Multiple studies support the use of noninvasive positive pressure ventilation (NPPV) in acute exacerbations of COPD, acute cardiogenic pulmonary edema, and immunocompromised patients (organ transplant) with hypoxic respiratory failure.
The timing of NPPV initiation is important. NPPV should be started as soon as possible, as delays increase the likelihood of intubation
The best predictor of success is a favorable response to NPPV within the first 1 to 2 hours
reduction in respiratory rate
improvement in pH
reduction in PaCO2
Also crucial to NPPV success is a well fitting interface (mask)
Although patients report greater comfort with nasal masks, they also permit more air leakage through the mouth and have been associated with a higher rate of initial intolerance in the acute setting.
For acute applications of NPPV in the ED, a full face mask is preferred
Garpestad E, Brennan J, Hill NS. Noninvasive ventilation for critical care. Chest 2007;132:711-20.