Abstract 1806: End-tidal Carbon Dioxide as a Measure of Cardiopulmonary Resuscitation Efficacy during Human Cardiac Arrest
Background: End-tidal carbon dioxide (EtCO2) is a physiologic measure that has potential to serve as an indicator of chest compression efficacy, with higher EtCO2 values during CPR correlating with improved hemodynamics during prior laboratory studies. EtCO2 measurement could therefore guide resuscitation efforts and help optimize CPR performance.
Objective: To test the hypothesis that EtCO2 levels positively correlate with improved chest compression rate and depth during human cardiac arrest.
Methods: A prospective, observational study was conducted using a commercially available monitor/defibrillator with CPR quality and EtCO2 sensing capabilities (MRx-QCPR, Philips Medical Systems) during in-hospital cardiac arrests at one hospital from 4/2006 until 8/2006. Resuscitation transcripts were divided into 30-second segments and mean values of chest compression rate and depth and EtCO2 were derived for each segment. Regression analysis, with cluster-adjustment for individual patients, was used to correlate compression rate and depth with EtCO2.
Results: Data were collected and analyzed from 281 30-second segments with a median of 12 (interquartile range: 8–33) segments per arrest from 13 consecutive patients for whom EtCO2 and chest compression data were simultaneously available. Mean EtCO2 was 19±7 mmHg. After adjusting for compression rate and clustering, there was a positive correlation between compression depth and EtCO2 (regression coefficient 0.20; 95%CI [−0.01 – 0.42]). There was no significant correlation between compression rate and EtCO2 after adjusting for compression depth and cluster, nor between survival and EtCO2 levels.
Conclusion: We found that deeper chest compressions correlated with higher EtCO2 levels. Based on this relationship, changes in EtCO2 during the actual resuscitation event may be reflective of the CPR quality being delivered. This work also suggests the feasibility of continuous monitoring of physiology during CPR to ensure resuscitation quality.