Are two shocks better than one? Aotearoa New Zealand emergency medical services implement a new defibrillation strategy: implications for around nine patients per week

Aotearoa New Zealand emergency medical services (EMS) began routinely using new external defibrillation strategies for the treatment of refractory ventricular fibrillation (VF) and pulseless ventricular tachycardia (VT) from January 2024. These strategies are vector change (VC) defibrillation and double sequential external defibrillation (DSED). DSED provides rapid sequential shocks using two defibrillators with the pads attached in two different vectors, one in an anterior-lateral and the other in an anterior- posterior position. Around 20% of patients with ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT) do not respond to three or more single defibrillation attempts (i.e., are in refractory VF/VT) and have lower survival rates than those who respond to standard (single defibrillation every two minutes) resuscitation approaches. Consideration of DSED and VC defibrillation (switching defibrillation pads from anterior-lateral to an anterior-posterior position) has been suggested for these patients in the 2023 update of the International Consensus on Cardiopulmonary Resuscitation (ILCOR) and Emergency Cardiovascular Care Science with Treatment Recommendations.