Final answer:
The nurse's first action if an allergic reaction to a blood transfusion occurs is to shut off the infusion to prevent the introduction of more allergens to the patient's system, followed by securing airway and breathing, and then contacting the health care provider for further instructions.
Step-by-step explanation:
An allergic reaction during a blood transfusion is a serious event that can rapidly escalate into life-threatening anaphylaxis. Immediate action is required to prevent further complications. When a patient exhibits signs of an allergic reaction - such as fever, chills, itching, hives, shortness of breath, hemoglobinuria, and hypotension or severe anaphylaxis - the very first step is to stop the blood transfusion immediately. This halts the introduction of additional allergens into the patient's system.
Once the infusion is stopped, the second priority is to ensure the patient's airway is open and that they are breathing adequately. After securing the airway and breathing, the nurse should then call the health care provider (HCP) for further instructions and be prepared to administer emergency medications as prescribed, such as an epinephrine injection to counteract severe allergic reactions. Antihistamines or corticosteroids may also be given, but these follow the emergency intervention and are not the initial steps in treating an acute allergic reaction to a blood transfusion.