Quantitating urea removal in patients with acute renal failure: lost art or forgotten science?

A 67-year-old woman is admitted to the surgical service with a high fever, a painful and distended abdomen, jaundice, and almost complete anuria. A urinalysis revealed dark red-brown urine notable for albuminuria, erythrocytes, leukocytes, and casts. The patient was treated with antibiotics, but continued to have oligoanuria. On the eighth day of hospitalization, the following laboratory tests were obtained: serum potassium, 13.7 mEq/L; BUN, 396 mg/dl. At this time the patient was noted to be encephalopathic with deteriorating clinical condition. Renal replacement therapy was initiated. The characteristics of the initial dialysis treatment are described in Table 1. After the initial dialysis treatment, the patient went on to become nonoliguric, followed by gradual recovery of urea clearance. She survived her acute illness, left the hospital, and at 7 months posthospitalization was doing quite well.