Resuscitation 86 (2015) 38–43 Contents lists available at ScienceDirect Resuscitation j ourna l ho me pa g e: www.elsevier.com/locate/resuscitation Clinical paper The association between chest compression release velocity and outcomes from out-of-hospital cardiac arrest  Sheldon Cheskes a,b,c,* , Matthew R. Common c,d , Adam P. Byers c , Cathy Zhan c , Annemarie Silver e , Laurie J. Morrison b,c a Sunnybrook Centre for Prehospital Medicine, Toronto, ON, Canada b University of Toronto, Department of Family and Community Medicine, Division of Emergency Medicine, Toronto, ON, Canada c Rescu, Li Ka Shing Knowledge Institute, St. Michaels Hospital, Toronto, ON, Canada d Institute of Medical Science, University of Toronto, Toronto, ON, Canada e Zoll Medical, Chelmsford, MA, United States a r t i c l e i n f o Article history: Received 2 September 2014 Received in revised form 8 October 2014 Accepted 28 October 2014 Keywords: Cardiopulmonary resuscitation Heart arrest Resuscitation Survival a b s t r a c t 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. © 2014 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Improving survival from out-of-hospital cardiac arrest (OHCA) continues to challenge Emergency Medical Services (EMS) systems. 1–3 The 2010 American Heart Association-International Liaison Committee on Resuscitation (AHA-ILCOR) guidelines for cardiopulmonary resuscitation (CPR) suggest improvements in CPR quality may increase the chance of survival from OHCA. 4,5 CPR  A Spanish translated version of the abstract of this article appears as Appendix in the final online version at http://dx.doi.org/10.1016/j.resuscitation.2014.10.020. * Corresponding author at: Sunnybrook Centre for Prehospital Medicine, 77 Brown’s Line, Suite 100, Toronto, ON, Canada M8W 3S2. E-mail address: Sheldon.Cheskes@sunnybrook.ca (S. Cheskes). quality metrics of chest compression fraction (CCF), compression rate, compression depth and peri-shock pause duration have been independently associated with improved survival to hospital discharge from OHCA. 6–10 The importance of minimizing provider leaning on the chest during CPR and allowing for complete chest recoil during chest compressions has been highlighted in an AHA consensus state- ment on CPR quality. 11 Leaning during chest compressions has been associated with both a decrease in venous return and cardiac out- put during CPR. 12 Animal studies have demonstrated deleterious effects on right atrial pressure as well as cerebral and coronary perfusion pressure when leaning occurs during resuscitation. 13,14 These observations suggest that decreasing leaning and improv- ing the speed of chest recoil may improve hemodynamics during cardiac resuscitation. Recent animal studies have suggested that http://dx.doi.org/10.1016/j.resuscitation.2014.10.020 0300-9572/© 2014 Elsevier Ireland Ltd. All rights reserved.