(SaO2 15 minutes) while receiving supplemental
oxygen, respiratory acidosis (arterial pH 45 mm Hg), and respiratory rate greater than
25/min for 1 hour. The mode of ventilation was biphasic
positive airway pressure. When such support was
inadequate (hypoxemia, hypercapnea, or respiratory distress),
the patient was reintubated and mechanical ventilation
was resumed