To study ventilation-perfusion ratio (VPR) in patients with chronic obstructive pulmonary disease (COPD) using method of volumetric capnography.
The article provides information on the lung dead space – a part of the respiratory volume that does not participate in gas exchange. The anatomical and alveolar dead spaces jointly together form the physiological dead space. The article describes methods for determining the volume of dead spaces using the capnovolumetry. The volume of physiological dead space is calculated using the C. Bohr equation. The volume of anatomical dead space can be determined using the equal area method proposed by W.S. Fowler. The volume of the alveolar dead space is the difference of volumes of the physiological and anatomical dead spaces. In pathology, the volume of the alveolar space and, consequently, physiological dead space can increase significantly. Determination of the volume of dead space is the significant criterion for diagnostic and predicting the outcome of a number of diseases. Keywords: Physiological dead space , anatomical dead space , alveolar dead space , capnovolumetry, volumetric capnography.
Respiratory system maintains a close contact with the environment and is constantly exposed to numerous pathogenic factors. In response to action of pathogen, different strategies of specific and non-specific defense have been formed: barrier functions of the epithelium, defense reflexes (coughing, sneezing), muco-ciliary clearance, resident and recruited cells, secretion of a number of proteins and peptides with protective functions. Aim. To systematize modern concepts of the protective mechanisms of lungs on the basis of the data of the relevant literature. In the work, the mechanisms and clinical significance of muco-ciliary clearance, resident alveolar and recruited macrophages, epithelial cells, neutrophils, lymphocytes and platelets are analyzed. Conclusion. The presented mechanisms can counteract the action of various pathogenic agents with sufficient effectiveness. However, in some cases an organism develops insufficient, excessive or perverted response to permeation of pathogens. This results in damage to the lung tissue by exogenous agents and/or by self immune system. Knowledge of protective mechanisms realized in the respiratory system, is necessary for understanding pathogenesis of respiratory diseases and for choice of the optimal treatment tactics.
Frustration of ventilation-perfusion ratio (VPR) plays a key role in changes of gas composition of the arterial blood in lung diseases. In the article the concept of VPR is presented; mechanisms of formation of ventilation, perfusion and VPR gradients in healthy lungs are described. Factors that provoke a mismatch between ventilation and perfusion in diseases of respiratory organs: pa- ВЕНТИЛЯЦИОННО-ПЕРФУЗИОННОЕ ОТНОШЕНИЕ В НОРМЕ И ПАТОЛОГИИ
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