Mean Airway Pressure (Pₘₐw)
Mean airway pressure, square-wave approximation (Marini 1992): [(PIP·Ti) + (PEEP·Te)] / (Ti + Te) in cmH₂O.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Peak inspiratory pressure
- 30 cmH₂O
- PEEP
- 5 cmH₂O
- Inspiratory time
- 1 s
- Expiratory time
- 2 s
Result: Mean airway pressure 13.3 cmH₂O (PIP 30, PEEP 5).
The tool opens with these values already filled in. Replace them with your own.
What the result means
- Use
- A determinant of mean alveolar pressure and oxygenation; it feeds the oxygenation index.
What you enter
- Peak inspiratory pressure (PIP)
- PEEP
- Inspiratory time (Ti)
- Expiratory time (Te)
How this is calculated
- Formula
- Pₘₐw = [(PIP·Ti) + (PEEP·Te)] / (Ti + Te), the square-wave approximation.
Marini JJ, Ravenscraft SA. Mean airway pressure: physiologic determinants and clinical importance — Part 1: physiologic determinants and measurements. Crit Care Med. 1992;20(11):1604-1616. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.