Mr Jason Belcher1,2, Dr David Majewski2, Dr Milena Talikowska2, Dr Stephen Ball2,1, Dr Sarah Harris2, Mr Andrew Bell1,2, Prof. Judith Finn2,1
1St John WA, Belmont, Australia, 2Curtin University, Perth, Australia
Biography:
Prof Judith Finn is Director of the Prehospital, Resuscitation & Emergency Care Research Unit (PRECRU) in the Curtin School of Nursing, Perth, WA – St John WA being PRECRU’s principal research parter. Judith (critical care registered nurse and epidemiologist) was the inaugural Director of the Australasian Resuscitation Outcomes Consortium (Aus-ROC).
Abstract:
Introduction
In 2023, St John Western Australia introduced double sequential defibrillation (DSED) for refractory ventricular fibrillation unresponsive to antiarrhythmics and vector change defibrillation. Of consideration is that the preparation and on-scene safety briefing before DSED may distract from CPR quality and that dual defibrillator discharge may increase peri-shock pause. This study examined the impact of DSED on CPR metrics and peri-shock pause.
Methods
DSED cases were identified from the St John WA out-of-hospital cardiac arrest database. Linear mixed-effects models compared CPR metrics for the CPR cycle immediately before the first DSED shock against all preceding cycles. Metrics were compression fraction, and the percentage of compressions at target rate (100–120 cpm) and target depth (>5 cm). Peri-shock pause for DSED shocks was similarly compared against preceding single shocks.
Results
Of 34 DSED cases, nine were excluded (three lacking monitor data, six with mechanical CPR), leaving 25 for analysis. Point estimates for compression fraction (0.6% higher, 95% CI -4.1 – 5.4%), percentage of compressions at target rate (3.6% higher, 95% CI -2.7 – 9.9%), and at target depth (6.8% higher, 95% CI -2.7 – 16.2%) showed modest improvements, with wide confidence intervals reflecting the small sample. Peri-shock pause was 2.2 seconds longer for DSED shocks (95% CI -0.5 – 4.9s).
Conclusions
This pilot suggests DSED can be performed without substantial impact on CPR metrics during DSED preparation. Peri-shock pause was 2.2-seconds longer for DSED shocks; an increase of this magnitude may be clinically meaningful, though precision is limited by sample size.