Abstract 15: Increasing Compression Rate and Depth Positively Correlate with End-Tidal Carbon Dioxide During Actual CPR Performance

Abstract

Background: Current resuscitation guidelines suggest the use of continuous capnography to monitor the effectiveness of CPR. While laboratory data support this concept, little published clinical data exist to support this recommendation. The quantitative relationship between chest compression (CC) delivery and capnographic measurement (specifically, end-tidal CO 2 (ETCO 2 )) is poorly understood, and has important implications for CPR quality assessment. Objectives: We hypothesized that increasing rate and depth of CC will be associated in real-time with increasing ETCO 2 during both in-hospital cardiac arrest (IHCA) and out-of-hospital cardiac arrest (OHCA). Methods: In a multicenter cohort study, we captured time synchronized ETCO 2 and CPR quality data from resuscitation events at 4 sites between 04/2006 [[Unable to Display Character: –]] 05/2013 using CPR-sensing defibrillators (Philips Mrx-QCPR). ETCO 2 and CC rate and depth were averaged over 15-sec epochs. A linear regression analysis was performed to evaluate the relationship between CCs and ETCO 2 . Results: 29,028 epochs were processed for analysis from 583 arrest events (227 IHCA, 356 OHCA). Average age of the entire cohort was 63.7±17.1 and 213 (37%) were female. ROSC was achieved in 42% of IHCA patients and 27% of OHCA patients. CC rate range was 95-125 per min, CC depth range was 31-59 mm and ventilation rate range was 4-48 per min. CC rate was not significantly associated with ETCO 2 . CC depth was significantly associated with increased ETCO 2 . For every 10 mm increase in depth, ETCO 2 increased by 1.4 mmHg (p<.001). Ventilation rate was inversely related to higher ETCO 2 . For every 10 breaths per min increase in ventilation rate, ETCO 2 was decreased by 3.0 mmHg (p<.001) (see table). Conclusions: ETCO 2 during CPR directly correlated with CC depth, supporting the possible role of capnography as an approach to monitor the quality of CPR delivery. Confounding by ventilation rate may be an important consideration for future work.