Abstract 295: Time in CPR Is Significantly Related to CPR Quality and Survival
Background: Total CPR time and CPR quality are both believed to be associated with survival; however the exact relationship is unclear.
Objectives: To assess the relationship between time in CPR and CPR quality for OHCA and survival to discharge. Our hypothesis was that time in CPR is both an independent predictor of mortality and a significant confounder of CPR quality and survival.
Methods: CPR quality metrics were measured using an E Series defibrillator (ZOLL Medical) during the treatment of consecutive OHCA patients in a large urban EMS system from 9/2008-6/2013. Non-EMS witnessed adult (>18 years) arrests of presumed cardiac etiology were included. We used multivariable logistic regression (LR) to assess the relationship between time in CPR and its association with various CPR quality metrics [chest compressions (CC) depth, CC rate, CC recoil velocity (RV), CC fraction] and survival, adjusting for other known risk factors and confounders (age, sex, use of therapeutic hypothermia, witnessed arrest, shockable rhythm, location of OHCA). Time in CPR was considered a significant confounder of CPR quality metrics and survival if inclusion of time in CPR in LR models changed the regression coefficients for a CPR quality metrics by 10% or more.
Results: Time in CPR was a significant independent predictor of survival (adjusted OR: 0.80; 95% CI: 0.75-0.84), with each minute leading to a 20% decrease in the odds of survival. Time in CPR was a significant confounder of the relationship between survival and the following CPR quality metrics: CC RV (change in coefficient = -26%), CC rate (change = 44%), CC fraction (change = 57%), CC depth (change =11.4%). Both the percentage of CC above 51mm (adjusted OR per 10% increase = 1.15, 95%CI: 1.02- 1.31) and CC RV above 400 mm/s (adjusted OR = 3.53, 95% CI: 1.28-9.76) were significantly associated with survival for cases with time in CPR less than 15 minutes but neither was associated with survival in cases with time in CPR 15 minutes or more (p>0.8).
Conclusions: Time in CPR was significantly associated with lower survival from OHCA and was a significant confounder for four CPR quality metrics (CC depth, RV, fraction, rate). Time in CPR should be accounted for in studies assessing the impact of CPR quality on outcomes.
Author Disclosures: U. Stolz: None. T. Irisawa: None. H. Ryoo: None. A. Silver: Employment; Significant; ZOLL Medical Corporation. R. McDannold: None. J. Jaber: None. B. Bobrow: Research Grant; Significant; Medtronic Foundation. D. Spaite: Research Grant; Significant; Medtronic Foundation.
- © 2014 by American Heart Association, Inc.