Final answer:
The priority nursing action would be to provide emotional support to the spouse of the critical patient.
Step-by-step explanation:
The priority nursing action in this situation would be to provide emotional support to the spouse of the critical patient. In an emergency room, the well-being and emotional needs of the patient's family and loved ones are also important. By offering emotional support, the nurse can help alleviate distress and anxiety, which may positively impact the spouse's ability to cope with the situation.