|Bhavani Shankar Kodali||Brigham and Women's Hospital, Boston.||Anesthesiology 2013; 118:192–2013|
In an article on this subject, I wrote for Anesthesiology, I used PETCO2. I think this is correct and should be used as standard nomenclature. It reflects what we mean ie partial pressure of end tidal CO2. ETCO2 can used if the measurements are being conveyed as CO2 concentration rather than partial pressure.