Photo Credit: Svitlana Hulko
The following is a summary of “Inhomogeneity of ventilation in smokers and mild COPD assessed by the ratio of alveolar volume to total lung capacity,” published in the February 2024 issue of Pulmonology by Ovenholm, et al.
Previous research has highlighted the significance of the alveolar volume (VA) to total lung capacity (TLC) ratio in reflecting ventilation heterogeneity in individuals with chronic obstructive pulmonary disease (COPD). However, the relationship between this ratio and respiratory symptoms in subjects with mild chronic airflow obstruction or normal spirometry (normal ratio of forced expiratory volume in 1 second [FEV1] to vital capacity [VC]) remains unexplored. For a study, researchers sought to investigate the potential association between VA/TLC ratio and respiratory symptoms, smoking habits, and lung function parameters in subjects with normal spirometry and mild chronic airflow obstruction.
A cohort of 450 subjects (82 non-smokers with normal spirometry, 298 current or former smokers with normal spirometry, and 70 subjects with chronic airflow obstruction) underwent routine lung function tests and completed a questionnaire on respiratory symptoms.
Results revealed that among the subjects with a normal FEV1/VC ratio, 31 out of 54 individuals with a low VA/TLC ratio exhibited respiratory symptoms. Of these subjects, 58.1% reported respiratory symptoms, compared to 35.8% in the group with normal ratios for both VA/TLC and FEV1/VC (P-value 0.02).
In conclusion, the study demonstrated that within the subgroup of subjects with a normal FEV1/VC ratio, those with a decreased VA/TLC ratio had a higher prevalence of respiratory symptoms. The findings suggested that incorporating VA/TLC ratio assessment in pulmonary function testing may enhance the detection of individuals with early-stage or at-risk lung disease.
Reference: resmedjournal.com/article/S0954-6111(23)00412-2/fulltext