Elsevier

Resuscitation

Volume 72, Issue 2, February 2007, Pages 200-206
Resuscitation

Clinical paper
Epidemiology, trends, and outcome of out-of-hospital cardiac arrest of non-cardiac origin

https://doi.org/10.1016/j.resuscitation.2006.06.040Get rights and content

Summary

Introduction

The majority of victims who experience out-of-hospital cardiac arrest (OHCA) have ventricular fibrillation (VF) as the presenting rhythm and are thought to have a cardiac etiology for their arrest. Over the past decade, the incidence of VF OHCA has declined. The aims of this study were to describe the epidemiology of OHCA of non-cardiac origin in Olmsted County MN and to determine the trends that have occurred over time.

Methods

All residents with a traumatic OHCA from 1995 to 2005 were included for analysis. OHCA data were collected prospectively according to the Utstein method. Cardiac arrests were classified as cardiac or non-cardiac in origin and the etiology determined based on autopsy reports, electronic medical records, and/or emergency medical services reports.

Results

During the study period, 414 OHCAs were identified, 90 (21.7%) of which were classified as non-cardiac. Mean age was 61.5 ± 19.7 years. Response time was 7.73 ± 2.9 min, and 40 (44.4%) were bystander-witnessed. Sixty-eight (75.6%) arrests occurred at home, 13 (14.4%) in a public place, and 9 (10%) in other locations. Bystander CPR was performed in 17 (18.9%) cases. The presenting rhythm was VF in 2 (2.2%) cases, PEA in 54 (60%), and asystole in 34 (37.8%). Eight (8.9%) patients survived to hospital discharge. Respiratory failure (35.6%), unknown (15.6%), and pulmonary embolism (13.3%) were the most common etiologies. The mean percentage of arrests due to a non-cardiac cause in three sequential time-periods (1995–1999, 2000–2002, 2003–2005) was 9.4%, 20.1% and 37.7%, respectively.

Conclusions

Over the study period, 21.7% of OHCAs were non-cardiac in origin. PEA was the most common presenting rhythm and respiratory failure the most common etiology. 8.9% of patients survived. The decreasing number of VF arrests may be a contributing factor to the increasing proportion of OHCAs of non-cardiac etiology observed in the out-of-hospital setting.

Introduction

The majority of victims who experience out-of-hospital cardiac arrest (OHCA) have ventricular fibrillation (VF) as the presenting rhythm and are thought to have a cardiac etiology for their arrest.1, 2 Over the past decade, the incidence of VF OHCA treated by emergency medical services (EMS) personnel has declined.3, 4, 5, 6 The cause of this decline is not clear. It has been suggested that increasing rates of implantable cardiac defibrillator (ICD) placement with ICD termination of ventricular tachycardia or VF may in part account for the decline in VF OHCA.3 It is also likely that primary prevention of coronary artery disease by more aggressive treatment of cardiac risk factors has contributed to the decline.6 Another possibility is that multisystem organ failure is becoming increasingly more common and presenting frequently as non-VF OHCA. Two epidemiological studies of OHCA of non-cardiac etiology have been published.7, 8 This study was designed to provide a description of the epidemiology of OHCA of non-cardiac etiology and to determine the trends that have occurred over time in a city and county in which outcomes from VF OHCA previously have been published.9, 10, 11, 12

Section snippets

Materials and methods

This study was approved by the Mayo Clinic Institutional Review Board for Human Subject Research. All patients with an OHCA between January 1995 and December 2005 who were identified and treated by EMS personnel (police officers/firefighters/paramedics) in our public service area (population in 2004, 133,283) were included. In this EMS system a single advanced life support (ALS) ambulance service responds to all OHCAs, and patients with return of spontaneous circulation (ROSC) are transported

Results

During the study period, 796 OHCAs were considered for resuscitation. In 414 (52%) resuscitation was attempted. Ninety (21.7%) were determined to be of non-cardiac etiology. The non-cardiac etiology was confirmed by autopsy data in 43 (47.8%) cases. In 28 (31.1%), the final diagnosis was determined from both EMS reports and the electronic medical record, and in 19 (21.1%) the diagnosis was determined solely from the EMS record. Forty (44.4%) were bystander witnessed, 17 (18.9%) received BCPR,

Discussion

The majority of victims of OHCA have VF as the presenting rhythm and a cardiac etiology as the cause of their arrest.1, 2 They also are the most frequent survivors. Less attention has been directed to patients who suffer OHCA from a non-cardiac cause. As the incidence of VF arrest continues to decline more and more of these patients are likely to be encountered by EMS.3, 4, 5, 6, 16, 17, 18 The etiologies of non-cardiac arrest are diverse and include respiratory failure, pulmonary embolism,

Conclusions

The incidence of VF as the presenting rhythm in OHCA has been declining over the past decade. Simultaneously, the incidence of non-cardiac cause OHCA has been increasing. Non-cardiac cause OHCA currently constitutes over one-third of all arrests. Respiratory failure, unknown, pulmonary embolism, and drug overdose were the most common etiologies in our community. 8.9% of patients survived to hospital discharge. The decreasing number of VF arrests may be a contributing factor to the increasing

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A Spanish translated version of the summary of this article appears as Appendix in the final online version at 10.1016/j.resuscitation.2006.06.040.

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