Bilevel positive airway pressure (e.g., BiPAP™) delivers two pressure levels according to the respiratory cycle and improves ventilation, oxygenation, and alveolar recruitment. BiPAP provides both an inspiratory positive airway pressure as well as a continuous expiratory positive airway pressure, and the difference between these reflects the tidal volume. NPPV can provide modes nearly identical to standard ICU ventilators, such as pressure, volume, assist control, or even proportional assist ventilation. Patient-ventilator interfaces for NPPV include a face mask, nasal mask or plugs, or a helmet that covers the head. Although the face mask may be less comfortable and more difficult to monitor for aspiration, it provides better physiologic performance (less resistance to airflow and less air leak) when compared to nasal devices.1