Forced spirometry is a pulmonary function test in respiratory physiology that measures the volume-time curve of a maximal forced inspiration followed by maximal forced expiration, yielding two formal parameters: forced expiratory volume in one second (FEV1), the volume forcibly exhaled during the first second of expiration, and forced vital capacity (FVC), the total volume that can be forcibly inspired and expired. The diagnostic principle is the FEV1/FVC ratio expressed as a percentage, whose normal value is approximately 80%; because both terms share units, the ratio isolates airflow limitation from lung volume restriction. This concept sits within respiratory physiology and clinical pulmonology, linking the mechanical properties of lung elasticity and compliance to the classification of pulmonary disease as obstructive or restrictive.
Forced spirometry is a pulmonary function test in respiratory physiology that measures the volume-time curve of a maximal forced inspiration followed by maximal forced expiration, yielding two formal…