Don’t treat the numbers!
ETCO2 is mainly determined by the:
1) Amount of perfusion to the lungs
2) CO2 concentration in the blood
Poor perfusion to the lungs (deadspace) will cause a disparity between the numerical ETCO2, and what the actual arterial CO2 concentration is.
So, ETCO2 MUST be interpreted in light of the patients pathophysiological state.
Papers mentioned in the podcast:
The Effectiveness of Oxygen Delivery and Reliability of Carbon Dioxide Waveforms: A Crossover Comparison of 4 Nasal Cannulae
Most accurate method of measuring ETCO2 during non-invasive ventilation
PHEMCAST episode on ETCO2
ACC/AHA recommendation on using ETCO2 as a marker of evaluating systemic perfusion in patients with assist devices
Now for the podcast!