Final answer:
In case of a hemolytic reaction due to ABO incompatibility, the nurse must stop the transfusion immediately, follow safety protocols by maintaining the IV line with saline, notify the physician, and monitor the patient closely.
Step-by-step explanation:
If a patient presents with hematuria during a blood transfusion, indicating a possible hemolytic reaction due to ABO incompatibility, the immediate actions a nurse should take are: Stop the transfusion, maintain the intravenous line with saline, notify the physician immediately, return the blood bag and tubing to the blood bank for analysis, collect required blood samples from the patient for testing, monitor the patient's vital signs, and administer supportive care as ordered, which may include oxygen and medications like antihistamines or steroids if necessary. This response is critical to prevent further harm to the patient and manage any adverse reactions.