Volumetric Capnography to Assess Functional Respiratory Disturbances in Patients with Bronchial Asthma

Abstract

Ryazan State Medical University named after Academician I.P. Pavlov, Vysokovoltnaya St., 9, Ryazan, 390026, Russian Federation Spirometry, which implies carrying out forced expiration procedure, frequently, presents a problem, especially in patients with severe asthma, providing no idea of small airways condition. Volumetric capnography has no limitations typical for spirometry.The aim of the investigation was to study the capabilities of volumetric capnography to determine functional respiratory disturbances in patients with bronchial asthma.Materials and Methods. 171 male and female patients were examined, including 46 patients with severe bronchial asthma and 42 patients with moderate bronchial asthma. A control group consisted of 83 apparently healthy volunteers. All the subjects under study underwent a clinical examination. In addition, their spirometry and volumetric capnography findings were evaluated using an ultrasound computed spirograph SpiroScout (Ganshorn, Germany) capable of volumetric capnography. In addition, body plethysmography was carried out.Results. Volumetric capnography revealed the following changes in bronchial asthma patients compared to the controls: phase III inclination angle increase (g/mol·L), which indicates heterogeneity of lung periphery ventilation and perfusion due to small airways pathology, and an emphysema index characterizing pulmonary hyperinflation. Phase III inclination angle alterations were significant in different bronchial asthma severity degrees. A post-bronchodilator test with Salbutamol (400 µg) in the patients with bronchial asthma were found to show an increase in anatomical dead space (ml) and phase II inclination angle decrease (g/mol·L). Phase III inclination angle and an emphysema index of volumetric capnography demonstrated a correlation relationship with spirometry and body plethysmography parameters.Conclusion. Volumetric capnography extends the concept of the nature and degree of an impaired respiratory function in bronchial asthma. It enables to assess small airways function and determine the presence and extent of lung hyperinflation in patients with bronchial asthma.

Volumetric capnography versus spirometry for the evaluation of pulmonary function in cystic fibrosis and allergic asthma

“…In the present data, VCap was proven to be a useful instrument to differentiate patients with CF from healthy controls (on both adults and children) 6 , 13 and to differentiate children, adolescents, and adults with asthma from their healthy peers. 10 , 28 …”