A 53-year-old woman with Eisenmenger syndrome related to a ventricular septal defect is evaluated in the emergency department for fever and chills over the past 12 hours. She has dysuria and urinary frequency. Her only outpatient medication is bosentan.
On physical examination, temperature is 38.2 °C (100.8 °F), blood pressure is 110/70 mm Hg, pulse rate is 86/min and regular, and respiration rate is 20/min. Oxygen saturation on ambient air is 85%. BMI is 24. Digital clubbing and cyanosis are evident. The estimated central venous pressure is elevated with a prominent a wave. The apical impulse is normal. A prominent parasternal impulse is present at the left sternal border. The S1 is normal; the S2 is loud. A soft holosystolic murmur is heard at the left lower sternal border. Mild right flank tenderness is noted.
A urinary Gram stain is positive; urine and blood culture results are pending. The hemoglobin level is 18 g/dL (180 g/L), hematocrit is 55%, and the leukocyte count is 20,000/µL (20 × 109/L).
In addition to intravenous antibiotic administration, which of the following is the most appropriate management?