The most appropriate management is noninvasive positive pressure ventilation (NPPV) and supplemental oxygen. This patient has developed respiratory insufficiency due to heart failure with pulmonary edema and pleural effusions. His dyspnea and hypoxia are due to fluid in the alveolar space and interstitium of the lungs, as well as to some degree of pulmonary restriction caused by the effusions. NPPV consists of delivery of positive airway pressure breaths without the use of an endotracheal tube; the interface between the patient and NPPV device is a tight-fitting mask. NPPV settings include an inspiratory positive airway pressure (IPAP) and an end-expiratory positive airway pressure (EPAP). The EPAP component of NPPV helps maintain airway patency and recruits atelectatic or flooded alveoli; it also counters the increased workload imposed by high airway resistance. NPPV decreases the need for mechanical ventilation, improves respiratory parameters, and is associated with improved survival, especially in patients with hypercapnia.

The initial dose of loop diuretic should be at least equivalent to, but preferably greater than, the dose of the patient's chronic outpatient diuretic. If response is not adequate, the diuretic dose should be increased, and an additional synergistic diuretic should be added (usually a thiazide). There is no difference in efficacy or safety of furosemide administration for bolus versus continuous infusion, and there is no indication to change this patient's furosemide dosing.

Intubation and mechanical ventilation could be used to deliver positive pressure support, but this process is invasive, requiring intubation and often sedation, and is associated with an increased risk of hospital-acquired pneumonia. Intubation and mechanical ventilation are options if this patient does not respond to NPPV.

Ultrafiltration is an option for fluid removal and can be performed in the setting of diuretic failure before overt need for kidney replacement therapy. Trials of early ultrafiltration for patients hospitalized with acute decompensated heart failure with volume overload did not demonstrate any definitive effects on mortality. This patient has just received a dose of furosemide, and the diagnosis of diuretic failure has not been established.