Pulmonary function tests (Spirometry)

        Pulmonary function tests (Spirometry) – Spirometry is a specialised test of lung function. It is essential in the diagnosis and follow-up of respiratory disorders such as asthma, chronic obstructive pulmonary disease, interstitial lung disease, etc. It is also needed before major surgery in patients with respiratory diseases to assess the preoperative fitness for surgery. 

                    

The procedure essentially involves breathing through a mouthpiece into a pipe which is attached to the spirometer.  The volume or flow of air being breathed is then measured and used to derive further values as illustrated in the following graph.