The absence of cardiac output and pulmonary blood flow often results in CO2 levels that fall abruptly. Properly administered, capnography can help to identify lower end tidal CO2 (EtCO2) levels so that appropriate changes in CPR such as rate or force of compression can take place.
In the 2010 update of CPR Guidelines, the American Heart Association recommend “the use of quantitative waveform capnography for confirmation and monitoring of endotracheal tube placement.”