What should you know about mechanical spirometer?

During spirometry, you breathe through a mouthpiece while sitting upright, with a clip often used to keep air from escaping through your nose. You take a full breath and blow out as hard and as long as instructed. The device displays measurements of airflow and exhaled volume. A clinician may repeat the manoeuvre because effort, technique, coughing or a poor seal can affect the result. The result is interpreted alongside symptoms, examination findings and medical history.

Wear comfortable clothing and follow the clinic's instructions about meals, smoking and inhalers. Bring a list of medicines and mention recent chest infection, surgery, chest pain or breathlessness. Sit upright, seal your lips around the mouthpiece and follow each prompt closely. Temporary coughing, tiredness or light-headedness can occur; tell the tester immediately rather than forcing another breath.

Contact a clinician if breathlessness, wheezing or cough is persistent, worsening or limiting ordinary activity. Seek urgent help for severe breathlessness at rest, blue or grey lips, chest pain, confusion, fainting or inability to speak in full sentences. A mechanical spirometer is a test device and does not treat an acute breathing emergency.

Ask what each measurement means, whether you need to pause any inhaler, and whether repeat testing or a different assessment is appropriate. Ask how symptoms, smoking history and previous lung conditions affect interpretation.