Measuring the Call-Receipt-to-Defibrillation Interval: Evaluation of Prehospital Methods,☆☆,

Presented in abstract form at the 88th Annual Scientific Assembly of the Southern Medical Association, Orlando, Florida, November 1994.
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Abstract

Study objective: Successful resuscitation of cardiac arrest depends partly on the time of first defibrillation. An accurate, practical method of measuring this time has not been devised. We attempted to determine the interval from receipt of a call by emergency medical services personnel to first defibrillation (total defibrillation interval) with synchronized clocks between computer-aided dispatch operations and an event-recording defibrillator. Design: A 7-month prospective study measuring the total defibrillation interval. An automated code summary was to be submitted for each participant. Setting: An urban, all–advanced life support, public utility model system. Participants: All primary ventricular fibrillation patients seen during the study period. Results: Ninety-two patients met study criteria. Data are presented as median (interquartile range). The total defibrillation interval was 9.8 minutes (7.9 to 11.8 minutes). The call-receipt–to–vehicle-at-scene interval was 5.98 minutes (4.4 to 7.3 minutes). The vehicle-at-scene–to–defibrillation interval was 3.6 minutes (2.5 to 4.6 minutes). Conclusion: The use of synchronized clocks in automated event-recording systems may provide a method of accurately measuring the time elapsed before defibrillation. [Campbell JP, Kroshus KS, Lindholm DJ, Watson WA: Measurement of the call-receipt–to–defibrillation interval: Evaluation of prehospital methods. Ann Emerg Med December 1995;26:697-701.]

Section snippets

INTRODUCTION

Most cardiac arrests occur outside the hospital.1, 2 Successful cardiac resuscitation depends partly on the interval between cardiac arrest and first defibrillation.3, 4, 5, 6 The total defibrillation interval can be divided methodologically into those subintervals that can be measured and those that have historically been estimated or cannot be accurately determined. Investigators of out-of-hospital cardiac arrests have usually estimated or have not reported the interval from cardiac arrest to

MATERIALS AND METHODS

The study was a 7-month (May–December 1993) prospective evaluation of out-of-hospital response intervals from the point of call receipt by EMS personnel to the time of first defibrillation. We used the LifePak 10 manual external defibrillator (Physio-Control) with automated code summary documentation to measure the time of first defibrillation. From preliminary data, we determined that the clocks of the manual defibrillators lost up to 14 seconds over a 2-week period. Consequently,

RESULTS

Ninety-two of the 324 patients with primary ventricular fibrillation met the study criteria. Two hundred twenty-six were excluded because code summaries were unavailable. Six cases were eliminated because they involved asynchrony of defibrillators and CAD clocks.

The total defibrillation interval was 9.8 minutes (7.9 to 11.8 minutes, Figure 1) for the 92 study patients. The call-receipt–to–vehicle-at-scene interval was 5.98 minutes (4.4 to 7.3 minutes). The vehicle-at-scene–to–defibrillation

DISCUSSION

The goal in treating primary ventricular fibrillation has been to provide prompt defibrillation.3, 4, 5, 13 To shorten the interval from call receipt to defibrillation, various systems have been constructed, including the use of automatic defibrillators by first responders.14, 15 Becker and Pepe16 recently noted that newer, reliable, inexpensive methods that do not interfere with duties at the scene are necessary for many questions about resuscitation efforts to be answered.

Evaluation of the

CONCLUSION

The use of synchronized clocks for automated event recording is a potential method of accurate, practical measurement of the actual time of out-of-hospital defibrillation. Such measurements may aid determination of an accurate call receipt-to-defibrillation interval. Paramedic compliance is necessary for comprehensive information to be gathered. Clock synchronization must be accomplished as the highest priority with this method. In our study, the median interval of EMS call receipt to first

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  • Cited by (12)

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      2009, Heart Rhythm
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      The success of defibrillation and the patient survival rate strongly depend on the duration of VF, dropping 7% to 10% every minute of VF without defibrillation.3 The first defibrillation shock is typically delivered 8 to 12 minutes after emergency call,4 i.e., during long-duration VF (LDVF, duration >1 minute). However, the majority of studies on mechanisms of VF and defibrillation focused on short-duration VF lasting < 1 minute.

    • Public Access Defibrillators and Fire Extinguishers: Are Comparisons Reasonable?

      2008, Progress in Cardiovascular Diseases
      Citation Excerpt :

      A first responder unit must be dispatched, travel to the scene, travel to the patient, assess the situation, and deliver the necessary defibrillation. Campbell et al33 found a call receipt to vehicle at scene time of 5.98 minutes (95% confidence interval [CI], 4.4-7.3 minutes). The vehicle at scene to defibrillation was 3.6 minutes (95% CI, 2.5-4.6 minutes).33

    • Evaluation of duration for direct admission dispatch process in an urban area

      2006, Annales Francaises d'Anesthesie et de Reanimation
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    From the Division of Pharmacy Practice, School of Pharmacy*, and Department of Emergency Medicine, School of Medicine, Truman Medical Center, University of Missouri_Kansas City; and Division of Emergency Medical Services, Department of Health§, Kansas City, Missouri.

    ☆☆

    Address for reprints: Jack P Campbell, MD, FACEP, Department of Emergency Medicine, Truman Medical Center, 2301 Holmes, Kansas City, Missouri 64108, 816-556-3250, Fax 816-881-6282

    Reprint no. 47/1/69548

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