EpistemisAlveolar-arterial oxygen gradient (A-a)
Helps discern whether the origin of postoperative hypoxemia is intrapulmonary (e.g. atelectasis, pneumonia, PE, shunt) or extrapulmonary (e.g. central hypoventilation due to opioid overdose).
Required inputs
| Variable | Example value |
|---|---|
| Presión de Oxígeno en Aire Inspirado (FiO2, %) | 21 |
| Presión Parcial de CO2 Arterial (PaCO2, mmHg) | 40 |
| Presión Parcial de Oxígeno Arterial (PaO2, mmHg) | 95 |
| Presión Barométrica (Patm, mmHg) | 760 |
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
- Surgery and Trauma
- Area
- Specialties
- Variables
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