Cardiac ArrestInterruption of cardiopulmonary resuscitation with the use of the automated external defibrillator in out-of-hospital cardiac arrest☆
Introduction
Improvement in survival of patients experiencing out-of-hospital cardiac arrest is possible in some settings by the use of the automated external defibrillator by first responders. This benefit is greatest in patients in ventricular fibrillation who receive their first shock within 5 minutes after the call.1, 2, 3, 4 The importance of rapid delivery of the first shock for patients in ventricular fibrillation is well known,5, 6 as is the importance of early cardiopulmonary resuscitation (CPR).7, 8, 9
Animal models have demonstrated that interruption of chest compression and ventilation before shock delivery compromises survival.10, 11 Research in pigs has shown that interruptions of precordial compression for rhythm analysis that exceed 15 seconds before each shock delivery compromise the outcome of the resuscitation and increase the severity of postresuscitation myocardial dysfunction. An investigation in rats demonstrated that, when CPR was interrupted for 40 seconds before shock delivery, no animal could be resuscitated successfully.
Protocols for automated external defibrillator use call for “hands-off” time, during which no CPR can be performed. They also call for rescuers to check for a pulse or signs of circulation during the resuscitation attempts. The duration of these interruptions in the various phases of the CPR–automated external defibrillator procedure has not yet been reported. This study assessed the actual interruption time of CPR during the use of automated external defibrillators in patients experiencing out-of-hospital cardiac arrest when resuscitated by first responders.
Section snippets
Methods
This is a prospective, observational study initiated and measured to describe CPR interruption during the use of automated external defibrillators by first responders. Between January 2000 and April 2002, we included all victims of out-of-hospital cardiac arrest in Amsterdam, The Netherlands, and its vicinity for which first responders applied an automated external defibrillator.
Police and fire brigades served as first responders with an automated external defibrillator in Amsterdam and a large
Results
From January 2000 to March 2002, 187 recordings of automated external defibrillator use were collected. Of these, 184 (98%) could be analyzed. In 2 recordings, no sound had been recorded, and in 1 the ECG registration was not continuous for technical reasons. The baseline characteristics of the patients and the process characteristics are listed in Table 1. The Utstein survival data are shown in Figure 2.
In 72% of the recordings, the start and end times of the CPR periods could be determined
Discussion
This study demonstrated that, during real resuscitation attempts, for more than half the time the automated external defibrillator was connected, no CPR was being performed. In patients with shockable initial rhythm, CPR was absent 63% of the time the automated external defibrillator was connected because of programmed instructions and performance of first responders. In patients with a nonshockable rhythm, CPR was absent during 46% of automated external defibrillator connection.
Animal and
Acknowledgements
We appreciate the assistance of Medtronic Physio-Control (United States), Laerdal (Benelux), and Cardiac Science (The Netherlands), who made the LIFEPAK 500, the Heartstart FR2, and the Survivalink available for analysis of voice prompts.
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Editor's note: This article was first published on Annals Web site (www.mosby.com/AnnEmergMed) on July 8, 2003. Articles of particular interest are published on the Web site in advance of their appearance in the print journal. In the future, an increasing percentage of our content will be published first on the Web, predating the print publication as a service to our readers.
Author contributions: APvA and RWK conceived the study and supervised the data collection. BTS performed the data collection and analyzed the data. APvA drafted the manuscript. All authors contributed substantially to its revisions. RWK takes responsibility for the paper as whole.
This study was supported by a grant from The Netherlands Heart Foundation (grant 98.179)
Reprints not available from the authors.