- Paper Report
- Open Access
Suck provides a better index than blow
- Richard Robbins1
© Biomed Central Ltd 2001
- Received: 18 August 2000
- Accepted: 19 September 2001
- Published: 19 September 2001
- Chronic obstructive pulmonary disease, COPD, dyspnea, pulmonary function testing, inspiratory force
Expiratory airway collapse is a characteristic feature of patients with (COPD). The authors hypothesized that this collapse would mask the effects of bronchodilators during forced expiration but not during forced inspiration, and that, accordingly, the improvement in forced inspiration and not that in forced expiration with bronchodilator therapy would be related to changes in the perception of dyspnea.
The authors conducted lung function measurements, including measurements of forced inspiration and expiration before and 30 min after inhalation of 400 μg salbutamol, in 61 patients with COPD and performed expiratory and inspiratory spirometry. The change in dyspnea from baseline was assessed with a standard visual analogue scale.
Salbutamol induced an improvement of 0.16 ± 0.02 L (mean ± SD) in FEV1, 0.36 ± 0.04 L in FIV1, 0.30 ± 0.04 L in IC, and -0.34 ± 0.07 L in intrathoracic gas volume. Factor analysis demonstrated that the reduction in dyspnea at rest was primarily associated with changes in parameters describing forced inspiration and not with those of forced expiration or lung hyperinflation, including IC.
The authors state that their data demonstrate that, in patients with COPD, the reduction in dyspnea after inhalation of a β2-adrenoreceptor agonist is closely correlated with the change in parameters of forced inspiration, and particularly FIV1, but not with changes in parameters of forced expiration or lung hyperinflation.
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Noseda A, Schmerber J, Prigogine T, Yernault JC: How do patients with either asthma or COPD perceive acute bronchodilation?
Eur Respir J 1993, 6:636-44
Similar study to that on which I have reported. Studied asthma and COPD subjects and suggests that dyspnea correlated best with specific inspiratory resistance. Concept is similar overall to the one discussed here.