Driving Pressure
Plateau pressure minus PEEP — the cyclic stress the tidal volume itself imposes on the aerated lung.
Definition
Driving pressure (ΔP) is the difference between plateau pressure and PEEP: ΔP = Pplat − PEEP. Because tidal volume divided by driving pressure equals compliance, driving pressure can also be understood as tidal volume normalized to the amount of lung actually available to receive it.
Mechanism
A fixed tidal volume set to a 'safe' 6 mL/kg predicted body weight can still overstress the lung if the aerated lung volume is small, because that volume is then distributed into a smaller functional space — the same tidal volume produces a larger driving pressure in a stiffer, more diseased lung. Driving pressure captures this in a single number, unlike tidal volume alone, which doesn't account for how much lung is actually available to be inflated.
Visual Physiology — Driving Pressure Mechanics
Airway pressure waveform measuring Driving Pressure (ΔP = Pplat - PEEP) during an end-inspiratory hold to quantify cyclical alveolar stress.
Key Visual Takeaways
- Driving pressure (ΔP = Pplat - PEEP) isolates the cyclical elastic distending pressure delivered to the alveoli.
- Normalizes delivered tidal volume to functional respiratory system compliance (ΔP = VT / Crs).
- ΔP = Pplat - PEEP; in observational studies, lower driving pressure is associated with improved survival in ARDS.
Interactive visual
Driving pressure = Pplat − PEEP = 24 − 10 = 14 cmH2O
Within the ≤ 15 cmH2O range associated with lower mortality in retrospective analyses of ARDSNet trial data.
An educational visualization for exploring the relationship between values, not a patient simulation.
Clinical significance
Retrospective analyses of ARDSNet trial data found driving pressure to be the ventilation variable most strongly associated with mortality in ARDS, more so than tidal volume or PEEP individually, making it a practical bedside target once lung-protective tidal volume is already set.
Common ICU applications
- Recalculated after every PEEP or tidal volume change to confirm the strategy is staying within a favorable range, generally interpreted as ≤ 15 cmH2O.
- A rising driving pressure at a fixed tidal volume signals falling compliance — a cue to reassess for a new complication (pneumothorax, worsening edema) rather than simply pushing forward.
- Used alongside PEEP titration: a PEEP change that increases driving pressure has likely overdistended the lung rather than recruited it.
Related concepts
Related topics