The association between chest compression release velocity and outcomes from out-of-hospital cardiac arrest

Background: Previous studies have demonstrated significant relationships between cardiopulmonary resuscitation (CPR) quality metrics and survival to hospital discharge from out-of-hospital cardiac arrest (OHCA). Recently, it has been suggested that a new metric, chest compression release velocity (CCRV), may be associated with improved survival from OHCA. Methods and results: We performed a retrospective review of all treated adult OHCA occurring over a two year period beginning January 1, 2012. CPR metrics were abstracted from accelerometer measurements during each resuscitation. Multivariable regression analysis was used to examine the impact of CCRV on survival to hospital discharge. Secondary outcome measures were the impact of CCRV on return of spontaneous circulation (ROSC) and neurologically intact survival (MRS <= 3). Among 1800 treated OHCA, 1137 met inclusion criteria. The median (IQR) age was 71.6 (60.6, 82.3) with 724 (64%) being male. The median (IQR) CCRV (mm/s) amongst 96 survivors was 334.5 (300.0, 383.2) compared to 304.0 (262.6, 354.1) in 1041 non survivors (p < 0.001). When adjusted for Utstein variables, the odds of survival to hospital discharge for each 10 mm/s increase in CCRV was 1.02 (95% CI: 0.98, 1.06). Similarly the odds of ROSC and neurologically intact survival were 1.01 (95% CI: 0.99, 1.03) and 1.02 (95% CI: 0.98, 1.06), respectively. Conclusions: When adjusted for Utstein variables, CCRV was not significantly associated with outcomes from OHCA. Further research in other EMS systems is required to clarify the potential impact of this variable on OHCA survival. (C) 2014 Elsevier Ireland Ltd. All rights reserved.