Interhospital transfer in low-volume and high-volume emergency departments and survival outcomes after out-of-hospital cardiac arrest: A nationwide observational study and propensity score–matched analysis

Factors influencing support for the implementation of community-based out-of-hospital cardiac arrest interventions in high- and low-performing counties

Aim of the study

Survival to hospital discharge from out-of-hospital cardiac arrest (OHCA) after receiving treatment from emergency medical services (EMS) is less than 10% in the United States. Community-focused interventions improve survival rates, but there is limited information on how to gain support for new interventions or program activities within these populations. Using data from the RAndomized Cluster Evaluation of Cardiac ARrest Systems (RACE-CARS) trial, we aimed to identify the factors influencing emergency response agencies' support in implementing an OHCA intervention.

Methods

North Carolina counties were stratified into high-performing or low-performing counties based on the county's cardiac arrest volume, percent of bystander-cardiopulmonary resuscitation (CPR) performed, patient survival to hospital discharge, cerebral performance in patients after cardiac arrest, and perceived engagement in the RACE-CARS project. We randomly selected 4 high-performing and 3 low-performing counties and conducted semi-structured qualitative interviews with emergency response stakeholders in each county.

Results

From 10/2021 to 02/2022, we completed 29 interviews across the 7 counties (EMS (n = 9), telecommunications (n = 7), fire/first responders (n = 7), and hospital representatives (n = 6)). We identified three themes salient to community support for OHCA intervention: (1) initiating support at emergency response agencies; (2) obtaining support from emergency response agency staff (senior leadership and emergency response teams); and (3) and maintaining support. For each theme, we described similarities and differences by high- and low-performing county.

Conclusions

We identified techniques for supporting effective engagement of emergency response agencies in community-based interventions for OHCA improving survival rates. This work may inform future programs and initiatives around implementation of community-based interventions for 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.

Low serum cholesterol level as a risk factor for out-of-hospital cardiac arrest: a case-control study

OBJECTIVE

We aimed to identify the association between low serum total cholesterol levels and the risk of out-of-hospital cardiac arrest (OHCA).

METHODS

This case-control study was performed using datasets from the Cardiac Arrest Pursuit Trial with Unique Registration and Epidemiologic Surveillance (CAPTURES) project and the Korea National Health and Nutrition Examination Survey (KNHANES). Cases were defined as emergency medical service-treated adult patients who experienced OHCA with a presumed cardiac etiology from the CAPTURES project dataset. Four controls from the KNHANES dataset were matched to each case based on age, sex, and county. Multivariable conditional logistic regression analysis was conducted to evaluate the effect of total cholesterol levels on OHCA.

RESULTS

A total of 607 matched case-control pairs were analyzed. We classified total cholesterol levels into six categories (<148, 148-166.9, 167-189.9, 190-215.9, 216-237.9, and ≥238 mg/dL) according to the distribution of total cholesterol levels in the KNHANES dataset. Subjects with a total cholesterol level of 167-189.9 mg/dL (25th-49th percentile of the KNHANES dataset) were used as the reference group. In both the adjusted models and sensitivity analysis, a total cholesterol level of <148 mg/dL was significantly associated with OHCA (adjusted odds ratio [95% confidence interval], 6.53 [4.47-9.56]).

CONCLUSION

We identified an association between very-low total cholesterol levels and an increased risk of OHCA in a large, community-based population. Future prospective studies are needed to better understand how a low lipid profile is associated with OHCA.

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.

Inter-Hospital Transfer after Return of Spontaneous Circulation Shows no Correlation with Neurological Outcomes in Cardiac Arrest Patients Undergoing Targeted Temperature Management in Cardiac Arrest Centers

This study evaluated whether inter-hospital transfer (IHT) after the return of spontaneous circulation (ROSC) was associated with poor neurological outcomes after 6 months in post-cardiac-arrest patients treated with targeted temperature management (TTM). We used data from the Korean Hypothermia Network prospective registry from November 2015 to December 2018. These out-of-hospital cardiac arrest (OHCA) patients had either received post-cardiac arrest syndrome (PCAS) care at the same hospital or had been transferred from another hospital after ROSC. The primary endpoint was the neurological outcome 6 months after cardiac arrest. Subgroup analyses were performed to determine differences in the time from ROSC to TTM induction according to the electrocardiography results after ROSC. We enrolled 1326 patients. There were no significant differences in neurological outcomes between the direct visit and IHT groups. In patients without ST elevation, the mean time to TTM was significantly shorter in the direct visit group than in the IHT group. IHT after achieving ROSC was not associated with neurologic outcomes after 6 months in post-OHCA patients treated with TTM, even though TTM induction was delayed in transferred patients.

Association between health insurance status and transfer of patients with return of spontaneous circulation after out-of-hospital cardiac arrest

AIM

To explore the factors related to the probability of inter-hospital transfer to a heart attack centre in patients with return of spontaneous circulation after out-of-hospital cardiac arrest (OHCA) in the Republic of Korea.

METHODS

This cross-sectional observational study used data from a Korean national emergency medical service OHCA database for cases between 2015 and 2017. Adult OHCA patients with a presumed cardiac origin who initially presented at a non-heart-attack centre were included in the analysis. The main exposure variable was health insurance type (national health insurance versus medical aid), which was used as a proxy measure of individual socioeconomic status. The primary outcome was emergency department disposition (transfer to a heart attack centre versus no transfer). A multivariate logistic analysis using propensity score matching was conducted. We also analysed the associations between patient transfer and neurologic recovery as well as survival to discharge.

RESULTS

Of 7804 eligible OHCA patients, 1804 23.0%) were transferred to a heart attack centre. Patients on medical aid were less likely to be transferred (adjusted odds ratio [OR], 0.75; 95% confidence interval [CI], 0.59-0.95 in a matched cohort) compared with patients with national health insurance. Transfer to a heart attack centre was significantly associated with a lower risk of death (adjusted OR, 0.38; 95% CI, 0.33-0.45) and better neurologic recovery (adjusted OR, 0.46; 95% CI, 0.38-0.56).

CONCLUSION

Socioeconomic status appears likely to influence the probability of transfer to a heart attack centre after resuscitation.