Prerenal acute kidney injury Quiz: Ace Your Exams

A 77-year-old woman is brought by ambulance to the emergency department for evaluation of shortness of breath. She has a past medical history of heart failure with reduced ejection fraction (EF 10%), type 2 diabetes mellitus, and hypertension. She has missed multiple days of furosemide. The patient’s daughter found her sitting in her armchair too out of breath to walk to the phone; her daughter called EMS. Temperature is 37°C (98.6°F), blood pressure is 85/50 mmHg, pulse is 115 beats/min, respiratory rate is 28 breaths/min, and oxygen saturation is 88% on room air. Physical examination reveals distended jugular veins. Skin is cool touch in the upper and lower extremities bilaterally. Rales are present at the lung bases bilaterally. There is 4+ pitting edema to the knees bilaterally. Labs reveal a serum creatinine of 4.5 mg/dL (baseline 1.3 mg/dL; reference range: 0.6-1.2 mg/dL), a blood urea nitrogen (BUN) of 60 mg/dL (reference range: 7-18 mg/dL), and a potassium of 6.5 mEq/L (reference range: 3.5-5 mEq/L). Urinalysis is unremarkable, and her urine output is very low. An electrocardiogram shows peaked T waves. Which of the following is the most appropriate next step in the management?