17th February 2025

A 33-year-old lady is referred for a respiratory appointment after presenting with progressively worsening shortness of breath.

A 33-year-old lady is referred for a respiratory appointment after presenting with progressively worsening shortness of breath. She has noticed a reduced exercise tolerance and cough over the last 4-6 months. She smokes 2-3 cigarettes a day.

On examination she has a quiet bilateral wheeze. Routine blood tests show no obvious abnormality. Chest X-ray shows hyperinflated lungs with a flattened diaphragm.

What investigation is most likely to be diagnostic in this case?

Select the SINGLE most appropriate option from the list below. Select ONE option only.