One hour after arriving on the postoperative unit, a woman who received spinal anesthesia 5 hours ago is complaining of severe abdominal incisional pain. Her vital signs include oral temperature 99.0°F (37.2°C), heart rate 110 beats/minute, respiratory rate 30 breaths/minute, and blood pressure 160/90 mm Hg. The client's skin is pale, and the surgical dressing is dry and intact. Which intervention is most important for the nurse to implement?