Airway resistance (peak minus plateau)
Computes inspiratory airway resistance on a ventilated patient: peak inspiratory pressure minus plateau pressure, divided by the inspiratory flow in liters per second.
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
- 38 cmH2O
- Plateau pressure, from an end-inspiratory hold
- 22 cmH2O
- Set inspiratory flow
- 60 L/min
Result: a raised resistance from a wide gap between peak and plateau
The tool opens with these values already filled in. Replace them with your own.
What the result means
- The formula
- Peak inspiratory pressure minus plateau pressure, divided by the inspiratory flow in liters per second.
- Usual range
- Up to about 10 cmH2O per liter per second on a passive adult through an endotracheal tube. Above that is raised.
- Peak up, plateau flat
- A resistance problem: secretions, a kinked or bitten tube, bronchospasm.
- Plateau up
- A compliance problem: edema, consolidation, pneumothorax, abdominal pressure, chest wall. The peak alone cannot tell these apart.
- It needs
- A real end-inspiratory hold, constant square-wave flow in volume control, and a passive patient.
- The tube counts
- A smaller endotracheal tube raises the number with no airway disease, so the trend in one patient says more than the absolute.
What you enter
- Peak inspiratory pressure
- Plateau pressure, from an end-inspiratory hold
- Set inspiratory flow
How this is calculated
Tobin MJ, ed. Principles and Practice of Mechanical Ventilation. 3rd ed. New York: McGraw-Hill; 2013. Hess DR. Respiratory mechanics in mechanically ventilated patients. Respir Care. 2014;59(11):1773-1794. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.