Plateau Pressure (Pplat)

When a patient is on the ventilator, what is plateau pressure?

Let's first start with what are all the components that contribute to peak inspiratory pressure, PIP, (i.e. the highest pressure the ventilator is measuring when a patient fully inhales):

1. Baseline pressure within the alveoli (i.e. PEEP, peak end expiratory pressure).

2. Compliance of the lung.

3. Resistance of the of all the "tubing": bronchioles, bronchi, trachea, ventilator tubing.

4. Flow of the air generates a pressure as well. 

So when you hold at the end of inspiration to get a plateau pressure (i.e. "plat"), you essentially remove two of the components (resistance of tubing & flow) and the PEEP does not change. Thus, you can think of plat pressure as a proxy for Compliance of the Lung.

How can it help you?

When the PIP is high and you measure a plat that is also high, because it is a proxy for compliance, this can help you narrow your differential and address what is going on in your patient. 

• PIP is high & plat is high = Compliance Problem (see Compliance page for differential!)

• PIP is high & plat is normal = Resistance Problem (see Resistance page for differential!)