A nurse is monitoring the urinary output of an adult client who had a colon resection. Which of the following 24-hour output totals indicates oliguria?

Choice A reason: A 24-hour urine output of 600 mL is above the threshold for oliguria. While it may be on the lower side of normal, it does not meet the clinical definition of oliguria. Choice B reason: Oliguria is defined as urine output less than 400 mL in 24 hours in adults. A total of 380 mL meets this criterion and may indicate renal hypoperfusion, acute kidney injury, or postoperative complications. Prompt evaluation is warranted. Choice C reason: 550 mL is within the normal range for daily urine output and does not qualify as oliguria. It may reflect reduced intake or mild dehydration but is not pathologic. Choice D reason: 720 mL is well within the normal range for adult urine output and does not suggest oliguria. It indicates adequate renal perfusion and function postoperatively.