Aim: To determine whether in patients with an ambulance response time of >5min who were in VF cardiac arrest, 3min of CPR before the first defibrillation was more effective than immediate defibrillation in improving survival to hospital discharge.
Methods: This randomised control trial was run by the South Australian Ambulance Service between 1 July, 2005, and 31 July, 2007. Patients in VF arrest were eligible for randomisation. Exclusion criteria were: (i) <18 years of age, (ii) traumatic arrest, (iii) paramedic witnessed arrest, (iv) advanced life support performed before arrival of paramedics and (v) not for resuscitation order or similar directive. The primary outcome was survival to hospital discharge with secondary outcomes being neurological status at discharge, the rate of return of spontaneous circulation (ROSC) and the time from first defibrillation to ROSC.
Results: For all response times, no differences were observed between the immediate defibrillation group and the CPR first group in survival to hospital discharge (17.1% [18/105] vs. 10.3% [10/97]; P=0.16), the rate of ROSC (53.3% [56/105] vs. 50.5% [49/97]; P=0.69) or the time from the first defibrillation to ROSC (12:37 vs. 11:19; P=0.49). There were also no differences between the immediate defibrillation group and the CPR first group, for response times of < or = or > 5min: survival to hospital discharge (50.0% [7/14] vs. 25.0% [4/16]; P=0.16 or 12.1% [11/91] vs.7.4% [6/81]; P=0.31, respectively) and the rate of ROSC (71.4% [10/14] vs. 75.0% [12/16]; P=0.83 or 50.5% [46/91] vs. 45.7% [37/81]; P=0.54, respectively). No differences were observed in the neurological status of those surviving to hospital discharge.
Conclusion: For patient in out-of-hospital VF cardiac arrest we found no evidence to support the use of 3min of CPR before the first defibrillation over the accepted practice of immediate defibrillation.