Theoretical and Methodological Aspects of Body Plethysmography and Clinical Applications

Abstract

One of the methods to evaluate lung function is body plethysmography. Body plethysmography allows to measure indicators that cannot be obtained during spirometry, that is: total lung capacity (TLC), bronchial resistance (Raw), and functional residual capacity (FRC). FRC measured by body plethysmography reflects thoracic gas volume (TGV or VTG), and includes both ventilated and poorly ventilated volume. Plethysmographic measurements are based on the principle of the relationship between pressure and volume at constant temperature and fixed amount of gas. This principle states that the absolute pressure exerted by a given mass of an ideal gas is inversely proportional to the volume it occupies if the temperature and amount of gas remain unchanged within a closed system (Boyle-Mariotte Law). In body plethysmography, the following parameters: TGV, vital capacity (VC), expiratory reserve volume (ERV), tidal volume (TV), inspiratory reserve volume (IRV), inspiratory capacity (IC), Raw are obtained. TLC, residual volume (RV) and its share in total lung capacity can be calculated. Reduced TLC allows to diagnose restrictive disorders of pulmonary ventilation. The RV and its share in TLC increase together with airway obstruction indicates air trapping. The TGV increase together with airway obstruction indicates hyperinflation. In the analysis of lung volumes predictive values, which are calculated by the formulas recommended by ATS/ERS statement, are used. The results are expressed as a percentage of the predicted value. Thus, body plethysmography is an important addition to spirometry and image methods of research, allowing to assess the functional state of the lungs more objectively; it helps to conduct the differential diagnosis and control the course of the disease.

Specificities of small airways dysfunction development in patients with mild asthma

“…We observed normal values of TLC in all subjects, but it was statistically significantly higher in Group 2 than in the control group (Table 2). Thus, the results of our study have confirmed that IC values allowed for indirect estimates of intrathoracic volume or FRCplet, which complied with the literature data [10]. The IC values decline with the development of a lung hyperinflation, while TLC remains within its normal range or increases.…”

“…Asthma was diagnosed sensu the classification and the criteria of the international consensus on asthma diagnosing and treatment (GINA) [10]. The criteria for partly controlled asthma were the presence of one or two of the following symptoms over the past four weeks: daytime asthma manifestations more than twice a week; nighttime awakening caused by asthma; taking short-acting β2-agonists (bronchodilators) more than twice a week; any restrictions of activity due to asthma.…”

“…The criteria for partly controlled asthma were the presence of one or two of the following symptoms over the past four weeks: daytime asthma manifestations more than twice a week; nighttime awakening caused by asthma; taking short-acting β2-agonists (bronchodilators) more than twice a week; any restrictions of activity due to asthma. The ACQ-5 test (Asthma Control Questionnaire) was used to determine the level asthma management; the scores ranged 0.75-1.5, which implied the presence of partly controlled asthma [10].…”

Topical Issues of Clinical Application of Spirometry

“…Снижение ЖЕЛ (ФЖЕЛ) при исследовании в динамике указывает на необходимость активной терапии или коррекции проводимого лечения саркоидоза [12]. [6,9].…”

Single-breath diffusion capacity of the lungs for carbon monoxide in children with cystic fibrosis: methods of interpreting results

“…Результатом исследования диффузионной способности легких по монооксиду углерода (СО) является определение двух основных показателей: диффузионной способности легких (DLCO-SB, Single breath diffusing capacity for CO) и отношения этого показателя к доступному для исследования альвеолярному объему (VA-SB, alveolar volume) -DLCO/VA, который, в свою очередь, принято обозначать KCO. Последний показатель позволяет оценивать газотранспортную способность единицы альвеолярного объема, VA-SB -это показатель, который также определяется в ходе проведения исследования диффузионной способности легких при помощи физиологически инертного газа (гелия или метана) [3]. В клинической практике у детей показатели СПМ и БПГ, DLCO-SB и KCO-SB часто оцениваются в процентах по отношению к должным значениям (%Д), а сниженным считается показатель < 80 %Д [4,5].…”