Driving pressure (Pdriving) is related to tidal volume (VT) and the respiratory system’s static compliance (Crs). At the bedside, Pdriving = plateau pressure (Pplat, determined by an inspiratory hold maneuver) minus PEEP. Based on the boxed equation in the diagram and assuming all other variables remain constant, increasing VT or Pplat and decreasing Crs or PEEP can ultimately increase Pdriving.
A 2015 retrospective analysis by Amato et al. (yes, lots of critiques/limitations) showed driving pressure was an independent predictor of mortality (lower Pdriving = lower mortality) in passively ventilated patients with ARDS suggesting that solely decreasing VT was inadequate in preventing lung injury and enhancing outcomes.
I think about Pdriving as the distending pressure of the lung. The goal is to maintain alveolar recruitment at end-expiration but limit alveolar overdistention during inspiration which could lead to ventilator-induced lung injury. With ARDS in particular, I’ll tweak VT, PEEP, and patient positioning to reduce the Pdriving.
More research is needed to establish the precise function of “driving-pressure-based” mechanical ventilation methods in the ICU and OR. Perhaps one day, setting VT based on Pdriving will replace 6 mL/kg of IBW as the default?
Drop me a comment with your thoughts!