Abstract 1812: More CPR with the New Guidelines. Does it Impact VF Termination by Defibrillation Shocks?
The 2005 resuscitation Guidelines emphasize reducing interruptions of cardiopulmonary resuscitation (CPR) and provide changes to the CPR and defibrillation protocols for automated external defibrillator (AED) use. We investigated whether the differences between Guidelines 2000 and 2005 resuscitation protocols influence the ventricular fibrillation (VF) termination rate of AED shocks during out-of-hospital cardiac arrest.
Methods: As part of a clinical trial, VF cardiac arrest patients treated by firefighters were prospectively randomized to treatment protocols consistent with Guidelines 2000 (CONTROL) or Guidelines 2005 (STUDY). The STUDY protocol removed stacked shocks and post-shock pulse checks. It featured 1 minute of CPR before the 1st shock, and CPR between rhythm analysis and shock delivery. All AEDs delivered escalating biphasic shocks beginning at 200J. We reviewed AED electronic records to evaluate VF termination for all shocks within the first 8 minutes of treatment. Successful defibrillation was defined per Guidelines 2005 as termination of VF for > 5seconds. A sample size of 400 shocks per group was prospectively chosen for statistical power to detect an 8% difference in VF termination rate.
Results: As expected, the STUDY protocol resulted in more prompted CPR time, more actual CPR delivered, and fewer shocks during the first 8 minutes of treatment. The VF termination rate did not differ between the two groups (85% CONTROL vs. 87% STUDY). The proportions of patients with ventricular complexes (24% vs. 27%), in asystole (61% vs. 60%), or remaining in a shockable rhythm (15% vs. 13%) at 5 seconds were also not different between the CONTROL and STUDY groups, respectively.
Conclusion: Despite a reduction in CPR hands-off time, VF termination effectiveness of biphasic shocks is similar for Guidelines 2000 and Guidelines 2005 cardiac arrest treatment protocols.