Elsevier

Resuscitation

Volume 84, Issue 8, August 2013, Pages 1068-1077
Resuscitation

Clinical paper
Post-resuscitation care and outcomes of out-of-hospital cardiac arrest: A nationwide propensity score-matching analysis

https://doi.org/10.1016/j.resuscitation.2013.02.010Get rights and content

Abstract

Objective

This study aimed to determine whether active post-resuscitation care (APRC) was associated with improved out-of-hospital cardiac arrest (OHCA) outcomes on a nationwide level.

Methods and results

We used a national OHCA cohort database consisting of hospital and ambulance data. We included all survivors of OHCA, excluding patients with non-cardiac etiology, younger than 15 years, and with unknown outcomes, from (2008 to 2010). The APRC was defined when the OHCA patients received mild therapeutic hypothermia (MTH) or active cardiac care (ACC), such as intravenous thrombolysis, percutaneous coronary intervention, coronary artery bypass surgery, and pacemaker/implantable cardioverter defibrillator insertion, as well as routine intensive care; patients receiving conservative post-resuscitation care (CPRC) served as the other group. The primary and secondary outcomes were survival to discharge and a good neurological outcome (cerebral performance category [CPC] 1–2), respectively. We extracted propensity-matched samples to control for selection bias. A multivariable logistic regression analysis was used to compare the APRC and CPRC groups adjusting for potential risks to calculate the adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs). Of total 64,155 patients, 4557 survived to admission and were included in the final analysis. Out of these patients, 1599 (35.1%) cases survived to discharge, and 499 (11.0%) cases were discharged with good neurological recoveries. Overall, 695 cases (15.3%) received any APRC, including MTH (n = 377, 8.3%) and ACC (370, 8.1%). The outcomes was better in the APRC group than in the CPRC group for survival to discharge (58.7% vs. 30.8%, p < 0.001) and good neurological outcome (27.2% vs. 8.0%, p < 0.001), respectively. In the total cohort, the adjusted ORs of the APRC group compared to those the CPRC group were 2.15 (95% CI 1.78–2.59) for survival to discharge and 2.54 (95% CI 1.98–3.27) for a good neurological outcome. In the propensity score-matched cohort, the adjusted ORs for survival to discharge and good neurological outcome of APRC were significantly favorable.

Conclusions

Active post-resuscitation care resulted in significantly improved outcomes in adult OHCA patients with a presumed cardiac etiology in a nationwide, retrospective, observational study.

Introduction

Out-of-hospital cardiac arrest (OHCA) is a major cause of unexpected deaths worldwide.1 The outcomes of OHCA have been improving thanks to the evidence-based cardiopulmonary resuscitation guidelines followed by numerous clinical and communities’ efforts in the chain of survival,2, 3 while most other outcomes have remained low.1

Post-resuscitation care procedures include more active post-resuscitation care (APRC) procedures, such as mild therapeutic hypothermia (MTH), active cardiac care (ACC) including percutaneous coronary intervention (PCI), coronary artery bypass surgery (CABG), and the insertion of an implantable cardioverter-defibrillator (ICD)/pacemaker (PM), as well as the usual conservative post-resuscitation care (CPRC) procedures, including stabilization of vital signs using vasopressors, ventilation support, general supportive care, glucose control and antiepileptic management.4 Of these procedures, APRC procedures are challenging options in many hospital settings because they require more multidisciplinary approaches and more advanced skills, as well as much greater resources than are required for the usual intensive conservative care for critically ill patients.

In 2003, the American Heart Association issued a guideline recommending that MTH be used to treat cardiac arrest with shockable rhythm,5 and the AHA subsequently incorporated the procedure into its 2005 treatment guidelines,6 such that it finally became the 5th link in the chain of survival that is emphasized in post-cardiac arrest care.4 Active cardiac care, such as with PCI/CABG and ICD/PM, has also been proven to result in better outcomes in OHCA survivors in advanced hospital settings.7, 8

However, a larger proportion of hospitals still prefer to provide only CPRC rather than APRC9, 10, 11 due to unclear indications when selecting treatment options, cultural barriers, lack of interdisciplinary cooperation, lack of resources and knowledge, and cost issues.12, 13 This applies to the current care systems, except for the urban academic medical centers, in Korea. APRC might not be considered as a single treatment option but rather as a multidisciplinary treatment care bundle, which can provide a higher standard care accompanying the procedure itself. There have been few studies on how many patients have been treated, which patients have been treated, and what size of effects has been found with APRC, particularly on a nationwide level.

Post-resuscitation care options are too dynamic and complex, according to patients’ statuses by time period, to implement each protocol or treatment option easily and step by step in clinical practice.4, 14 Hospitals cannot provide treatment options such as MTH or ACC unless there is a dedicated multidisciplinary active post-resuscitation care team with a great amount of experience, skill and resources. A combined procedure (PCI with MTH), as well as each individual procedure, for OHCA was reported to be safe and effective in small case series15, 16 or in a population series.17 Many combinations of treatment options, such as MTH and CABG, MTH with ICD, and PCI followed by PM or ICD, can be considered according to the patient's status. However, combinations can only be chosen by clinicians when they are available. For example, although the clues are very ambiguous for diagnosing ST elevation in MI in a clinical setting, the clinician can choose PCI if he or she has access to additional cardiologic intervention teams in real time. This accessibility can be a proxy measure of organized bundles of post-resuscitation care. Therefore, APRC can be regarded as a proxy of accessibility to a particular comprehensive post-resuscitation care level to a larger extent than can each segmented procedure provided to patients in most other studies.

The objective of this study was to determine the effects of active post-resuscitation care procedures, including MTH and ACC (PCI/CABG, and ICD/PM), on the outcomes of OHCA in a nationwide, population-based OHCA survivor cohort.

Section snippets

Study setting

The Korean emergency medical services (EMS), which is a single-tiered, government-based system, provides a basic-to-intermediate service level of ambulance services from the sixteen provincial headquarters of the national fire department and supports a population of approximately 50 million.18, 19 Ambulance crews can administer CPR at the scene and during transport with automatic external defibrillation and advanced airway management under direct medical control. Advanced cardiac life support is

Demographic findings

Among the 64,155 EMS-assessed OHCA patients with available outcomes, 44,794 adult patients with presumed cardiac etiologies were enrolled after excluding patients with non-cardiac etiologies (n = 17,970) and pediatric (n = 1391) patients. Of these enrollees, 4557 patients survived to admission and were used for the final analysis. There were no patients with a normal alert mental state among the 496 patients (10.9%) receiving ROSC before arriving at the ED. Of these survivors, 1599 (35.1%) cases

Discussion

This study aimed to determine the association between APRC and improved outcomes at the nationwide level. We found the APRC group showed a significantly higher survival to discharge rate (adjusted OR = 2.17) and a good neurological discharge rate in the total cohort (Adjusted OR = 2.54). Significant associations were found in the propensity score-matched cohort.

Previous studies showed a wide variation in the proportion of cases receiving MTH in OHCA. A recent survey study from Italy reported that

Limitations

This study has several limitations to the interpretation of its results and the generalization of these results to other settings. First, this study was not a controlled trial but was a retrospective, observational study. APRC might be selected for patients with a higher likelihood of survival, although we tried to match the risk using propensity scores. Second, the study setting was different from the paramedic level of EMS systems such as those in North American or European communities. A

Conclusion

In this nationwide, observational cohort study, OHCA victims who received any APRC including either MTH or ACC treatment options showed significantly better outcomes than those who only received CPRC. These findings might support the systemic inclusion of the fifth link in the chain of survival to improve the outcomes of OHCA. Prospective studies are needed to strengthen the outcome of APRC.

Conflict of interest statement

No conflicts of interest for all authors are in this study.

Previous presentation

This paper was presented at the National Association of Emergency Medical Services Physician annual congress in January 2011 and at the American Heart Association Resuscitation Science Symposium in Los Angeles in 2012.

Acknowledgement

This study was supported by the National Emergency Management Agency of Korea and the Korean Centers for Disease Control and Prevention. The study was funded by the Korean Centers for Disease Control and Prevention (2008–2011).

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    A Spanish translated version of the summary of this article appears as Appendix in the final online version at http://dx.doi.org/10.1016/j.resuscitation.2013.02.010.

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