ABSTRACT
By European consensus, COPD is defined as ‘‘a disorder characterized by reduced
maximum expiratory flow and slow forced emptying of the lungs; features which do
not change markedly over several months. Most of the airflow limitation is slowly
progressive and irreversible’’ (1). The most recently published world guidelines on
obstructive lung disease (GOLD) describe the airflow limitation as ‘‘associated with
an abnormal inflammatory response of the lungs to noxious particles or gases’’ (2).
Exacerbations of symptoms requiring medical intervention are important clinical
events in COPD. Infection and air pollution are important triggers, but the cause of
approximately one-third of severe exacerbations is unclear. Those in which infection
is identified show increases of sputum volume and change in its color; fever may
also be present.
