An Evaluation of Slow Vital Capacity and Forced Vital Capacity Difference in Aco Patients with Obesity

Abstract

While COPD is characterised by an accelerated, although variable FEV1 decline , many ACO patients experience a slow decline in lung function. Among subjects with ACO, FEV1/FVC ratio may miss airflow limitation. It remains unclear whether using SVC instead of FVC increases the detecting of airflow limitation in ACO patients with obesity.

Objectives: To investigate the differences between SVC and FVC in ACO patients with obesity.

Methods: Subjects (n=255) aged 50–64 years were investigated with FEV1, FVC, and SVC . All spirometric maneuvers were performed before and 15 minutes after inhalation of 400 μg of salbutamol. The 2005 ATS / ERS recommendations were used to evaluate the spirometric results.

Results: The main demographic indicators of the study cohort included 68% of men and 32% of women, with an average age of 58.7 years. The 23.4% of patients had preserved or mildly reduced obstruction, 38.7% moderate, 26.75%- severe and 11.2% had very severe obstruction . The most subjects diagnosed with airflow obstruction according to FEV1/ SVC only had mildly reduced FEV1. Among people with normal spirometry,22,4% had a SVC-FVC difference of more than 500 ml. Patients with BMI > 30 kg/m2 were associated with airflow obstruction diagnosed only by FEV1/ SVC.

Conclusions: Our research demonstrates great differences between FVC and SVC values . There is a greater difference between these indicators in subjects with preserved or mild obstruction This indicates that FEV1/SVC relation is the most reliable in the detection of an obstruction in ACO patients with obesity.