End-tidal carbon dioxide concentration during cardiopulmonary resuscitation in patients with pre-hospital cardiac arrest

This study was done to clarify whether end-tidal carbon dioxide (ETCO₂) concentration is an effective monitor as an indicator of survival and prognosis of patients who arrived with cardiac arrest. We measured ETCO₂ concentration in 30 patients with pre-hospital cardiac arrest during cardiopulmonary resuscitation (CPR). Six patients were resuscitated successfully and the others were not. The values of ETCO₂ of the resuscitated patients, at the time of starting advanced life support were varied from 0 to 4.5% (mean 1.4%), which were not different from the values in patients who were not resuscitated (mean 0.87%). In 13 patients who were not resuscitated, the initial values of ETCO₂ during CPR were below 1.0%, whereas the other 11 patients showed high ETCO₂ values (above 2.5%), which were dependent on the degree of chest compression. This suggests that ETCO₂ monitoring during cardiopulmonary resuscitation is a good non-invasive indicator to evaluate the efficacy of chest compression itself, but its initial values during CPR are not correlated with success of resuscitation in patients with pre-hospital cardiac arrest.