Figure 12.2 The frame of survival. Source: Nadarajan GD, Tiah L, Ho AFW, et al. Global resuscitation alliance utstein recommendations for developing emergency care systems. Resuscitation 2018;132:85–8. Used with permission of Elsevier.
When callers do not know CPR, the telecommunicator should provide real‐time instructions over the phone. Most current dispatch protocols include detailed, specific CPR instructions [38]. Growing evidence suggests that properly performed chest compressions are more important than ventilations [39–40]. The AHA recommends that bystanders not trained in CPR and those trained but not confident or willing to perform ventilations should perform chest compression‐only CPR until a defibrillator is ready for use [41]. Many emergency dispatch protocols now favor providing instructions only for chest compressions. Unrecognized fatigue is common after just 1‐2 minutes, so bystanders providing chest compressions should switch frequently [42].
Public‐Access Defibrillation
The most important cardiac arrest interventions for patients in VF or VT are early chest compressions and defibrillation. Although 70‐80% of VF can be successfully converted to a perfusing rhythm if shocked within 3 minutes of VF onset, this success rate deteriorates rapidly with each additional minute [43]. Survival decreases 7‐10% for each minute that passes before defibrillation (Figure 12.3) [36].
AEDs
