Final answer:
The priority action by the nurse is to stop the irrigation and remove the tube.
Step-by-step explanation:
The priority action by the nurse is to stop the irrigation and remove the tube. The patient is experiencing severe cramping, which may indicate a complication or intolerance to the irrigation. Continuing with the procedure or replacing the fluid with cooler water will not address the patient's discomfort and may worsen the situation. Stopping the irrigation and removing the tube will provide the patient with relief and allow the nurse to assess the situation further.