A patient is experiencing oliguria. Which action should the nurse perform first?

A) Assess for bladder distention.
B) Request an order for diuretics.
C) Increase the patient's intravenous fluid rate.
D) Encourage the patient to drink caffeinated beverages.

Oliguria is diminished urinary output in relation to fluid intake. The nurse first should gather all assessment data to determine the potential cause of oliguria. It could be that the patient does not have adequate intake, or it could be that the bladder sphincter is not functioning and the patient is retaining water. Increasing fluids is effective if the patient does not have adequate intake or if dehydration occurs. Caffeine can work as a diuretic but is not helpful if an underlying pathology is present. An order for diuretics can be obtained if the patient was retaining water, but this should not be the first action.