The prognostic value of end tidal carbon dioxide during cardiac arrest: a systematic review

Introduction: Cardiac arrest is a common presentation to the emergency care system. The decision to terminate CPR is often challenging to heath care providers. An accurate, early predictor of the outcome of resuscitation is needed. The purpose of this systematic review is to evaluate the prognostic value of ETCO2 during cardiac arrest and to explore whether ETCO2 values could be utilised as a tool to predict the outcome of resuscitation.

Method: Literature search was performed using Medline and EMBASE databases to identify studies that evaluated the relationship between ETCO2 during cardiac arrest and outcome. Studies were thoroughly evaluated and appraised. Summary of evidence and conclusions were drawn from this systematic literature review.

Results: 23 observational studies were included. The majority of studies showed that ETCO2 values during CPR were significantly higher in patients who later developed ROSC compared to patients who did not. Several studies suggested that initial ETCO2 value of more than 1.33 kPa is 100% sensitive for predicting survival making ETCO2 value below 1.33 kPa a strong predictor of mortality. These studies however had several limitations and the 100% sensitivity for predicting survival was not consistent among all studies.

Conclusion: ETCO2 values during CPR do correlate with the likelihood of ROSC and survival and therefore have prognostic value. Although certain ETCO2 cut-off values appears to be a strong predictor of mortality, the utility of ETCO2 cut-off values during CPR to accurately predict the outcome of resuscitation is not fully established. Therefore, ETCO2 values cannot be used as a mortality predictor in isolation.