Abstract 287: Shock Success Rates with Sternal-apical vs. Anterior-posterior Pad Positioning During Out-of-hospital Cardiac Arrest
Background: Shock success rates for sternal-apical (SA) and anterior-posterior (AP) defibrillator pad positions have not been compared clinically. Houston Fire EMS historically used AP, but changed to SA position, enabling shock success rate comparisons in out-of-hospital cardiac arrest (OHCA) patients.
Methods: Patients treated with manual CPR and biphasic LifePak 500/12 defibrillators (Physio-Control, Redmond, US) were included from January 2006 to April 2007 for AP and from March 2009 to January 2011 for SA, this excluded the transition period when either position may have been used. ECG files were reviewed and initial rhythm, immediate pre-shock and five seconds post-shock rhythms were recorded as shockable or non-shockable. Only indicated shocks were included in analysis of shock success defined as termination of ventricular arrhythmias for at least five seconds. Data were analyzed using SPSS, and differences between the SA and AP groups were calculated using chi-square test and odds ratios (OR).
Results: Of 989 shocked patients, 917 (93%) received 3074 indicated shocks. Of these indicated shocks 1163 of 1436 (81.0%) were successful in 476 SA patients vs. 1303 of 1638 (79.5%) in 441 AP patients (OR 1.10, 95% CI: 0.92-1.31, p=0.32). Median number of indicated shocks was 3 (IQR 1-4) in SA group and 3 (IQR 1-5) in AP group. Initial rhythm was shockable in 269 (57%) SA patients and in 277 (63%) AP patients (p=0.05) with 797 of 993 shocks (80.3%) being successful in this subgroup of SA patients vs. 859 of 1069 (80.4%) in the AP patients (OR 0.99, 95% CI: 0.80-1.24, p=0.96).
Conclusion: There was no significant difference in shock success rate between sternal-apical and anterior-posterior defibrillator pads positioning during manual CPR of OHCA patients.
- © 2013 by American Heart Association, Inc.