A 20-year-old man comes to the office due to worsening dyspnea.  The patient reports almost daily episodes of shortness of breath, chest tightness, and cough.  His symptoms started after he moved across the country to attend college 1 year ago.  Medical history includes childhood milk protein allergy and migraine headache.  The patient’s migraines are slightly more intense this year, which he attributes to his busy class schedule, but they remain well controlled with naproxen as needed.  He spends an hour several times a week soaking in a hot tub to relax.  Vital signs are within normal limits.  On physical examination, scattered wheezes and normal heart sounds are noted.  Ocular, nasal, and oropharyngeal mucous membranes are normal.  Spirometry results are shown below.

In addition to appropriate pharmacotherapy, which of the following would be most helpful in relieving the patient’s respiratory symptoms?

A 19-year-old woman is brought to the emergency department after a motor vehicle collision.  The patient’s medical history includes celiac disease and 3 episodes of pneumonia.  Her blood pressure is 80/45 mm Hg and pulse is 130/min.  Physical examination reveals pallor, and ultrasound shows a splenic laceration.  She receives a blood transfusion with O-negative packed red blood cells.  During transfusion, the patient develops facial swelling, generalized hives, and shortness of breath.  Which of the following is the most likely diagnosis in this patient?