ABSTRACT
Chronic obstructive pulmonary disease (COPD) comprises a heterogeneous group of
conditions, characterized by chronic airflow limitation and parenchymal destruction
of lung parenchyma, with clinical manifestations of dyspnea, cough, sputum
production, and impaired exercise tolerance. The clinical course of COPD is one
of gradual progressive impairment, which may eventually lead to respiratory failure.
Periods of relative clinical stability are interrupted by recurrent exacerbations.
However, the definition of exacerbation is still imprecise and generally based on
varying combinations of symptoms such as an increase in cough or sputum
production, worsening of dyspnea, or changes in sputum purulence (1). An acute
exacerbation has also been described as a sustained worsening of the patient’s
condition, from the stable state and beyond normal day-to-day variations, that is
acute in onset and necessitates a change in regular medication in a patient with
underlying COPD (2). This imprecise definition of COPD, largely based on
experienced symptomatology by the patient without measurable parameters in
order to define severity or outcome hampers at present every systematic approach
of this disease condition. Based on the complexity of the sensation of breathlessness,
generally considered as a key symptom during exacerbations, it can hypothesized
AECOPD. Furthermore, considering an AECOPD as a sustained worsening of the
patient’s condition from the stable state and beyond normal day-to-day variations,
systemic effects can be considered as part of this baseline or stable condition.
