Elsevier

Resuscitation

Volume 81, Issue 4, April 2010, Pages 422-426
Resuscitation

Clinical paper
Improving outcome after out-of-hospital cardiac arrest by strengthening weak links of the local Chain of Survival; quality of advanced life support and post-resuscitation care

https://doi.org/10.1016/j.resuscitation.2009.12.020Get rights and content

Abstract

Background

Survival after out-of-hospital cardiac arrest (OHCA) depends on a well functioning Chain of Survival. We wanted to assess if targeted attempts to strengthen the weak links of our local chain; quality of advanced life support (ALS) and post-resuscitation care, would improve outcome.

Materials and methods

Utstein data from all OHCAs in Oslo during three distinct 2-year time periods 1996–1998, 2001–2003 and 2004–2005 were collected. Before the second period the local ALS guidelines changed with increased focus on good quality chest compressions with minimal pauses, while standardized post-resuscitation care including goal directed therapy with therapeutic hypothermia and percutaneous coronary intervention was added in the third period. Additional a priori sub-group analyses of arrests with cardiac aetiology as well as bystander witnessed ventricular fibrillation/tachycardia (VF/VT) arrests with cardiac aetiology were performed.

Results

ALS was attempted in 454, 449, and 417 patients with OHCA in the first, second and last time period, respectively. From the first to the third period VF/VT arrests declined (40% vs. 33%, p = 0.039) and fewer arrests were witnessed (80% vs. 72%, p = 0.022) and response intervals increased (7 ± 4 to 9 ± 4 min, p < 0.001). Overall survival increased from 7% (first period) to 13% (last period), p = 0.002, and survival in the sub-group of bystander witnessed VF/VT arrests with cardiac aetiology increased from 15% (first period) to 35% (last period), p = 0.001.

Conclusions

Survival after OHCA was increased after improving weak links of our local Chain of Survival, quality of ALS and post-resuscitation care.

Introduction

Guidelines for cardiopulmonary resuscitation are developed in order to improve survival after cardiac arrest. Despite evolving evidence-based guidelines for cardiopulmonary resuscitation (CPR),1, 2 survival rates after out-of-hospital cardiac arrest (OHCA) has not improved much.3, 4 The Chain of Survival concept of early access, early CPR, early defibrillation and good post-resuscitation care is the documented and recommended guide for improving outcome after OHCA.1, 2, 5 Documenting Utstein data for OHCA is a useful tool for evaluating and critically assessing the local Chain of Survival in an emergency medical service (EMS), identifying areas in need of improvement in order to increase survival after OHCA.6

In Oslo, Norway, survival to hospital discharge for OHCA of cardiac aetiology has been below 10% for the last 30 years.7, 8, 9 In the time period from 1996 to 1998 the ALS providers in the Oslo EMS were trained according to 1992 guidelines,10 resulting in poor ALS quality with long periods without vital organ perfusion and few shocks resulting in return of spontaneous circulation (ROSC).8 In 2001 the 2000 international guidelines11, 12 were implemented with a modification consisting of increased focus on chest compression quality including 3 min periods of CPR before and between defibrillations, based on findings from local ALS studies.8, 13 The main aim of these changes was to optimize vital organ perfusion by minimizing interruptions in chest compression and more reasonable timing of defibrillations,14 defined as improving the third link in our local Chain of Survival. A standardized post-resuscitation treatment protocol including therapeutic hypothermia and percutaneous coronary intervention (PCI) was implemented in 2003 to strengthen the last link.15

Through implementation of new and modified guidelines and evolving scientific evidence, our local Chain of Survival was thereby changed throughout this 9-year period, with special focus on the last two links. The first period (1996–1998) had poor ALS quality and post-resuscitation care, the second period (2001–2003) had good ALS quality but poor post-resuscitation care, and the third period (2004–2005) had both good ALS quality and post-resuscitation care. In the present study we wanted to evaluate if these temporal changes strengthened our local Chain of Survival and impacted on outcome after OHCA.

Section snippets

Description of Oslo

The city of Oslo covers 454 km2 and has 548,617 inhabitants (January 1st 2007) with 51% female population and 4.4% of the population over 80 years. Oslo has had a continuous population growth the last 20 years, mainly due to migration leading to a larger proportion of young adults 20–39 and lower proportion of children and adults >40 years compared to the rest of the country.16

Description of EMS and in-hospital treatment

The city of Oslo has a one-tiered community run EMS system. All acute care ambulances are manned with paramedics. On

Results

During the three study periods, altogether 1320 patients received ALS for OHCA. The Utstein style results from the three study periods are reported in Table 1.

Discussion

Despite an increase in negative prognostic factors such as more unwitnessed non-VF arrests and increased response intervals, outcome was significantly improved during our 9-year study period. The greatest improvements in survival were seen in bystander witnessed VF/VT arrests of cardiac origin, which may be considered the most homogenous and therefore easiest comparable group of patients within the cardiac arrest population.6 Continuous focus on the importance of a well functioning Chain of

Conclusion

The increasing proportion of survivors with favourable neurological outcome, both overall and for all sub-groups, indicates that the strengthening of the last two links in our local Chain of Survival has lead to significantly improved outcome for patients with out-of-hospital cardiac arrest.

Contributions

Lund-Kordahl and Olasveengen have full access to all generated data and take full responsibility for the integrity of the data and the accuracy of the data analysis. Olasveengen and Sunde have contributed to the concept and design of the study. Acquisition of data was performed by Wik, Lund-Kordahl and Lorem. Analysis and interpretation of the data were done by Lund-Kordahl, Olasveengen and Sunde. Lund-Kordahl, Olasveengen and Sunde have drafted the manuscript. Critical revision of the

Financial support

The study was supported by grants from Eastern Norway Regional Health Authority, Oslo University Hospital Ulleval, Norwegian Air Ambulance Foundation, Laerdal Foundation for Acute Medicine, Anders Jahres Fund.

Conflict of interest statement

Olasveengen has received honoraria from Medtronic (Oslo, Norway) and research support from Laerdal Medical Corporation (Stavanger, Norway). Wik is on a Medical Advisory Board for Physio-Control, has in the past consulted for Physio-Control, Zoll, Laerdal and Jolife, and is the principle investigator for a multi-centre mechanical chest compression device study sponsored by Zoll. Lund-Kordahl, Lorem, Samdal and Sunde have no conflicts to declare.

Acknowledgements

We thank all physicians and paramedics working in the Oslo EMS Service as well as Ståle Nygård for assistance with the statistics and Petter Andreas Steen for invaluable help in preparing the manuscript. The study was supported by grants from Eastern Norway Regional Health Authority, Ulleval University Hospital, Norwegian Air Ambulance Foundation, Laerdal Foundation for Acute Medicine, and Anders Jahres Fund.

References (35)

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    Coordinated efforts targeted at improving the local chain of survival have improved regional survival.49,50 Targeted approaches to improve the effectiveness of CPR have resulted in positive outcomes.52-54 The group most likely to survive an OHCA is persons who are witnessed to collapse by a bystander and found in a shockable rhythm, so widespread CPR training is recommended.

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A Spanish translated version of the abstract of this article appears as Appendix in the final online version at doi:10.1016/j.resuscitation.2009.12.020.

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