One of the key changes in international resuscitation guidelines between the 2000 and 2005 has been to minimise potentially deleterious hands-off time, so that CPR is interrupted less for pulse checks and DC shocks.
These two approaches have been compared in a randomised controlled trial of 845 patients in France requiring out of hospital defibrillation, in which the control group were shocked using AEDs with prompts based on the 2000 guidelines (3 stacked shocks before CPR resumed, and pulse checks done), and the intervention group were shocked using devices that prompted according to the 2005 guidelines, in which there were fewer and shorter intervals for which the AED required the rescuer to stay clear of the patient (single shocks, no pulse checks).
There was no difference in the primary endpoint of survival to hospital admission (43.2% versus 42.7%; p=0.87), or in survival to hospital discharge (13.3% versus 10.6%; p=0.19). The study was not powered to assess one year survival. In the authors’ words: “our randomized controlled trial now provides more definitive evidence that this combination of Guidelines 2005 CPR protocol changes does not measurably improve outcome. Although the protocol changes accomplish the desired effect of increasing chest compressions, they may also cause other effects, such as earlier refibrillation and more time spent in VF, with as yet unknown consequences.”
Interestingly the Cardio-pump was used in this study to provide chest compressions, which is an active compression-decompression device, potentially limiting the generalisability of the findings to manual compression-only CPR situations. Potential bias was also introduced by the exclusion of patients in whom consent from relatives was not obtained. Nevertheless it’s good to see such rigorous clinical research applied to this area.
DEFI 2005. A Randomized Controlled Trial of the Effect of Automated External Defibrillator Cardiopulmonary Resuscitation Protocol on Outcome From Out-of-Hospital Cardiac Arrest