| 19991-9 | Alveolar-arterial oxygen Partial pressure difference |
| 53809-0 | Oxygen.alveolar - arterial adjusted to patient's actual temperature Respiratory system |
| 60817-4 | Gastric-arterial pCO2 gap |
| 60818-2 | Gastric-end tidal pCO2 gap |
| 96976-6 | Carbon dioxide end tidal baseline - sub-maximal exercise delta |
