Question

During morning rounds, the clinical team reviews the status of a patient who was hospitalized four days ago due to massive ascites and lower extremity edema. The patient has long-standing cirrhosis secondary to chronic hepatitis C virus infection. Despite medication compliance prior to admission, his weight had increased significantly over the preceding month. Current vital signs include a temperature of $36.9^\circ\text{C}$ ($98.4^\circ\text{F}$), blood pressure of $92/56\text{ mmHg}$, and heart rate of $94/\text{min}$. Physical examination reveals a tensely distended abdomen with a positive fluid wave and bilateral pitting edema extending to the thighs. The lungs are clear to auscultation. Recent laboratory values show a serum sodium of $131\text{ mEq/L}$, serum potassium of $4.2\text{ mEq/L}$, serum bicarbonate of $17\text{ mEq/L}$, blood urea nitrogen of $55\text{ mg/dL}$, and serum creatinine of $2.8\text{ mg/dL}$ (baseline was $1.0\text{ mg/dL}$ three weeks prior). A diagnostic paracentesis performed upon admission showed an absolute neutrophil count of $110/\text{mm}^3$. Urinalysis demonstrates no red blood cells, white blood cells, or casts, and the urine sodium concentration is $8\text{ mEq/L}$. Renal ultrasonography reveals normal renal architecture without obstruction. Over the past 48 hours, all diuretic therapy was withheld, and the patient was administered intravenous albumin at $1\text{ g/kg}$ per day. Today, his serum creatinine remains elevated at $2.9\text{ mg/dL}$. Which of the following is the most appropriate next step in management?