What to expect from spirometry for chronic cough

For chronic cough, expect spirometry to measure how quickly and how much air you can exhale through a mouthpiece. You will sit upright while a technician explains the manoeuvre and may use a nose clip. After breathing normally, you take a deep breath and blow out with a fast, sustained effort. The test is repeated to check that the results are dependable; coughing between attempts is common and should be mentioned.

A persistent cough can occur with several conditions, including asthma and other problems affecting airflow. Spirometry can reveal whether air is leaving the lungs more slowly than expected and may be repeated after a reliever medicine. A normal tracing does not explain every cough: reflux, nasal drainage, medicines, infection and other causes may need separate consideration. Your clinician interprets the result with your history and examination.

Check whether the clinic wants you to alter inhalers or other medicines, and follow that advice rather than making changes alone. Avoid restrictive clothing and tell the team about recent illness, chest pain, fainting or surgery. Bring a list of medicines and note when your cough is worse, what brings up sputum, and whether wheeze or breathlessness accompanies it. Rest briefly if the effort makes you light-headed.

Seek urgent care for severe breathing difficulty, blue or grey lips, confusion, chest pain, or coughing up more than a small streak of blood. Prompt assessment is also appropriate for a cough with high fever, rapidly worsening breathlessness, or marked weakness. A chronic cough still needs review when it persists, changes character, disturbs sleep or limits normal activity, even if spirometry is normal.

Ask what the readings show, whether a reliever response or another breathing test is useful, and which non-lung causes of cough should be considered. Ask what symptoms should prompt a sooner appointment and when you will receive the full interpretation.