Association of National Initiatives to Improve Cardiac Arrest Management With Rates of Bystander Intervention and Patient Survival After Out-of-Hospital Cardiac Arrest

Study Questions:

Out-of-hospital cardiac arrest is a major health problem and it is linked to poor outcomes. Because early recognition and intervention are critical for better outcomes, improving bystander resuscitation attempts may improve survival. Have temporal changes in bystander resuscitation attempts and survival occurred over a 10-year period during which several national initiatives were undertaken to increase bystander resuscitation attempts and improve advanced care?


This study was performed using data from a nationwide Danish Cardiac Arrest Registry. Patients with out-of-hospital cardiac arrest for which resuscitation was attempted were identified between 2001 and 2010, excluding those with noncardiac causes of arrest (n = 7,390) and those with cardiac arrests witnessed by emergency medical services personnel (n = 2,253) where bystander resuscitation was irrelevant. This left a study population of 19,468 patients. Temporal trends in bystander resuscitation and defibrillation, as well as 30-day and 1-year survival were examined.


Patients were older (mean age, 72 years) and mostly men (67%). Bystander resuscitation more than doubled during the study period, rising from 21.1% (95% confidence interval [CI], 18.8%-23.4%) in 2001 to 44.9% (95% CI, 42.6%-47.1%) in 2010 (p < 0.001), whereas bystander defibrillation remained low (1.1% [95% CI, 0.6%-1.9%] in 2001 to 2.2% [95% CI, 1.5%-2.9%] in 2010; p = 0.003). More patients achieved survival on hospital arrival (7.9% [95% CI, 6.4%-9.5%] in 2001 to 21.8% [95% CI, 19.8%-23.8%] in 2010; p < 0.001). Also, 30-day survival improved (3.5% [95% CI, 2.5%-4.5%] in 2001 to 10.8% [95% CI, 9.4%-12.2%] in 2010; p < 0.001) and so did 1-year survival (2.9% [95% CI, 2.0%-3.9%] in 2001 to 10.2% [95% CI, 8.9%-11.6%] in 2010; p < 0.001). Bystander resuscitation also was associated with higher 30-day survival, regardless of witnessed status (30-day survival for nonwitnessed cardiac arrest, 4.3% [95% CI, 3.4%-5.2%] with bystander resuscitation and 1.0% [95% CI, 0.8%-1.3%] without; odds ratio, 4.38 [95% CI, 3.17-6.06]). For witnessed arrest, the corresponding values were 19.4% (95% CI, 18.1%-20.7%) versus 6.1% (95% CI, 5.4%-6.7%); odds ratio, 3.74 (95% CI, 3.26-4.28).


An increase in bystander resuscitation and survival after out-of-hospital cardiac arrest was seen in Denmark between 2001 and 2010.


This is a large population-based epidemiological study of bystander resuscitation and survival following out-of-hospital cardiac arrest. The study is well-done and uses a fairly rigorous data source to capture a large number of patients with these events over a long study period (although some key variables did exhibit high rates of missing values). What I really enjoyed about this article though is the overall balance with which it was written. The authors recognize that this is an ecological analysis; thus, they have been careful not to describe associations they have noted over time between bystander resuscitation and survival as causal. The authors also point out that they are limited in discussing nonmortality outcomes (such as cognitive performance) and have limited data on advanced care that was used (e.g., hypothermia or coronary revascularization). That said, the article is supportive of national efforts in the United States and elsewhere to improve bystander resuscitation, and complements nicely work published last year from the CARES registry (see Sasson C, et al. N Engl J Med 2012). In that provocative paper, bystander resuscitation occurred in approximately 29% of patients with out-of-hospital cardiac arrest from 29 cities across the United States. The odds of undergoing resuscitation varied substantially based on socioeconomic factors and suggest opportunities to target these areas for improvement. This is urgently needed, given the continued poor survival following these events (even in Denmark).

Clinical Topics: Arrhythmias and Clinical EP, Implantable Devices, EP Basic Science, SCD/Ventricular Arrhythmias

Keywords: Complement System Proteins, Octamer Transcription Factor-1, Resuscitation, Emergency Medical Services, Hypothermia, Cardiopulmonary Resuscitation, Denmark, Electric Countershock, Heart Arrest, United States

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