Exhalation spirometer: what to know

A spirometer is connected to a mouthpiece. You usually breathe in fully, seal your lips around the mouthpiece, and breathe out as hard and as long as instructed. The device records airflow and the volume of air exhaled. The pattern can help a clinician assess narrowed airways, monitor a known lung condition, or compare breathing before and after treatment. Results are interpreted alongside symptoms, examination findings, age, height and other personal factors; a single reading does not provide a diagnosis by itself.

Follow the clinic’s instructions about inhalers, meals and activity because some medicines or strenuous exercise can affect the reading. Wear comfortable clothing and tell the tester if coughing, chest pain or dizziness makes the manoeuvre difficult. Several attempts are often needed so the team can check that the effort was consistent. Sit or stand exactly as instructed, keep the mouthpiece sealed, and report discomfort rather than forcing through it.

Contact a clinician promptly for new or worsening breathlessness, blue or grey lips, severe chest tightness, fainting, or trouble speaking in full sentences. If symptoms become severe during testing, stop and tell the tester immediately. Do not use a home reading to delay urgent help. For background on the procedure, see Spirometry; the device itself is described under Spirometer.

Ask what each measurement represents, whether you should pause any inhaler before testing, and how your result compares with your previous readings. Clarify when repeat testing or another breathing assessment is needed.