Use End-Tidal Capnography for Placing Orogastric, Nasogastric Tubes, and CPR

End-Tidal to Guide Your Next CPR

A cardiopulmonary resuscitation (CPR) is inherently a scene of chaos with many unknowns, but arguably one of most informative pieces of information, aside from presence of a pulse, is the end-tidal capnogram. End-tidal capnometry made its debut in the advanced cardiovascular life support (ACLS) guidelines in 2010, but its use in cardiac arrest can be found as far back as the 1970s.^7,8 It can be used for prognostication, quality of chest compressions, correct placement of the endotracheal tube, and perhaps even the cause of the arrest.

Figure 3. Using EtCO2 During CPR

When people go into cardiac arrest, they quickly become acidemic and accumulate CO2 in the blood. As CPR and ventilation begin, the CO2 is offloaded in the alveoli, expired, and subsequently sensed by the end-tidal capnometer. End-tidal CO2 has been shown to correlate with cardiac output even in low-flow states such as CPR, making it an indicator of CPR quality.⁹ With every increase of 10 mm in the depth of chest compressions, there is a 1.4 mmHg increase in the end-tidal value, allowing you to monitor whether the compressor is becoming fatigued and in need of relief.¹⁰ That being said, ongoing CPR should produce at least a minimal end-tidal capnogram waveform; if you see a flat capnogram, check your advanced airway for correct positioning.