OAD
obstructive airways disease

OI
oxygen index

PaCO₂
carbon dioxide partial pressure

PaO₂
partial pressure of oxygen

PAP
peak airway pressure

Paw
airway pressure

PCIRV
pressure-controlled inverse ratio ventilation

PEEP
positive end-expiratory pressure

PIP
peak inspiratory pressure

Pmus
pressure generated by muscle contraction

Ppl
pleural pressure

PPV
positive pressure ventilation

PS
pressure support

PSV
pressure support ventilation

PT
physical therapy or pulmonary therapy (see article on Pulmonary Rehad in Learn About ARDS section 1)

PTSD
post traumatic stress disorder

P-V
pressure-volume