During positive pressure ventilation, the manometer rises progressively to a peak pressure (P Peak ). This is the highest pressure recorded at the end of inspiration. P Peak is also called peak inspiratory pressure (PIP) or peak airway pressure.
The pressures measured during inspiration are the sum of two pressures: the pressure required to force the gas through the resistance of the airways (P TA ) and the pressure of the gas volume as it fills the alveoli. PIP is the sum of P TA and P A at the end of inspiration. (At any point during inspiration, gauge pressure equals P TA + P A ) .