Spirometry before and after a bronchodilator

First, you complete forced breathing manoeuvres into a spirometer. The clinician then gives a bronchodilator, usually through an inhaler with a spacer, and waits for the medicine to take effect before repeating the manoeuvres.

The two sets of results show whether airflow changes after the medicine. Improvement can support an airway narrowing pattern, but a limited change does not by itself exclude asthma. Clinicians also consider day-to-day symptoms, examination findings, previous treatment, and the quality of your effort.

Check in advance which inhalers to pause and for how long; do not stop regular treatment without specific instructions. Tell the team about heart problems, pregnancy, medicine reactions, or a recent infection. Avoid a heavy meal and strenuous activity if the clinic advises this.

For each set, sit upright and follow the same technique so the comparison is fair. Breathe in fully, then blow out forcefully and keep exhaling until instructed. A temporary fast heartbeat, tremor, dry mouth, or light-headed feeling can occur; report any troublesome symptom.

Seek emergency help for severe breathlessness, blue or grey lips, fainting, confusion, or strong chest pain. After testing, contact a clinician promptly if wheeze or breathing difficulty is increasing, especially if your reliever is not helping as directed.

Ask which measurements changed, whether the change is clinically meaningful, and how the findings fit your symptoms. Confirm when to restart any paused inhaler, whether another test is needed, and what action plan applies if breathing worsens.