Abstract 256: Accuracy of Manual Shock by Paramedics
Background: Limited data exist on the accuracy of rhythm interpretation and manual shocks during out-of-hospital cardiac arrest (OHCA). A prior study, based on data collected before the advent of contemporary high-performance CPR, reported that 21% of manual shocks by paramedics during OHCA were inappropriately delivered to non-shockable rhythms. The current emphasis on minimizing pre-shock pause can reduce the time available for an accurate rhythm determination, and thus might increase inappropriate shocks. We sought to characterize inappropriate shocks in a paramedic service after adoption of high-performance CPR aimed at limiting pre-shock pauses.
Methods: We analyzed defibrillator records from all OHCA cases from 10/2009 to 12/2012 in an EMS system providing care for a community of 270,000 persons. Three paramedics independently reviewed continuous ECG and impedance data from all cases with at least one manual shock to assess pre-shock rhythm and categorize each shock as appropriate, inappropriate, or indeterminate. We then characterized inappropriate shocks with respect to OHCA circumstances and pre-shock pause duration.
Results: Of 316 individual shocks in 88 analyzed cases, 286 (90.5%) shocks were classified as appropriate, 28 (8.9%) inappropriate, and 2 indeterminate. A majority of inappropriate shocks (18 of 28; 64%) clustered among 7 (8%) cases with ≥ 2 inappropriate shocks. Median pre-shock pause did not differ significantly between inappropriate (4 [3, 7] sec) and appropriate shocks (5 [3, 9] sec, p=0.47). For all inappropriate shocks, pre- and post-shock rhythms were the same. Median compression fraction was similar for inappropriate shock (0.93 [0.92, 0.95]) vs. appropriate shock cases (0.91 [0.88, 0.94]; p=0.06). Patients receiving inappropriate vs. appropriate shocks did not differ significantly in age, gender, time-of-day of arrest, or attainment of ROSC.
Conclusions: In this observational cohort, inappropriate manual shocks were infrequent and clustered in a small subset of cases. Pre-shock pause was short and not associated with appropriateness of manual shock delivery. Compared to prior reports, these results suggest that paramedics can provide appropriate manual shocks in the setting of high-performance CPR.
- Cardiac arrest
- Cardiopulmonary resuscitation
- Advanced life support
- Arrhythmias, treatment of
Author Disclosures: D.A. Yost: Consultant/Advisory Board; Modest; Resurgent Biomedical Consulting. A. Moorhead: None. J. Whitney: None. A. Whorton: None. R.G. Walker: Employment; Significant; Employed by Physio-Control.
- © 2014 by American Heart Association, Inc.