Positive airway pressure (PAP) is a mode of respiratory ventilation used primarily in the treatment of sleep apnea.
PAP ventilation is also commonly used for those who are critically ill in hospital with respiratory failure, and in newborn infants (neonates). In these patients, PAP ventilation can prevent the need for tracheal intubation, or allow earlier extubation. Sometimes patients with neuromuscular diseases use this variety of ventilation as well.
CPAP is an acronym for Continuous Positive Airway Pressure.
The main indications for PAP are congestive heart failure and chronic obstructive pulmonary disease; there is some evidence of benefit for those with hypoxia and community acquired pneumonia.
The most common conditions for which PAP ventilation is used in hospital are congestive cardiac failure and acute exacerbation of obstructive airway disease, most notably exacerbations of COPD and asthma.
Usually PAP ventilation will be reserved for the subset of patients for whom oxygen delivered via a face mask is deemed insufficient or deleterious to health (see CO2 retention). It is not used in cases where the airway may be compromised, or consciousness is impaired.