| ETCO2 | end-tidal carbon dioxide [concentration] |
|---|---|
| ETPCO2 | end-tidal partial carbon dioxide [concentration] |
| FECO2 | fractional concentration of carbon dioxide in expired gas |
| FiCO2, | FICO2 fractional concentration of carbon dioxide in inspired gas |
| PACO2 | partial pressure of carbon dioxide in alveolar gas |