A client who has benign prostatic hyperplasia (BPH) with urinary retention is admitted to the hospital with elevated blood urea nitrogen (BUN) and creatinine levels. Which prescribed therapy should the nurse implement first?

A. Insert a foley catheter.: Urinary retention from benign prostatic hyperplasia can cause obstructive uropathy, leading to increased back pressure on the kidneys and subsequent elevation of BUN and creatinine (post-renal acute kidney injury). Immediate bladder decompression with a Foley catheter relieves obstruction, restores urine flow, and prevents further renal damage, making this the priority intervention. B. Infuse normal saline at 50 ml/hr.: While maintaining hydration is important, fluid administration does not address the underlying cause of the renal impairment, which is urinary obstruction. In fact, giving fluids without relieving the obstruction may worsen bladder distention and increase pressure on the urinary tract. C. Schedule a pelvic magnetic resonance imaging test.: Imaging studies can help evaluate structural causes of obstruction, but they are not urgent compared to relieving acute urinary retention. Delaying decompression while awaiting imaging could lead to worsening renal function and complications such as hydronephrosis. D. Draw blood for a complete blood count.: Laboratory evaluation can provide additional information about infection or anemia, but it does not treat the immediate problem. The priority is to relieve the obstruction causing the elevated BUN and creatinine before proceeding with further diagnostic workup.