Respiratory muscles are essential to alveolar ventilation. There is accumulating evidence that inspiratory muscle function is abnormal in chronic obstructive pulmonary disease (COPD). Moreover, the inspiratory muscles face an increased elastic and resistive load in COPD. The imbalance between the function of the inspiratory muscles and the load they are facing plays an important role in the genesis of dyspnea<sup>1 Dyspnea Mechanisms, assessment, and management: A consensus statement: American Thoracic Society Am J Respir Crit Care Med 1999 ;  159 : 321-340

Cliccare qui per andare alla sezione Riferimenti</sup> and hypercapnia.<sup>8 Bégin P., Grassino A. Inspiratory muscle dysfunction and chronic hypercapnia in chronic obstructive pulmonary disease Am Rev Respir Dis 1991 ;  143 : 905

Cliccare qui per andare alla sezione Riferimenti, 82 Rochester D.F. Respiratory muscle weakness, pattern of breathing, and CO₂ retention in chronic obstructive pulmonary disease Am Rev Respir Dis 1991 ;  143 : 901

Cliccare qui per andare alla sezione Riferimenti, 90 Scano G., Spinelli A., Duranti R. , e al. Carbon dioxide responsiveness in COPD patients with and without chronic hypercapnia Eur Respir J 1995 ;  8 : 78  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> It has also been suggested that inspiratory muscle force could be an important determinant of survival in hospitalized patients with severe COPD.<sup>46 Gray-Donald K., Gibbons L., Shapiro S.H. , e al. Nutritional status and mortality in chronic obstructive pulmonary disease Am J Respir Crit Care Med 1996 ;  153 : 961

Cliccare qui per andare alla sezione Riferimenti</sup> This article reviews the mechanisms of inspiratory muscle function impairment in COPD and the secondary adaptations occurring in muscle structure and drive to which they are submitted.