Deciphering spirometry. What are the normal indicators of

Spirometry is a method of studying breathing, which consists in measuring the capacity of the lungs, as well as the rate of inspiration and expiration.

Spirometry is performed in diseases of the respiratory system, if the patient complains of coughing, sputum discharge, dyspnea.

The study helps to determine the stage of the disease, to reveal the degree of treatment effectiveness.

How and when is spirometry performed?



Spirometry can be given to children older than six years. The procedure is carried out in the morning, after some time after breakfast. Before the procedure, the patient should simply sit for about fifteen minutes. Spirometry is carried out quickly, while it does not cause pain and other unpleasant sensations. The patient's nose is clamped with a special clamp to temporarily exclude nasal breathing. Then follows the connection to the spirograph - a special device for recording changes in air volumes. The patient takes a deep breath, holds his breath and exhales quietly. For five minutes the researcher must breathe calmly, then it is necessary to take a deep exhalation as far as possible, a similar deep breath and repeat a deep exhalation-inhalation. This is one cycle. It is necessary to conduct two more such cycles.

Spirometry parameters



There are many indicators of breathing, but it will be about the most basic. So, the parameters of spirometry:

  • The forced vital capacity of the lungs.

  • Volume of exhalation in the first second.

  • Respiratory volume.

  • The Gensler index.

  • The index is tiff.

  • Capacity of lungs.


  • The indicators of the study directly depend on the patient's health and age. Normal values ​​of the tidal volume can be from 500 to 800 ml, the volume of forced exhalation in the first second is 75%. The index of tiff can be at least 70 percent. Deciphering spirometry involves calculating the remaining indicators using special formulas, so it is difficult to describe the normal parameters.

    Deciphering spirometry helps to identify the type of breathing disorder, which are divided into two types:

  • Obstruction. This type of disturbance of the respiratory system is a violation of patency against the background of edema of the mucous membrane, spasm, the presence of a large volume of sputum in the bronchi. With obstruction, the ratio of forced expiratory volume in the first second to the vital capacity of the lungs is less than 70 percent, and the forced vital capacity of the lungs is more than 80 percent.

  • Decrease in the volume of lung tissue or its extensibility . This type of disturbance of the respiratory system is called restriction. In this violation, the forced vital capacity of the lungs can be less than 80 percent, the ratio of the expiratory volume in the first second to the forced vital capacity of the lungs is more than 70 percent.


  • Spirometry helps assess the state of the respiratory system, identify lung diseases, cardiovascular pathology, and determine their severity and choose the right treatment. Smokers should undergo spirometry every year.