A 56-year-old male with a 20-year history of recurrent cough and sputum production has experienced progressive dyspnea, oliguria, and lower extremity edema over the past 3 years. Symptoms worsened 1 week ago due to a cold. Examination: alert, marked dyspnea, cyanosis, mild conjunctival congestion/edema, jugular vein distension. Diminished breath sounds with fine rales/crackles at lung bases. Normal cardiac size, heart rate 106 bpm, regular rhythm, accentuated P2, no murmurs. Liver palpable 2.5 cm below costal margin, soft/tender, positive hepatojugular reflux, ++ lower extremity edema. Sputum smear shows polymorphic gram-negative bacilli. ABG (room air): pH 7.30, PaCO2 50 mmHg, PaO2 45 mmHg. What is the FIRST-LINE treatment for right heart failure (HF) in this case?