title: Improved neurological outcome with continuous chest compressions compared with 30:2 compressions-to-ventilations cardiopulmonary resuscitation in a realistic swine model of out-of-hospital cardiac arrest.
abstract: BACKGROUND
  The 2005 Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care changed the previous ventilations-to-chest-compression algorithm for bystander cardiopulmonary resuscitation (CPR) from 2 ventilations before each 15 chest compressions (2:15 CPR) to 30 chest compressions before 2 ventilations (30:2 CPR). It was acknowledged in the guidelines that the change was based on a consensus rather than clear evidence. This study was designed to compare 24-hour neurologically normal survival between the initial applications of continuous chest compressions without assisted ventilations with 30:2 CPR in a swine model of witnessed out-of-hospital ventricular fibrillation cardiac arrest.
  
  
  RESULTS
  Sixty-four animals underwent 12 minutes of ventricular fibrillation before defibrillation attempts. They were divided into 4 groups, each with increasing durations (3, 4, 5, and 6 minutes, respectively) of untreated ventricular fibrillation before the initiation of bystander resuscitation consisting of either continuous chest compression or 30:2 CPR. After the various untreated ventricular durations plus bystander resuscitation durations, all animals were given the first defibrillation attempt 12 minutes after the induction of ventricular fibrillation, followed by the 2005 guideline-recommended advanced cardiac life support. Neurologically normal survival at 24 hours after resuscitation was observed in 23 of 33 (70%) of the animals in the continuous chest compression groups but in only 13 of 31 (42%) of the 30:2 CPR groups (P=0.025).
  
  
  CONCLUSIONS
  In a realistic model of out-of-hospital ventricular fibrillation cardiac arrest, initial bystander administration of continuous chest compressions without assisted ventilations resulted in significantly better 24-hour postresuscitation neurologically normal survival than did the initial bystander administration of 2005 guideline-recommended 30:2 CPR.
authors.affiliation: University of Arizona Sarver Heart Center, University of Arizona College of Medicine, Tucson AZ 85724, USA. gaewy@aol.com
authors.forename: Gordon A
authors.initials: GA
authors.lastname: Ewy
authors.forename: Mathias
authors.initials: M
authors.lastname: Zuercher
authors.forename: Ronald W
authors.initials: RW
authors.lastname: Hilwig
authors.forename: Arthur B
authors.initials: AB
authors.lastname: Sanders
authors.forename: Robert A
authors.initials: RA
authors.lastname: Berg
authors.forename: Charles W
authors.initials: CW
authors.lastname: Otto
authors.forename: Melinda M
authors.initials: MM
authors.lastname: Hayes
authors.forename: Karl B
authors.initials: KB
authors.lastname: Kern
mesh_terms: D000818:Animals; D016887:Cardiopulmonary Resuscitation / Q000379:methods* / Q000401:mortality / Q000592:standards; D006323:Heart Arrest / Q000150:complications / Q000401:mortality / Q000628:therapy*; D006336:Heart Massage / Q000379:methods* / Q000592:standards; D023421:Models, Animal; D009422:Nervous System Diseases / Q000209:etiology; D017410:Practice Guidelines as Topic / Q000592:standards*; D013552:Swine; D016896:Treatment Outcome; D014693:Ventricular Fibrillation / Q000150:complications / Q000401:mortality / Q000628:therapy