Driving Pressure

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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.

Abbreviations: respiratory system static compliance (Crs), respiratory system static elastance (Ers), driving pressure (Pdriving), peak pressure (Ppeak), plateau pressure (Pplat), positive end-expiratory pressure (PEEP)

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!

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2 responses to “Driving Pressure”

  1. JT Zavoli Avatar
    JT Zavoli

    Thank you for the information. I have a question about the application of these concepts. Specifically, I am attempting to optimize ventilation for patients with rather high BMI’s in laparoscopic cases where they are in Trendelenburg (more or less standing on their heads). I generally start with a PEEP that is roughly 1/4 their BMI and a VT of 6-8 ml/kg IBW. Do you have a suggested approach to helping to reduce the driving pressure for these patients, which generally does not fall to the 15 cmH2O suggested by literature. I have come across titrating both PEEP and VT, but have not achieved desired results. Is there a specific approach you’d recommend in titrating these parameters? Thank you in advance!

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    1. Rishi Avatar
      Rishi

      Optimizing driving pressures in this specific patient population (obese + abdominal insufflation + steep Trendelenburg) is incredibly challenging, and the short answer is that these patients often have elevated peak/plateau pressures despite tweaking vent parameters, paralysis, etc. “Best PEEP” trials are often difficult to perform in the OR since there’s variables minute-to-minute, but I’ll sometimes do them in the ICU when I can’t use other techniques (e.g., esophageal manometry) to help me find the optimum PEEP.

      Typically I start at a PEEP of 8 cm H2O, increase by 2-3 cm H2O every 5-10 minutes (stopping at a PEEP of 20-25 cm H2O), allow a few minutes for the mechanics to stabilize, and then measure compliance and a plateau pressure (which is also not practical on many OR vents). While doing this trial, I want to ensure the hemodynamics and gas exchange aren’t jeopardized. Eventually I’ve gathered enough data to figure out where the driving pressure is optimized.

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