Noninvasive ventilation

3noWe used bilevel positive airway pressure ventilation (BiPAP; Respironics, Inc.) through a nasal mask to ventilate 57 consecutive, unselected patients with acute respiratory failure who were unresponsive to oxygen and medical therapy alone. We applied noninvasive positive pressure ventilation for almost 22 hours daily, with a median inspiratory positive airway pressure of 15 cm H2O (maximum, 20 cm H2O; minimum, 8 cm H (2O)) and a median expiratory positive airway pressure of 4 cm H2O (range, 8 cm H2O to 3 cm H2O). Seven patients had hypotension (systolic blood pressure