AED Defibrillation
AED Defibrillation
All trained BLS responders must know how to use an automated external defibrillator (AED). It has been shown that outcomes are improved when an AED delivers a shock to defibrillate the shockable cardiac arrest rhythms, especially if CPR and defibrillation are provided within 3 to 5 minutes of collapse. 22 Because of these findings, rapid defibrillation is the treatment of choice for witnessed OHCA patients with VF or hospitalized patients in cardiac arrest.
Related Video: How to Use an Automated External Defibrillator (AED) Safely
Principles of Defibrillation
Once available, defibrillation should be used immediately for a witnessed adult with cardiac arrest. While waiting for the AED to arrive, the rescuers provide chest compressions. If the AED is already available, rescuers can apply it immediately and deliver a shock if warranted.
For more than one rescuer, one will provide chest compressions while the other rescuer is setting up the AED. After delivering the shock, 2 minutes of continuous, high-quality chest compressions should ensue.
A lone rescuer must apply the AED at once and deliver the shock. Following the shock sequence, 2 minutes of high-quality CPR with a 30:2 compression-to-ventilation ratio should be given before performing the next rhythm check.
Studies have shown there is no benefit from performing CPR before attempted defibrillation. 23
Rhythm Analysis During Compressions
If possible, cardiac rhythms should be monitored while performing chest compressions. However, due to motion artifacts, chest compressions must be stopped to ensure an accurate reading.
Timing of Rhythm Check
As recommended, high-quality chest compressions should immediately resume after the AED has delivered a shock. Studies have shown improvement in survival and neurologic outcomes with bundled care that includes the resumption of chest compressions immediately after shock delivery. 24
The rhythm is checked again only after a full cycle of 2 minutes of chest compressions and ventilations.
22 Sasson C, Rogers MAM, Dahl J, Kellermann AL. Predictors of survival from out-of-hospital cardiac arrest: a systematic review and meta-analysis. Circ Cardiovasc Qual Outcomes. 2010;3(1):63–81.
https://www.ahajournals.org/doi/full/10.1161/circoutcomes.109.889576
23 Wik L, Hansen TB, Fylling F, et al. Delaying defibrillation to give basic cardiopulmonary resuscitation to patients with out-of-hospital ventricular fibrillation: a randomized trial. JAMA. 2003;289(11):1389–1395.
24 Bobrow BJ, Clark LL, Ewy GA, et al. Minimally interrupted cardiac resuscitation by emergency medical services for out-of-hospital cardiac arrest. JAMA. 2008;299(10):1158–1165.