Inspiratory Capacity in Chronic Obstructive Pulmonary Disease: A Measure of Hyperinflation and Relation with Other Parameters – A Cross-Sectional Study

Abstract

Introduction: Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide. Lung hyperinflation or air trapping is the hallmark of COPD and the primary cause of dyspnea, poor quality of life, and advertent disease prognosis associated with the disease. Debates continue to rise against the use of forced expiratory volume 1 as the single-main evaluative parameter for patients with COPD. Inspiratory capacity (IC) together with spirometry on the other hand has been shown to be a dependable parameter that can indicate the presence and management of lung hyperinflation. Patients and Methods: This cross-sectional study included fifty patients of COPD presenting to the department of respiratory medicine. All patients underwent spirometry and 6-min walk test (6MWT). They were grouped according to the GOLD guidelines for airflow limitation, body mass index (BMI), 6MWT, BODE index, number of exacerbations (NoEs), COPD “ABCD” assessment tool, and IC. t-test and one-way analysis of variance were applied. Results: There were 37 males and 13 females. A positive correlation was found between IC and 6MWT and BMI (coefficient of 0.678 and 0.149, respectively). There was a negative correlation between IC and NoEs and BODE index (coefficient of − 0.257 and − 0.631, respectively). IC correlated strongly with the GOLD classification for airflow limitation and combined assessment of COPD. A statistically significant difference between pre- and post-IC values showed IC as the predictor of lung hyperinflation. Conclusion: IC can be used along with 6MWT, BMI, BODE index and NoE for the prognostication and management of COPD.