ABSTRACT
DEFINITION A disorder characterised by airfl ow obstruction, which is usually progressive, not ➤ fully reversible and does not change markedly over several months. Airfl ow obstruction is defi ned as reduced FEV ➤ 1 (forced expiratory volume in 1 second) and a reduced FEV1/FVC (forced vital capacity) ratio such that FEV1 <80% predicted and FEV1/FVC <0.7.
