Bilevel noninvasive ventilation provides: 1) IPAP - inspiratory positive airway pressure and 2) EPAP - expiratory PAP at two different levels. This is typically delivered with a tight fitting nasal or face mask which allows for the development of positive airway pressure. The noninvasive therapy should be initiated as early as possible in case of respiratory failure and is best used for short term. "Delta PAP" is the difference between IPAP and EPAP. It directly correlates with the tidal volume delivered. If the "delta PAP" is larger then the tidal volume will be larger and hence it will provide a better alveolar ventilation. INITIAL SETTINGS It is quite safe to start the following initial settings: 1) EPAP 3 to 5 cm H2O (2 - 4 mm Hg) – It can be increased to around 10 cm H2O if ever the oxygenation remains inadequate tidal volume. 2) IPAP 8 to 12 cm H2O (6 - 9 mm Hg) – This can be increased in increments of 2 cm H2O as tolerated by the patient, to a maxim