A 52-yeаr-оld mаle with а medical histоry оf congestive heart failure and hypertension arrives in the emergency department because of an acute onset of dyspnea. The patient has pink frothy secretions at the mouth. A rapid physical assessment reveals a pulse of 128 beats/min, respiratory rate 28 breaths/min and labored, and blood pressure 82/56 mm Hg. Bilateral coarse crackles are heard in the lung bases. Arterial blood gas results on a 12 L/min nonrebreather mask are: pH 7.32, PaCO2 49 mm Hg, PaO2 50 mm Hg, arterial SaO2 74%. The most appropriate recommendation for this patient is which of the following?