Evaluating the functional state of pulmonary clinicians recently received much attention. Lung function (LF) are important for the diagnosis and determine the severity of the disease, and for the selection of treatment programs. Dynamic monitoring of patients with repeated studies FVD can make changes in treatment, to predict the course and even the outcome of respiratory diseases in children.
The main objective of the study ERF in most patients is to establish violations of pulmonary ventilation capacity, dominated obstructive, that is caused by changes in air flow to the tracheobronchial tree. Rarely diagnosed restrictive or restrictive disorders that occur due to changes in elasticity of lung tissue. Unlike adult children continued growth and development of bronchopulmonary structures. This explains the fact that even in the presence of chronic respiratory diseases due to high compensatory capacity in lung function are often missing. Children with asthma often have normal functional characteristics, not only in remission, but even in the acute stage of the disease.
The most complete characterization of pulmonary ventilation capacity is possible when studying the structure of total lung capacity. Method bodipletizmografii simultaneously with the study of total lung capacity to evaluate bronchial resistance, which is enough to diagnose the nature and extent of violations. The most popular and affordable method for studying the ERF is to record the flow-volume curve of forced expiratory vital capacity (FVC). The brevity of the study, visual inspection of the forced expiratory maneuver, the computer processing of results, including comparative analysis of different time of the study parameters make this method is indispensable in carrying out functional tests with bronchodilators, bronhokonstriktorami and physical activity.
Evaluation of the indicators is the deviation from the brand name viagra proper value, that is theoretically the most probable value of the indicator set in healthy children, which is calculated by regression equation. To estimate the boundaries of normal values used persentilnoe distribution, as in groups of healthy children is usually different from the normal distribution [1].
Analysis of indicators of flow-volume curve (PAC) expiratory forced vital capacity allows you to identify violations of bronchial conductance, the severity of these disorders, as well as the level of damage: impaired patency of small (or peripheral), the bronchi, large (or central), bronchial disorders or generalized. The initial part of flow-volume curve characterizes the permeability of the central airways. The decline in FEV1 (forced expiratory volume in 1 s), PEF (peak expiratory flow rate) and MOS25 (maximum volume flow rate at exhalation 25% FVC), with good reproducibility of the curve indicates a violation patency large bronchi. Decrease in flow at 50 and 75% of exhaled lung volume (MOS50 and MOS75) and velocity parameters (average speed in the area of 25-50% and 75-85% of FVC: SOS25-50% and SOS75-85%) typical for impaired patency of peripheral respiratory tract. Generalized obstruction characterized by a decrease of all indicators, a decrease in area under the curve, increasing exhalation time, and in pronounced cases - and a decrease in the FVC.
Conducting tests with inhaled bronchodilators solves the problem of reversibility of airway obstruction is detected. These tests are widely used in children with bronchial asthma and chronic nonspecific lung pathology. According to our records, more than half of children with chronic pneumonia and the clinical syndrome of bronchial obstruction give reliable increase in the value of FEV1 bronchodilator inhalation. For proper implementation and evaluation of the test must cancel prior to the study conducted therapy: ?2-agonists, short duration - 6 hours, ?2-agonists, long-lasting - up to 12 hours, prolonged theophylline - 24 hours. When the original study of lung function in children is important to pay attention to the reproducibility of performance: the difference between the maximum and minimum parameters FEV1 and FVC should not exceed 5%. In the case of poor reproducibility of flow-volume curve further evaluation of growth performance is difficult and biased. Re-running the forced expiratory volume makes it possible to identify bronchial obstruction caused by spirometry, ie deterioration of bronchial obstruction in the performance of repeated forced expiratory maneuvers. The existence of this phenomenon is a contraindication for bronhoprovokatsionnyh tests and tests with physical exercise.
Existing methods of assessing pharmacological tests with bronchodilators: the increase in FEV1, expressed as a percentage of the initial value [^ FEV1 ref.]%, The ratio expressed as a percentage of the absolute gain to proper value of [^ FEV1 should.%] - Are unsuitable for pediatric practices because of their significant variability. In pediatric practice, the proposed increase in FEV1 of 12% or more compared with the baseline values assessed as a positive response to inhaled bronchodilator. However, children gain in 12% and can equal 120, and 250, and 360 ml. Therefore, we propose to assess the response to inhaled bronchodilator in the absolute increase in FEV1 values. Commonly used 95-percent confidence interval (1.96 sigma repeatability) was, according to our findings in children and adolescents 190 ml. Therefore, the growth rate in FEV1 of 190 ml or more [^ FEV1] can be regarded as a positive response to inhaled bronchodilator. In some cases, with minimal bronchial obstruction all the indices after bronchodilator inhalation reach the limit of normal, and the increase in FEV1 of less than 190 ml. Then, if established cooperation patient and physician, and a satisfactory reproducibility of flow-volume curve during the initial investigation of such a test can be assessed as positive.
Airway inflammation accompanied by bronchial hyperreactivity, which are used for the diagnosis of provocation tests with histamine and methacholine. To study bronchial hyperreactivity (SAB), there are several methods, the choice of which depends on the equipment: Adjust gradually increased doses of methacholine (histamine) occurs by inhalation of a constant volume of air and varying the aerosol concentration or increase the dose by increasing the inhaled Viagra help with premature ejaculation volume at a constant concentration. At the last method of action is based device "Pariprovotest-2" (company "Pari, Germany). As the gun is used a nebulizer, as shown by studies with labeled with radio-labeled aerosols aerosol particles less than 2.3 microns in diameter reach the lower respiratory tract. In "Pariprovoteste-2, unlike the first model, the solution is applied methacholine (histamine), one concentration (0.33%), which not only cost effective but also reduces the time of the study. After each inhalation spend-control study of forced expiratory flow, test terminated when the fall in FEV1 of 20% or more of the basic values for which the accepted value of FEV1 after inhalation of the solvent provocative agent (in the case of methacholine - saline). Calculate the cumulative dose of substance, ie dose (PD20), resulted in a decline OFV1na 20% [3]. The evaluation bronhoprovokatsionnyh samples to identify the degree of hyperresponsiveness, hypersensitivity accounting and comparing the results with other studies it is important to calculate the PD20, although ecological studies allowed the use of PD10.
You should not assign bronhoprovokatsionnye tests to differential diagnosis: today there is no inflammatory agents, allowing to clearly differentiate asthma and other chronic lung diseases that occur with bronchoobstructive syndrome. Conducting tests with methacholine provocation (histamine) is usually shown in children with long-term remission of asthma, in some cases (in normal parameters of ERF) - to establish the severity of the disease, since there is relation between the degree of bronchial hyperresponsiveness to the severity of the disease. Change a positive response to inhalation of a provocative agent to negative after treatment, or reduction in the degree of bronchial hyperreactivity, of course, indicates the effectiveness of prescribed therapy. In chronic nonspecific inflammatory lung diseases, as shown by our study, almost half of the patients is determined by bronchial hyperreactivity, but its degree is usually low, much less - an average, a high degree of SAB, we have not seen once.
Test with dosed physical exercise is widely used in children with bronchopulmonary diseases. Testing is conducted on a bicycle ergometer at the rate of 1 watt per 1 kg of body weight at 60-70 cadence of 1 minute, you can also use the treadmill, in this case, the load is determined depending on the child's age [1]. Most researchers evaluate the test as positive at lower values of FEV1 by 10% after exercise. Studies have shown that there is a direct correlation between the frequency of occurrence poslenagruzochnogo bronchospasm and severity of asthma. In addition, poslenagruzochny bronchospasm often diagnosed in patients who complained of shortness of breath during physical activity [4]. Significant correlation between the detection poslenagruzochnogo spasm and bronchial hyperreactivity available evidence does not exist [5]. In this regard, the choice of the complex functional studies is determined not only with appropriate equipment, but also the terms of the problems that have to solve the practical physician.
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