Cardiac arrest & resuscitation
Variations of shock efficacy and refibrillation in different automated external defibrillator (AED) user groups
Authors' conclusion
Across use scenarios, low-energy biphasic shocks were highly effective, independent of shock impedance. Lay and minimally trained responders achieved better shock efficacy and lower refibrillation rates than first responders or EMS, which typically have longer response times. While AMSA correlated with refibrillation, additional factors may also influence AED outcomes.
Study context
- Population
- Adult out-of-hospital cardiac arrest (OHCA) cases treated with low-energy, impedance-compensating biphasic AEDs560 shocked patients · 953 shocks
- Participants
- 2,358 cases
- Exposure
- AED user groups: lay-responder vs trained first-responder vs EMS
- Outcome
- Shock efficacy and refibrillation rate
Methodological detailsUS and Europe
- US and Europe
Main finding
As reported in the abstract
P < 0.001
- Refibrillation rates varied significantly among groups
- P = 0.016
Observational data: associations, not effects.
Further findings
First shock efficacy — Lay-responder vs EMS · across the three groups
P = 0.007
Time to refibrillation (refibrillation within 2 min after successful first shock)
Associations of AMSA and shock impedance
| HR (95 % CI) | ||
|---|---|---|
| Higher AMSARefibrillation; did not fully explain group differences | 0.95 (0.92–0.98) | |
| 0.512Hazard ratio (log scale) |
- Shock impedance not associated with shock efficacy or refibrillation
Original publication
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