Abstract 50: Time to Defibrillation in Witnessed Out-of-Hospital Cardiac Arrest: Impact on Survival Chances Between Elderly and Younger Patients
Background Guidelines state that with each minute of delay between the onset of an out-of-hospital cardiac arrest (OHCA) and the first defibrillation survival decreases with 3-4% in case of bystander cardiopulmonary resuscitation (CPR), as compared to 7-10% without CPR. Whether this decrease in survival is more pronounced with aging is unknown. We study how survival varies per minute delay between onset of VF and the first defibrillation in general, and the association with age in particular.
Methods Patients with a non-crew witnessed OHCA and VF as presenting rhythm were selected from a 50,000 patient cohort, the prospective Swedish Cardiac Arrest Registry. CPR was performed according to guidelines 2000. Predictors of 1-month survival were assessed according to age (< 70 and ≥ 70 years) and bystander CPR status (yes/no). Interactions between age, bystander CPR, time and 1-month survival were studied.
Results In total 7,158 patients were studied. Bystander CPR was provided in 48% and 1-month survival was 11% (n=772). Independent predictors of survival were age, time from cardiac arrest to bystander CPR and from cardiac arrest to first defibrillation. Per minute delay to defibrillation, the decrease in survival was 11.6% (9.9-13.3%) in patients with bystander CPR and 17.1% (14.1-20.0%) in patients without bystander CPR. For patients < 70 years with bystander CPR the decrease in survival per minute delay was 12.8% (10.6-15.0%) versus 9.9% (7.3-12.4%) for patients ≥ 70 years. Without bystander CPR the decrease in survival per minute delay for patients < 70 and ≥ 70 years was 14.9% (10.6-19.0%) and 19.2% (14.9-23.3%) respectively. No interactions between age, time from cardiac arrest to defibrillation and survival were found.
Conclusion In this large prospective registry, the relative decrease in survival per minute delay until defibrillation is 10 to 20%, for cases with and without bystander CPR respectively. These figures are much higher than the reported delays in the guidelines, based upon smaller studies. The observed relative decrease in survival per minute delay to first defibrillation did not differ between younger patients and the elderly. Future studies should address these questions for resuscitation according to the 2010 guidelines.
- © 2012 by American Heart Association, Inc.