A hospitalized 72-year-old man has not voided since catheter removal 8 hours ago. He had a sigmoid colectomy for recurrent diverticulitis 2 days ago. He is currently receiving 5% dextrose and 0.45% saline. His temperature is 100.8°F. Most likely cause of inability to void?
A) Neurogenic bladder
B) Acute urinary retention
C) Postoperative ileus
D) Dehydration