ICCN Articles

Driving Pressure: The Ventilator Number Worth Watching

By Javier Castaneda ·

Among the many numbers on a ventilator, driving pressure has emerged as one of the most useful for protecting injured lungs. It is simple to calculate, closely tied to outcomes, and easy to overlook. This guide explains what driving pressure is, why it matters, and how to lower it.

What Driving Pressure Is

Driving pressure is the difference between the plateau pressure and the PEEP (driving pressure = plateau pressure minus PEEP). Mathematically it equals the tidal volume divided by the compliance of the respiratory system, so it represents how much pressure is needed to deliver each breath into the lung that is actually open and available. In effect, it is the strain placed on the aerated lung with every breath.

Why It Matters

Analyses of ARDS trials have found that driving pressure is strongly associated with mortality, often more tightly than tidal volume or plateau pressure considered alone. The intuition: a fixed tidal volume can be dangerous in a small, stiff lung but tolerable in a larger, more compliant one, and driving pressure captures that relationship in a single number. A commonly cited target is to keep driving pressure under about 15 cm H2O, with lower generally being better.

How to Lower It

  • Reduce the tidal volume toward the lung-protective range so each breath strains the lung less.
  • Optimize PEEP: the right level can recruit collapsed lung, improving compliance and thereby lowering driving pressure, while too much PEEP overdistends and can raise it.
  • Reassess after every change, since driving pressure reflects the balance of both settings against the patient’s lung.

The Bottom Line

Driving pressure (plateau minus PEEP) is a one-number summary of the strain that ventilation places on the lung, and keeping it low is a practical, evidence-linked way to ventilate more gently. Calculate it, watch it, and let it guide tidal volume and PEEP together. For deeper, evidence-based ventilation guidance, explore more from the Interprofessional Critical Care Network.