The surgeon orders hourly urine output measurement for a patient after abdominal surgery. The ...

The surgeon orders hourly urine output measurement for a patient after abdominal surgery. The patient's urine output has been greater than 60 ml/hour for the past 2 hours. Suddenly the patient's urine output drops to almost nothing. What should the nurse
 
  The surgeon orders hourly urine output measurement for a patient after abdominal surgery. The patient's urine output has been greater than 60 ml/hour for the past 2 hours. Suddenly the patient's urine output drops to almost nothing. What should the nurse do first?
  1) Irrigate the catheter with 30 ml of sterile solution.
  2) Replace the patient's indwelling urinary catheter.
  3) Infuse 500 ml of normal saline solution IV over 1 hour.
  4) Notify the surgeon immediately.