The ventilator has 2 main roles:
- To drive gas into the patient to create inspiration and facilitate oxygenation
- To allow the passive outflow of gas during expiration and facilitate carbon dioxyde elimination
The lung-ventilator unit can be represented by a tube and balloon
Tube = ventilator tubing + ETT + major airways
Balloon = lung alveoli
PAW = Airway pressure (what the ventilator can measure)
PALV = Alveolar pressure (what the alveoli really feel)