Examination of the function of external respiration

“External respiration” is a general term that describes the process of moving air in the respiratory system, its distribution in the lungs and the delivery of gases from the air to and from the blood.

Pulmonary function (RF) is one of the most important diagnostic methods in pulmonology, which is used in the diagnosis of diseases of the bronchopulmonary system. Other names for this method are spirometry or spirography. Diagnosis consists in determining the functional state of the respiratory tract. The procedure is absolutely painless, takes a little time, so it is used everywhere. FVD can be performed in adults and children. Based on the results of the examination, it is possible to draw a conclusion about which part of the respiratory system is affected, how functional indicators are reduced, and to assess the degree of danger of the pathology.

Why is it necessary to study the function of external respiration

Any deviation in the tissues and organs of the respiratory system provokes a violation of the respiratory process, and any changes in the functions of the bronchi and lungs can be detected on the spirogram. The disease can affect the chest, which works as a kind of pump, the lung tissue, which is responsible for gas exchange and oxygenation of the blood, as well as the respiratory tract, through which air must pass freely.

In case of pathology, the respiratory function will show not only the very fact of a violation of the respiratory function, but will also help the doctor determine which part of the lungs is affected, how quickly the disease progresses, what therapeutic measures are best applied. During the examination, several indicators are measured at once, which depend on gender, age, height, body weight, heredity, the presence of chronic diseases and physical activity. Therefore, the interpretation of the results should be made by a physician familiar with the patient’s medical history. Usually, a pulmonologist, therapist or allergist directs the patient to this study.

Moreover, the results of the study of respiratory function help to determine the source of dyspnea and the extent of respiratory system disorders, select the correct treatment and determine the level of its effectiveness, detect reduced lung ventilation and establish the nature of its severity, calculate the reversibility of disorders when using bronchodilators, and also track the frequency of bronchopulmonary modifications. tree during the course of the disease.

Research types

Spirometry (spirometry) is based on the detection of the functional state of the respiratory system. It helps to make a conclusion about which area is affected, how much the functional indicators have decreased, and to what extent these deviations are dangerous.

Pneumotachometry – measurement of airway patency. It is carried out using a special device that determines the speed of air flow during inhalation and exhalation. It is mainly used to study diseases in a chronic form.

The study of respiratory effort – determines the deviation of the maximum speed of air entering the lungs with increased inhalation and exhalation, thereby helping to assess bronchial patency.

Body plethysmography – studies of respiratory function by comparing the results of spirography and indicators of mechanical variations of the chest during the entire breathing cycle. Allows you to detect the real volume of the lungs, which is not displayed during spirometry.

The study of the diffusion capacity of the lungs – reveals an indicator of the ability of the lungs to transport oxygen into human blood. It is considered a significant diagnostic method, therefore it is included in the list of mandatory respiratory function studies for interstitial and disseminated lung diseases.

Spirometry test with bronchodilators – performed to assess the significance of the obstacle. Helps to differentiate chronic obstructive pulmonary disease (COPD) from asthma and determine the stage of the disease.

Indications and contraindications for the procedure

The study of the function of external respiration has the following indications:

• complaints of changes in breathing, coughing and shortness of breath;
• asthma, COPD;
• suspected lung disease;
• increased carbon dioxide and decreased oxygen in the blood;
• examination of the respiratory system in preparation for surgery or invasive lung examinations;
• screening of smokers, employees of hazardous enterprises and persons who have respiratory allergies.

Like any form of research, FVD also has a number of contraindications, including bleeding in the bronchi of the lungs, aortic aneurysm, tuberculosis, stroke or heart attack, pneumothorax, mental or mental disorders.

The process of studying the function of external respiration

First, the patient is explained the method of research and the rules of conduct during the examination: how to breathe correctly, when to breathe with effort, when to hold your breath, and so on. If necessary, the patient is offered additional diagnostics, which will help establish a more accurate diagnosis.

The study of FVD takes place in a sitting position. The patient closes his nose with a clamp and holds a disposable mouthpiece with his mouth, which is combined with the spirometer tube.

This is necessary so that the respiratory process passes only through the mouth, and the entire air flow is taken into account by the spirometer. After installing all the necessary devices, the diagnostic itself begins. As a rule, testing is carried out several times and the average value is calculated to minimize the error.

The duration of the FVD study is always different, since it depends on the methodology, but on average it takes no more than 30 minutes. When conducting spirometry with bronchodilators, as a rule, spirometry is performed first in the classical version, then with an inhalation test. Therefore, the study takes about twice as long. Preliminary data (without doctor’s comment) will be ready almost immediately.

Preparation for research

Before the study of the respiratory function, special preparation is not required, however, it is still worth excluding any physical and nervous stress, physiotherapy; stop eating 2 hours and smoking 4 hours before the diagnosis; empty the intestines and bladder; refrain from taking bronchodilators (ventolin, berodual, atrovent, etc.) and caffeine-containing drugs (including tea and coffee) 8 hours before the examination; exclude inhalation (except mandatory!); wash off lipstick; loosen the tie, unbutton the collar.

Be sure to take a doctor’s referral for diagnosis with you, and if such an examination has already been carried out before, then the results of the previous study.

The patient must know the exact weight and height. Before starting the procedure, you need to be in a sitting position for 15 minutes, so the patient should arrive a little in advance. You need to wear loose clothing that does not restrict the activity of the chest during increased breathing. It is also strictly forbidden to take aminophylline or other similar drugs during the day before the examination. In general, the study of the function of external respiration does not cause any discomfort. This is a safe and painless study. However, if the procedure is carried out in the presence of hidden contraindications, the examination in extremely rare situations can lead to bronchospasm or an attack of prolonged coughing. In this case, the doctor will immediately provide the necessary assistance.

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