EpistemisAlveolar Gas and Expected PaO₂, Corrected for Age and Altitude
The alveolar gas equation stops working as soon as the patient is not at sea level: in Bogotá or Quito the barometric pressure is around 550 mmHg and a PaO₂ of 65 mmHg is normal, not hypoxemia. This calculator adjusts the expected gradient to age and atmospheric pressure to actual altitude. The pressure is derived from the international standard atmosphere; Local measurements in tropical latitude are usually about 10 mmHg higher.
Required inputs
| Variable | Example value |
|---|---|
| Age (years) | 40 |
| Altitude of the place (meters above sea level) | 2640 |
| FiO₂ (fraction, 0.21 to 1.0) | 0.21 |
| PaCO₂ measurement (mmHg) | 31 |
| PaO₂ measurement (mmHg) | 65 |
Run the calculation in the app
This page explains the score but does not run it. In Epistemis, the calculator validates units, flags values outside physiological ranges, and provides the interpretation that a number alone cannot convey.
Epistemis is educational review material. It is not a medical device, does not diagnose or prescribe treatment, and does not replace formal medical training, current clinical guidelines, or professional clinical judgment.
- Specialty
- Pneumology and Respiratory
- Area
- Internal Medicine
- Variables
- 5