% of night admissions, P = 0.32) within 1 hour of admission (median time admission to cooling 27 (confidence interval [CI]: 10-60) vs. 23 (CI: 11-59) minutes day vs. night, P = 0.99). In 298 patients with ST-elevation myocardial infarction, median door-to-balloon time did not differ between day and night admissions (82 minutes, CI: 60 to 142 for day vs. 86 minutes, CI: 50 to 135 for night, P = 0.36). At 12 months, survival was recorded in 238 of 490 day and 275 of 569 night admissions (49% vs. 48%, P = 0.94%), and a good neurologic outcome was recorded in 210 of 490 day and 231 of 569 night admissions (43% vs. 41%, P = 0.46). Patients admitted to our department after OHCA were equally likely to receive timely high-quality postresuscitation care irrespective of time of day. Survival and good neurologic outcome at 12 months did not differ between day and night admissions. Our results may support the concept of specialized post arrest care centers.

An observational study of surface versus endovascular cooling techniques in cardiac arrest patients: a propensity-matched analysis

INTRODUCTION

Various methods and devices have been described for cooling after cardiac arrest, but the ideal cooling method remains unclear. The aim of this study was to compare the neurological outcomes, efficacies and adverse events of surface and endovascular cooling techniques in cardiac arrest patients.

METHODS

We performed a multicenter, retrospective, registry-based study of adult cardiac arrest patients treated with therapeutic hypothermia presenting to 24 hospitals across South Korea from 2007 to 2012. We included patients who received therapeutic hypothermia using overall surface or endovascular cooling devices and compared the neurological outcomes, efficacies and adverse events of both cooling techniques. To adjust for differences in the baseline characteristics of each cooling method, we performed one-to-one matching by the propensity score.

RESULTS

In total, 803 patients were included in the analysis. Of these patients, 559 underwent surface cooling, and the remaining 244 patients underwent endovascular cooling. In the unmatched cohort, a greater number of adverse events occurred in the surface cooling group. Surface cooling was significantly associated with a poor neurological outcome (cerebral performance category 3-5) at hospital discharge (p = 0.01). After propensity score matching, surface cooling was not associated with poor neurological outcome and hospital mortality [odds ratio (OR): 1.26, 95% confidence interval (CI): 0.81-1.96, p = 0.31 and OR: 0.85, 95% CI: 0.55-1.30, p = 0.44, respectively]. Although surface cooling was associated with an increased incidence of adverse events (such as overcooling, rebound hyperthermia, rewarming related hypoglycemia and hypotension) compared with endovascular cooling, these complications were not associated with surface cooling using hydrogel pads.

CONCLUSIONS

In the overall matched cohort, no significant difference in neurological outcomes and hospital morality was observed between the surface and endovascular cooling methods.

Epidemiology and outcomes in out-of-hospital cardiac arrest: a report from the NEDIS-based cardiac arrest registry in Korea

Sudden cardiac death (SCD) is a significant issue affecting national health policies. The National Emergency Department Information System for Cardiac Arrest (NEDIS-CA) consortium managed a prospective registry of out-of-hospital cardiac arrest (OHCA) at the emergency department (ED) level. We analyzed the NEDIS-CA data from 29 participating hospitals from January 2008 to July 2009. The primary outcomes were incidence of OHCA and final survival outcomes at discharge. Factors influencing survival outcomes were assessed as secondary outcomes. The implementation of advanced emergency management (drugs, endotracheal intubation) and post-cardiac arrest care (therapeutic hypothermia, coronary intervention) was also investigated. A total of 4,156 resuscitation-attempted OHCAs were included, of which 401 (9.6%) patients survived to discharge and 79 (1.9%) were discharged with good neurologic outcomes. During the study period, there were 1,662,470 ED visits in participant hospitals; therefore, the estimated number of resuscitation-attempted CAs was 1 per 400 ED visits (0.25%). Factors improving survival outcomes included younger age, witnessed collapse, onset in a public place, a shockable rhythm in the pre-hospital setting, and applied advanced resuscitation care. We found that active advanced multidisciplinary resuscitation efforts influenced improvement in the survival rate. Resuscitation by public witnesses improved the short-term outcomes (return of spontaneous circulation, survival admission) but did not increase the survival to discharge rate. Strategies are required to reinforce the chain of survival and high-quality cardiopulmonary resuscitation in Korea.

Impact of case volume on outcome and performance of targeted temperature management in out-of-hospital cardiac arrest survivors

PURPOSE

This study aimed to determine the effect of case volume on targeted temperature management (TTM) performance, incidence of adverse events, and neurologic outcome in comatose out-of-hospital cardiac arrest (OHCA) survivors treated with TTM.

METHODS

We used a Web-based, multicenter registry (Korean Hypothermia Network registry), to which 24 hospitals throughout the Republic of Korea participated to study adult (≥18 years) comatose out-of-hospital cardiac arrest patients treated with TTM between 2007 and 2012. The primary outcome was neurologic outcome at hospital discharge. The secondary outcomes were inhospital mortality, TTM performance, and adverse events. We extracted propensity-matched cohorts to control for bias. Multivariate logistic regression analysis was performed to assess independent risk factors for neurologic outcome.

RESULTS

A total of 901 patients were included in this study; 544 (60.4%) survived to hospital discharge, and 248 (27.5%) were discharged with good neurologic outcome. The high-volume hospitals initiated TTM significantly earlier and had lower rates of hyperglycemia, bleeding, hypotension, and rebound hyperthermia. However, neurologic outcome and inhospital mortality were comparable between high-volume (27.7% and 44.6%, respectively) and low-volume hospitals (21.1% and 40.5%) in the propensity-matched cohorts. The adjusted odds ratio for the high-volume hospitals compared with low-volume hospitals was 1.506 (95% confidence interval, 0.875-2.592) for poor neurologic outcome.

CONCLUSIONS

Higher TTM case volume was significantly associated with early initiation of TTM and lower incidence of adverse events. However, case volume had no association with neurologic outcome and inhospital mortality.

Epidemiology and outcomes of in-hospital cardiac arrest in critically ill children across hospitals of varied center volume: a multi-center analysis

OBJECTIVE

To describe epidemiology and outcomes associated with cardiac arrest among critically ill children across hospitals of varying center volumes.

METHODS

Patients <18 years of age in the Virtual PICU Systems (VPS, LLC) Database (2009-2013) were included. Patients with both cardiac and non-cardiac diagnoses were included. Data on demographics, patient diagnosis, cardiac arrest, severity of illness and outcomes were collected. Hierarchical cluster analysis was performed to categorize all the participating centers into low, low-medium, high-medium, and high volume groups using the center volume characteristics (annual hospital discharges per center, annual extracorporeal membrane oxygenation per center, and annual mechanical ventilators per center). Multivariable models were used to evaluate association of center volume with incidence of cardiac arrest, and mortality after cardiac arrest, adjusting for patient and center characteristics.

RESULTS

Of 329,982 patients (108 centers), 2.2% (n=7390) patients had cardiac arrest with an associated mortality of 35% (n=2586). In multivariable models controlling for patient and center characteristics, center volume was not associated with either the incidence of cardiac arrest (OR: 1.00; 95% CI: 0.95-1.06; p=0.98), or mortality in those with cardiac arrest (OR: 0.93; 95% CI: 0.82-1.06; p=0.27). These associations were similar across cardiac and non-cardiac disease categories. Furthermore, we demonstrated that there was no correlation between incidence of cardiac arrest and mortality in those with cardiac arrest across different study hospitals in adjusted models.

CONCLUSIONS

Both incidence of cardiac arrest, and mortality in those with cardiac arrest vary substantially across hospitals. However, center volume is not associated with either of these outcomes, after adjusting for patient and center characteristics.

Association between resuscitation time interval at the scene and neurological outcome after out-of-hospital cardiac arrest in two Asian cities

BACKGROUND AND AIM

It is unclear whether the scene time interval (STI) for cardiopulmonary resuscitation (CPR) is associated with outcomes of out-of-hospital cardiac arrest (OHCA) or not. The present study aimed to determine the association between STI and neurological outcome after OHCA using two large population-based cohorts covering two metropolitan cities in Asia.

METHODS

A retrospective analysis based on two large population-based cohorts from Seoul (2008-2010) and Osaka (2007-2009) was performed for witnessed adult OHCA with presumed cardiac aetiology. The STI, defined as time from wheel arrival at the scene to departure to hospital, was categorised as short (<8min), intermediate (from 8 to <16min) and long (16min or longer) STI on the basis of sensitivity analysis. The primary outcome was good neurological outcome (cerebral performance category 1 or 2). Adjusted odds ratios (AORs) with 95% confidence intervals (CIs) were calculated to determine the association between STIs and outcomes in comparison to the short STI group adjusting for potential risk factors and interaction products.

RESULTS

A total of 7757 patients, 3594 from Seoul and 4163 from Osaka, were finally analysed. There were significant differences among the STI groups for most potential risk variables. Survival to admission was higher in the intermediate STI group (35.7%) than in the short (31.8%) or long STI group (32.6%) (p=0.004). Survival to discharge was not different among groups, at 13.7%, 13.1% and 11.5%, respectively (p=0.094). The intermediate STI group had a significantly better neurological outcome compared with the short STI group (7.7% vs. 4.6%; AOR=1.32; 95% CI, 1.03-1.71), while the long STI (6.6%) did not.

CONCLUSION

Data from two metropolitan cities demonstrated a positive association between intermediate STI from 8 to 16min and good neurological outcome after OHCA.