Long, thin limbs and fingers with pectus excavatum point to Marfan syndrome in the patient. Aortic dissection is the most common cause of death in the patient with Marfan syndrome. Therefore, the nurse most vigilantly assesses for a pulsating abdominal mass, which indicates an abdominal aortic aneurysm, which places the patient at risk for exsanguination through dissection. Spontaneous pneumothorax is associated with Marfan syndrome, but the patient is not exhibiting signs of respiratory distress, so this is unlikely. Pulmonary embolism, as evidenced by frothy, pink-tinged sputum and increased retractions is not associated with Marfan syndrome; the nurse would be no more vigilant for this assessment than a patient without Marfan syndrome. Carotid bruits are not associated with Marfan syndrome.