title: The prognostic value of end tidal carbon dioxide during cardiac arrest: a systematic review.
abstract: BACKGROUND
  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.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Intensive Care Department, Broomfield Hospital, Chelmsford, United Kingdom. Electronic address: toumao@doctors.org.uk.
authors.forename: Omar
authors.initials: O
authors.lastname: Touma
authors.forename: Mark
authors.initials: M
authors.lastname: Davies
mesh_terms: D002245:Carbon Dioxide / Q000032:analysis*; D016887:Cardiopulmonary Resuscitation; D004638:Emergency Treatment; D006323:Heart Arrest / Q000378:metabolism / Q000503:physiopathology* / Q000628:therapy; D006801:Humans; D011237:Predictive Value of Tests; D011379:Prognosis; D016019:Survival Analysis; D013990:Tidal Volume / Q000502:physiology*
chemical_list: D002245:Carbon Dioxide
keywords: BP; CI; CPR; Cardiac arrest; ED; EMS; ETCO(2); End tidal carbon dioxide; IQR; MAP; NPV; OR; PEA; PPV; Prognosis; RCT; ROSC; SD; VF; VT; blood pressure; cardiopulmonary resuscitation; confidence interval; emergency department; emergency medical services; end tidal carbon dioxide; interquartile range; kPa; kiloPascal; mean arterial pressure; negative predictive value; odds ratio; positive predictive value; pulseless electrical activity; randomised controlled trial; return of spontaneous circulation; standard deviation; ventricular fibrillation; ventricular tachycardia