What is a spirometry

Spirometry is an extremely simple test which consists of performing some breathing maneuvers by breathing into a mouthpiece connected to an instrument. The instrument is able to measure the passage of air and tell if the spirometry is normal, altered in an obstructive sense, altered in a restrictive sense. In practice, it is necessary to completely fill the lungs with air and then blow the air trapped into the lungs with all possible force. until the end. If the airways (larynx, trachea, bronchi) that carry the air into the lungs are in order, in a second we will be able to let out almost all the trapped air (more than 70%). If, on the other hand, the bronchi are blocked, less air will come out, in particular less than 70%. The less air comes out, the more the bronchi are clogged. At this point we can make the patient breathe a bronchodilator drug (Ventolin spray) and check after a few minutes if the bronchi have opened (reversibility test). The opening of the bronchi, ie reversibility, is characteristic of bronchial asthma. On the other hand, when the bronchi do not open, we are faced with a non-reversible bronchial disease, in particular COPD (chronic obstructive pulmonary disease). Asthma is a chronic inflammatory disease of the bronchi, both allergic and non-allergic in nature. COPD, on the other hand, is the disease of smokers or those who have breathed a lot of dust for professional reasons. We can measure not only how the air comes out, but also how it enters. This is because when the obstruction is in the larynx and in the upper part of the trachea, the air finds it more difficult to enter than to exit. Other diseases instead give a restrictive alteration of spirometry. In practice, it is as if the lung had shrunk, and what we see in spirometry is a reduction in the amount of air, without any alteration in either entering or exiting. We see this type of alteration for example in pulmonary fibrosis, heart failure, pleural effusions, severe changes in the rib cage such as kyphoscoliosis. Spirometry is a test that must be done and evaluated in a clinical setting. It makes no sense to do a spirometry and not link it to a pulmonological evaluation.