Positive airway pressure (PAP) is a mode of respiratory ventilation used primarily in the treatment of sleep apnea, for which it was first developed. PAP ventilation is also commonly used for those who are critically ill in hospital with respiratory failure, and in newborn infants. 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.