Use of Volumetric Capnography in Submaximal Exercise Test: What Did We Learn?

Abstract

Tools that assess the response of the body to exercise activities have been sought in numerous clinical situations. Chronic obstructive pulmonary diseases such as cystic fibrosis (CF) may lead to reduction or limitation in exercise performance by ventilator factors. Consequently, a reduction in lung function can be observed, characterized by decreased respiratory reserve and dynamic hyperinflation during exercise. Various instruments have been developed and studied in thepediatricpopulation in order to evaluate the functional capacity during exercise, being grouped into maximal tests and submaximal tests. The difference between maximal and submaximal tests depends on whether the test is performed in an open area or laboratory, with ergometers or not. In the maximal test, the individual performs the activity to achieve voluntary exhaustion, leading the participant to the fullest of their oxygen uptake and/or estimated (more than 90%) heart rate (HR). In the submaximal tests, the HR is located around 75% to 90% of the maximum estimated HR. In the study, we used a reproducible exercise test protocol in accordance with the pediatric age group. We used the VCap, as an evaluation feature for lung function in children and adolescents with CF and with various degrees of severity of lung disease. We have identified the inhomogeneity of distribution of ventilation in the peripheral airways of patients with normal spirometry. Our findings collaborate with the idea that the VCap is a respiratory assessment tool that is practical, inexpensive and easy to use. The VCap provides information on the pulmonary involvement by the indices and is considered an assessment tool of the degree of regional heterogeneity of the lung for gas exchange. Thus, the VCap is a tool that can be used for analysis of ventilatory efficiency during exercise, providing evidence that the cardiorespiratory response that can be measured non-invasively during exercise testing.