Peak vs. plateau airway pressure

Physiology - Respiratory

Static compliance is measured in the absence of gas flow, and is based on plateau pressure:

Cstat = Vt/(Pplat – PEEP)

Dynamic compliance is measure in the presence of gas flow, and is based on peak pressure:

Cdyn = Vt/(Ppeak – PEEP)

Remember these three scenarios to understand how compliance curves will change:

  • Pulmonary emboli do not change resistance or compliance, so both compliance curves are unchanged.
  • Plugging or bronchospasm increases airway resistance (Raw) and peak pressure, so dynamic compliance curve shifts to the right and flattens. Plateau pressure and static compliance are unchanged.
  • Tension pneumothorax, atelectasis, pulmonary edema, pneumonia, bronchial intubation cause reduced lung compliance which increases both peak pressure and plateau pressure, so both static and dynamic compliance fall.


Answered correctly


Year asked