title: Measuring the call-receipt-to-defibrillation interval: evaluation of prehospital methods.
abstract: 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.
  
  
  METHODS
  A 7-month prospective study measuring the total defibrillation interval. An automated code summary was to be submitted for each participant.
  
  
  METHODS
  An urban, all-advanced life support, public utility model system.
  
  
  METHODS
  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).
  
  
  CONCLUSIONS
  The use of synchronized clocks in automated event-recording systems may provide a method of accurately measuring the time elapsed before defibrillation.
mesh_terms: D004554:Electric Countershock; D004632:Emergency Medical Services; D006302:Health Services Research / Q000379:methods; D006323:Heart Arrest / Q000209:etiology / Q000628:therapy*; D006801:Humans; D011446:Prospective Studies; D013997:Time Factors; D019037:Urban Health Services; D014693:Ventricular Fibrillation / Q000150:complications / Q000628:therapy*