End-Tidal CO2 in Cardiopulmonary Resuscitation

End-tidal CO2 (EtCO2) monitoring is a measure of metabolism, perfusion, and ventilation. In the ED, we typically think of a EtCO2 as a marker of perfusion and ventilation. However, EtCO2 is an extremely powerful surrogate for endotracheal tube (ETT) Position, CPR Quality, Return of spontaneous circulation (ROSC), Strategies for treatment, and Termination (of CPR). Do these letters look familiar? They should! In this post we take a deep dive into each of these potential uses of EtCO2 in the ED. Background The PQRST mnemonic comes from a team in Norway who in 2014 published on how it can help providers optimize all the ways that EtCO2 can help with managing patients.1 As a reminder, EtCO2 represents the amount of carbon dioxide at the end of exhalation. Capnography, however, reflects both a number (EtCO2 in mm Hg) and a waveform. Figure 1 reviews the meaning of each phase of the waveform.2 It’s useful to keep these terms separate in our minds when reviewing the PQRST mnemonic. Position of the ETT (P) ACEP’s policy on verification of ETT placement reminds us that physical examination and fogging in the tube are not reliable to confirm placement. Providers should use EtCO2 detectors (e.g. waveform capnography or colorimetry) to confirm ETT position. Ultrasound in the hands of an experienced provider is also recommended. 3 Waveform EtCO2 (versus colorimetric) can be particularly helpful because you may get color change with the first few breaths of an esophageal intubation. This can be misleading and potentially detrimental to the patient. But the waveform does not lie. 2 Quality of CPR (Q) EtCO2 is essentially to ensuring quality CPR. We typically assess quality of CPR by palpable pulses, but this can be challenging and … Continue reading End-Tidal CO2 in Cardiopulmonary Resuscitation