Change of Inspiratory Peak Flow After Bronchial Dilatation on Patients With Moderate to Severe COPD

Chronic obstructive bronchitis and emphysema (COPD) are pathophysiologically characterized by inflammatory and structural changes in the lung. These changes lead to a reduction in elastic recoil as well as reduction in lung parenchyma. As a consequence collapse of the small airway occurs during expiration leading to expiratory flow limitation. In severe cases this flow limitation occurs even during resting condition. This expiratory collapse is suspected to mask changes in bronchial smooth muscle tone, especially if these changes in bronchial smooth muscle tone are assessed using expiratory manoeuvres. This might leave the impression of non-reversible airway obstruction und ineffectiveness of treatment with bronchodilators. Several studies suggest that in patients with COPD symptomatic changes following application of a bronchodilating compound do not correlate with changes in forced expiratory volumes. In contrast inspiratory lung function parameters (especially forced inspiratory volume in one second (FIV1)) is much more associated with symptomatic changes in patients with COPD. Comparable effects were also detected regarding peak inspiratory flow (PIF) values.Changes in inspiratory parameters following administration of a bronchodilator in patients with COPD and asthma are reproducible. PIF can easily be measured by inspiratory peak flow meters. So far no data exists on the usability of these devices following bronchodilation in patients with COPD. Formoterol is a rapid acting bronchodilator, which has been proven save in asthma and COPD