A 74-year-old man comes to the emergency department for 18 hours of worsening suprapubic discomfort and inability to urinate. He has a history of benign prostatic hyperplasia and stopped taking his tamsulosin 1 week ago. He appears uncomfortable. Vitals are stable. Physical exam shows a distended, tender bladder. A Foley catheter is placed, and 1.2 L of urine is drained. Laboratory studies obtained shortly after catheterization show:

• BUN: 54 mg/dL
• Creatinine: 2.8 mg/dL
• Urine sodium: 12 mEq/L
• Urine creatinine: 120 mg/dL
• Plasma sodium: 140 mEq/L
• Plasma creatinine: 2.8 mg/dL

Urinalysis is otherwise unremarkable. Which of the following best describes the expected change in glomerular filtration rate (GFR) and the most likely fractional excretion of sodium (FENa) in this patient at this stage?

(FENa = [Urine Na × Plasma Cr] / [Plasma Na × Urine Cr] × 100)