A nurse is teaching a client who has acute kidney injury about the oliguric phase. Which of the following information should the nurse include in the teaching?

A. Renal function is reestablished: Renal function is not reestablished during the oliguric phase. This phase is characterized by reduced kidney function, with impaired filtration and accumulation of waste products in the blood. Recovery occurs later in the diuretic and recovery phases. B. The glomerular filtration rate (GFR) recovers: The GFR does not recover in the oliguric phase. Instead, it remains severely reduced, which is the reason urine output declines. Recovery of GFR is expected in the later phases as renal tissue begins to heal. C. Urine output is less than 400 ml per 24 hr: The hallmark feature of the oliguric phase is urine output below 400 mL per day. This occurs due to decreased GFR and impaired tubular function, leading to significant fluid retention, electrolyte imbalance, and accumulation of nitrogenous wastes. D. BUN and creatinine levels decrease: During the oliguric phase, BUN and creatinine levels increase because of reduced clearance of metabolic wastes. The accumulation of these substances contributes to uremia, which often necessitates careful monitoring and sometimes dialysis.