How to calculate Airway Resistance ( Raw )

Raw = (PIP – Pplat) / Flow

During volume ventilation this equation will estimate the Airway Resistance (Raw). Larger factors influencing Airway resistance are airway diameter and if the air flow is laminar or turbulent.

  • Raw – Airway resistance in cmH2o/L/sec
  • PIP – Peak Inspiratory Pressure in cmH2O
  • Pplat – Plateau Pressure in cmH2O
  • Flow – Flow rate in L/sec

 

PIP – Peak Inspiratory Pressure in cmH2O
Pplat – Plateau Pressure in cmH2O
Flow – Flow rate in L/sec
Raw – Airway resistance in cmH2O/L/sec

 

Airway Resistance