Plateau Pressure
The pressure needed to hold the lung and chest wall at end-inspiratory volume, once flow has stopped.
Definition
Plateau pressure (Pplat) is the airway pressure measured during a brief end-inspiratory pause, once flow has ceased. Because there's no flow, it reflects only the elastic recoil of the lung and chest wall — not airway resistance — making it a proxy for the stress the lung is under at peak inflation.
Mechanism
During active inspiratory flow, airway pressure includes both the resistive pressure needed to drive gas through the airways and the elastic pressure needed to inflate the lung. Pausing flow removes the resistive component, leaving only elastic recoil — Pplat. A gap between peak pressure and Pplat therefore reflects resistance, while Pplat itself reflects compliance and how much lung is available to be inflated at the set tidal volume.
Visual Physiology — Plateau Pressure Mechanics
Plateau pressure is measured during a zero-flow inspiratory hold and reflects respiratory-system static pressure (lung + chest wall), interpreted with driving pressure and PEEP.
Key Visual Takeaways
- An end-inspiratory pause creates zero airflow, removing the resistive pressure drop across the airways.
- Plateau pressure reflects respiratory-system static pressure; it is not a pure direct measure of alveolar stress in every patient.
- A common lung-protective goal is Pplat about <= 30 cmH2O, interpreted with chest-wall mechanics and the broader clinical context.
Interactive visual
Driving pressure = Pplat − PEEP = 28 − 8 = 20 cmH2O
Above the 15 cmH2O range associated with higher mortality — consider reassessing tidal volume, PEEP, and sedation depth.
An educational visualization for exploring the relationship between values, not a patient simulation.
Clinical significance
Keeping plateau pressure ≤ 30 cmH2O is one of the two central targets (alongside low tidal volume) of lung-protective ventilation, because pressures above this threshold are associated with a substantially higher risk of ventilator-induced lung injury.
Common ICU applications
- Checked after every tidal volume or PEEP change in ARDS to confirm the strategy stays within the lung-protective target.
- A Pplat that rises unexpectedly at a fixed tidal volume points to falling compliance and prompts a search for a new problem (worsening edema, abdominal distension, pneumothorax).
- Used together with PEEP to calculate driving pressure, which many clinicians now treat as the more informative single number.
Related concepts