High Discharge Survival Rate After Out-of-Hospital Ventricular Fibrillation With Rapid Defibrillation by Police and Paramedics☆,☆☆,★
Section snippets
INTRODUCTION
Rapid defibrillation after out-of-hospital cardiac arrest (OHCA) caused by ventricular fibrillation (VF) is the single most important determinant of outcome.1, 2 Other variables such as witnessed arrest, rapid access to emergency medical services (EMS), prompt bystander CPR, and initial VF maximum amplitude have been shown to improve survival.3, 4, 5, 6, 7, 8, 9, 10 However, the interval between collapse and delivery of defibrillatory shocks is the most critical variable influencing outcome.1
MATERIALS AND METHODS
The city of Rochester, Minnesota (1993 population, 76,865; area, 32.6 square miles), is served by a private ambulance service (Gold Cross Ambulance Service, Incorporated). Patient care personnel are nationally registered EMT-Ps. Rochester Police Department police officers are trained as first responders in accord with the US Department of Transportation First Responder Training Program.23 All officers are trained to operate automated external defibrillators (AEDs) with the American Heart
RESULTS
During the 57-month study period, 84 OHCA patients presented with VF as the initial rhythm. Seventy-four patients in non-VF arrest (40 in asystole and 34 in pulseless electrical activity) were encountered but were excluded from this analysis for obvious reasons. All arrests included in the study occurred before the arrival of police or paramedics. None of the 74 survived. No patients were excluded because of insufficient, inaccurate, or unavailable data.
Thirty-one patients were first shocked by
DISCUSSION
Our observations extend and affirm the conclusions of our earlier preliminary study.22 In that study, as in this one, we chose to use the call-to-shock interval rather than the collapse-to-shock interval because the latter is almost always, at best, an estimate. We prefer to use an interval that is precise and quantitative and can be correlated with outcome. The call-to-shock interval also can be used for accurate intersystem data comparisons, provided all EMS system clocks are synchronized at
Acknowledgements
The authors are grateful to Kimberly Sankey for assistance in preparation of the manuscript; to Elizabeth Atkinson, Section of Biostatistics, Mayo Clinic; to the City of Rochester Police Department; to Gold Cross Ambulance Service personnel; and to law enforcement and Gold Cross dispatch staff for their commitment to synchronization of times.
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Cited by (0)
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From the Mayo Clinic and Medical School* and May Gold Cross Ambulance Service, Incorporated‡, Rochester, Minnesota; and the Affiliated Residency in Emergency Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.§
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Address for reprints: Roger D White, MD, Department of Anesthesiology, Mayo Clinic, 200 First Street Southwest, Rochester, Minnesota 55905, 507-255-4235, Fax 507-255-6463, E-mail [email protected]
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Reprint no. 47/1/76895