The use of end-tidal carbon dioxide (ETCO2) measurement to guide management of cardiac arrest: A systematic review.

AIMS: To identify whether any level of end-tidal carbon dioxide (ETCO2) measured during cardiopulmonary resuscitation (CPR) correlates with return of spontaneous circulation (ROSC) or survival in adults experiencing cardiac arrest in any setting. METHODS: Systematic review. We included randomized controlled trials, cohort studies, and case-control studies of adult cardiac arrest in any setting that reported specific (rather than pooled) ETCO2 values and attempted to correlate those values with prognosis. Full-text articles were searched on EmBASE, MEDLINE, and Cochrane Database. The Grades of Recommendation, Assessment, Development and Evaluation (GRADE) guidelines were followed, assigning levels of quality to all evidence used in the meta-analysis. RESULTS: Seventeen observational studies, describing a total of 6198 patients, were included in the qualitative synthesis, and five studies were included in the meta-analysis. The available studies provided consistent but low-quality evidence that ETCO2 measurements ≥10mmHg, obtained at various time points during CPR, are substantially related to ROSC. Additional cut-off values were also found. Initial ETCO2 or 20-min ETCO2>20mmHg appears to be a better predictor of ROSC than the 10mmHg cut off value. A ETCO2<10mmHg after 20min of CPR is associated with a 0.5% likelihood of ROSC. CONCLUSIONS: Based upon existing evidence, ETCO2 levels do seem to provide limited prognostic information for patients who have experienced cardiac arrest. Given the many potential confounders that can influence initial ETCO2 levels, extreme or trending values may be more useful than static mid-range levels. Additional well-designed studies are needed to define optimal timing for the measurement of ETCO2 for prognostic purposes.