Spirometry is designed to assess the condition of a person's lungs. The procedure has a number of clinical purposes, including evaluative, educational, and diagnostic. This study is prescribed to identify lung pathologies of various origins, monitor the patient's condition and evaluate the therapeutic effectiveness of treatment. In addition, spirometry is performed to teach a person the correct breathing technique. The scope of this type of research is quite wide. In this article, we will consider the procedure for spirometry, indications, contraindications and features of its use.
What is the FEV1 norm, we will consider in this article.
Indications
The human respiratory system consists of three main elements:
- Airways that allow air to pass into the lungs.
- Lung tissue that promotes gas exchange.
- Chest, essentially a compressor.
Failure in the work of at least one of these elements depresses the functioning of the lungs. Spirometry allows you to evaluate respiratory parameters, diagnose existing pathologies of the respiratory tract, characterize the severity of the disease and understand whether the prescribed therapy is effective.
The norm of lung volume is of interest to many.
Indications for spirometry are:
- Regular respiratory illnesses.
- Chronic cough, shortness of breath.
- In addition to other airway examinations in the diagnosis of pulmonary pathologies.
- Search for the causes of failure in gas exchange processes in the body.
- Risk assessment of prescribed therapy in the treatment of lungs and bronchi.
- Identification of signs of airway obstruction (in the case of smoking patients) in the absence of severe symptoms of this pathology.
- General characteristics of the physical condition of a person. What is the volume of maximum ventilation of the lungs, consider below.
- In preparation for surgery and lung exams.
- Diagnosis of early stages of chronic obstructive pulmonary disease, monitoring of development and evaluation of further prognosis.
- Determination of the degree of damage to the respiratory function in tuberculosis, bronchial asthma, bronchiectasis, etc.
- Restriction diagnostics.
- Allergic reactions (especially those of an asthmatic nature).
All of the above cases are the reason for the appointment of spirometry. This type of research is not widespread,a lot of people just don't know about it. However, it is very popular in such medical fields as allergology, pulmonology and cardiology. Together with spirometry, the patient can be directed to dynamometry, which determines the strength of the pulmonary muscles. Peak expiratory flow is also detected here.
The main value of spirometry, otherwise called the study of the function of external respiration or respiratory function, plays in the diagnosis of chronic obstructive pulmonary disease and asthma. Experts advise to undergo a lung ventilation test regularly if the patient has one of the aforementioned pathologies. This will help prevent the occurrence of associated complications.
Table of normal spirometry values is shown below.
General information
Research of respiratory function is carried out using a spirometer. This is a special device that is able to read lung parameters during a functional examination. It can also stimulate the respiratory function. This is especially true for patients who have undergone surgery on the lungs and have certain problems with the respiratory system.
Types of spirometry
Spirometers come in many varieties, including:
- Computer. Equipped with ultrasonic sensors. Referred to as the most hygienic spirometer. It has a high accuracy of indicators, as it contains a minimum of internal details.
- Pletysmograph. This is a special chamber where the examined patient is located, and special sensors transmit indicators. This type of spirometerconsidered the most accurate at the moment.
- Water. Does not apply to ultra-precise spirometers, but the measurement range is quite wide.
- Dry mechanical. The device is quite small, while it can read information in any position of the patient. The range is rather short.
- Stimulating or motivating.
The methods of the procedure are also different. Breathing can be examined at rest, or forced expiration is assessed, as well as ventilation of the lungs to the maximum possible. The norm of lung volume is indicated as average. There is also such a thing as dynamic spirometry, which shows the functioning of the lungs at rest and immediately after exercise. Spirometry with a drug reaction test is sometimes used:
- Test with drugs - bronchodilators, such as "Ventolin", "Salbutamol", "Berodual", etc. Such medications have an expanding effect on the bronchi and help to detect spasm in a latent form. Thus, the accuracy of the diagnosis is increased and the effectiveness of the therapy is evaluated. It is important to understand that obstructive pulmonary disease leads to changes in the flow-volume loop.
- Expert provocative test. It is carried out to clarify the diagnosis of asthma. Such a test can reveal hyperreactivity and emerging spasm in the bronchi. The test is performed using methacholine, which is inhaled by the patient during spirometry. In the spirometry table, normal values are indicated veryin detail.
Additional study of diffusion function of the lungs
Modern spirometry devices allow an additional study of the diffusion function of the lungs. This applies to methods of clinical diagnostics. The study involves assessing the qualitative characteristics of oxygen entering the blood and carbon dioxide released during inhalation and exhalation. If diffusion is reduced, this is a sign of serious pathologies in the function of the respiratory organs.
In the field of spirometry, there is another important study called bronchospirometry. This examination is carried out using a bronchoscope and allows you to evaluate the lungs and external respiration separately. For bronchospirometry, anesthesia should be administered. The examination helps to calculate vital capacity, minute volume of the lungs, respiratory rate, etc.
Preparation and implementation
To obtain the most accurate test results, it is important to properly prepare for spirometry, especially when performing the procedure on an outpatient basis. The study of forced expiratory volume is carried out on an empty stomach in the morning, or at another time, but with the condition of skipping meals. If this is not possible, then it is recommended to eat something low-fat in a small amount a few hours before the procedure.
Recommendations
There are other recommendations for preparing for spirometry, namely:
- Stop smoking before your procedure.
- Don't drink tonic drinksthe day before the examination.
- Drinking alcohol before spirometry is also prohibited.
- Sometimes you may need to stop taking certain medications.
- Clothes during the procedure should not hinder movement and interfere with breathing.
- Before the procedure, the doctor must measure the height and weight of the patient, as these indicators are important for evaluating the results of the study.
- Before starting the procedure, you need to be at rest for about 15 minutes, so you should come in advance. Breathing should be calm.
Spirometry is performed on an outpatient basis. Different methods and types of research involve different sequences of actions. The algorithm of steps during the examination may also be influenced by the patient's age and general he alth. If we are talking about conducting spirometry in a child, then the creation of comfortable conditions is considered a prerequisite so that the child does not experience fear and excitement. Otherwise, the readings may be blurred.
Standard Conditions
Standard conditions for spirometry:
If the patient does not have information about his height and weight, the doctor takes the necessary measurements. Before starting the procedure, a special disposable mouthpiece is put on the device.
Enter patient information into the spirometer program.
The doctor explains how to breathe during the study, how to inhale as much as possible. The position of the patient should be with a flat back and a slightly raised head. Sometimesspirometry is carried out in a supine or standing position, which is mandatory recorded in the program. The nose is clamped with a special clothespin. The patient's mouth must fit snugly around the mouthpiece, otherwise readings may be underestimated.
The study begins with a phase of calm and even breathing. At the request of the doctor, a deep breath is taken and exhaled with maximum effort. Next, the air velocity is checked during a calm exhalation. To get the full picture, the breath cycle is repeated several times.
Duration of the procedure no more than 15 minutes.
Indicators and FEV1 norm
Spirometry provides data on many indicators that have certain norms. Interpretation of the results of the study makes it possible to identify pathologies in the respiratory system and prescribe the correct therapy. The main indicators of spirometry include:
- WISHED. This is nothing more than the vital capacity of the lungs, which is calculated by the difference between the volume of inhaled and exhaled air. This is the actual figure. There are other indicators besides FEV1.
- FZhEL. actual lung capacity. It is also determined by the difference between the volume of inhaled and exhaled air, however, exhalation in this case must be forced. The norm is 70-80% WISH.
- ROVD. This is the inspiratory reserve volume. Determines the volume of air that the patient can inhale after a standard breath. Norm 1, 2-1, 5 liters
- ROvyd. Expiratory reserve volume. This is the volume of air inhaled after a standard exhalation. The norm is 1.0-1.5 liters.
- OELor total lung capacity. Normally, this is 5-7 liters.
- FEV norm 1. The volume of exhaled air at maximum forcing in the first second. The norm is more than 70% FVC.
- Tiffno index. Designed to determine the quality of the patency of the respiratory system. Norm 75%.
- PIC. Exhaled air volume. The norm is more than 80% FEV1.
- MOS. Instantaneous volumetric velocity. This is the rate at which air is exhaled. More than 75% is considered normal.
- RR or respiratory rate. The norm is 10-20 breathing maneuvers per minute.
There are certain features of spirometry in children. The first is age, the child should not be younger than five years old. This limitation is explained by the fact that at a younger age, the child is not able to exhale correctly, which will reduce performance. From the age of nine, a child can be examined as an adult. Before this age is reached, it is important to create a comfortable atmosphere for the baby with the use of toys and friendly treatment. For this reason, spirometry in young children should be performed in special centers specialized in pediatrics.
Before the procedure, it is important to explain to the child how to inhale and exhale. Sometimes pictures and photos are used for clarification. The specialist must carefully monitor that the child's lips fit snugly around the mouthpiece.
Deciphering the results obtained
Indicators obtained during spirometry,compared with the norm, taking into account gender, weight and age. The survey conclusion is a graph with the interpretation of indicators. An explanation of the results obtained can be given by the attending physician.
The following data is decrypted:
- The inhaled volume of air in milliliters.
- Expired volume after the deepest breath.
- Expiratory gas volume.
- The difference between inhaled and exhaled volume of air.
- Expiratory and inspiratory speed.
- Forced exhaled air volume.
Features of the procedure
Spirometry in adults can be performed by a number of specialists, including a pulmonologist, a nurse, or a functional diagnostician. In childhood, the procedure is performed by a pediatrician. There are also compact spirometers that allow you to do the simplest test at home. This is true for people with asthma who need to control possible attacks.
Spirometry is a safe procedure and allows you to use it without restrictions. Side effects include slight dizziness during the procedure, but this phenomenon disappears after a couple of minutes.
However, forced inhalation and exhalation can affect intracranial and intra-abdominal pressure, so the procedure is not recommended after abdominal surgery, myocardial infarction, stroke, pulmonary hemorrhage, pneumothorax, hypertension and poor blood clotting. Age over 75years is also a contraindication.
We have considered the FEV1 norm and other indicators.
