A patient underwent a surgical procedure has a urinary catheter. Eight hours after catheter removal and drinking fluids, the patient has not been able to void. What is the nurse's first action to assess for urinary retention?
a) Measure the patient's bladder volume with ultrasound
b) Encourage the patient to walk around the room
c) Attempt to insert a urinary catheter again
d) Perform a bladder scan to assess for residual urine