The application of mechanical ventilatory support through a mask in place of endotracheal intubation is becoming increasingly accepted and used in the emergency department. Considering this modality for patients with mild-to-moderate respiratory failure is appropriate. The patient must be mentally alert enough to follow commands. Clinical situations in which it has proven useful include acute exacerbation of chronic obstructive pulmonary disease (COPD) or asthma, decompensated congestive heart failure (CHF) with mild-to-moderate pulmonary edema, and pulmonary edema from hypervolemia. It is most commonly applied as continuous positive airway pressure (CPAP) and biphasic positive airway pressure (BiPAP). BiPAP is commonly misunderstood to be a form of pressure support ventilation triggered by patient breaths; in actuality, BiPAP is a form of CPAP that alternates between high and low positive airway pressures, permitting inspiration (and expiration) throughout.

 

Reviews of the literature have shown noninvasive positive-pressure ventilation (NPPV) to be beneficial for COPD, reducing the rate of tracheal intubations and the length of stay.  Recently developed clinical guidelines recommend that NPPV be considered as an adjunct to standard medical therapy in patients with severe COPD exacerbations (pH < 7.35 and relative hypercarbia), as well as in patients with cardiogenic pulmonary edema and respiratory failure without shock or acute coronary syndrome requiring urgent percutaneous coronary intervention.