forced expiratory volume FEV
forced expiratory volume FEVA measurement made with an instrument that measures expired air flow (a recording SPIROMETER). Forced expiratory volume is the maximum volume of air that can be breathed out in one second. The FEV is then compared with the maximum amount that can be breathed out in a single breath, however prolonged (the VITAL CAPACITY). The ratio FEV/VC should exceed 70% in healthy individuals but is much reduced in people with any condition that narrows the air tubes (obstructive airway disease), such as ASTHMA or chronic BRONCHITIS.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005