[Functional study of the respiratory muscles in patients with diffuse interstitial pneumopathies (DIP)]

The aim of the study was to evaluate the function of the respiratory muscles in patients with diffuse interstitial lung diseases (DILD) by measuring the maximal static inspiratory (MIPS) and expiratory (MEPS) pressures and to find out a possible relationship between these pressures and some parameters of the respiratory function of the lung. The battery of functional tests consisted in: lung volumes, flow rates, lung elasticity and arterial partial pressure of oxygen at rest and on exercise. MIPS and MEPS were measured using the Black and Hyatt method. 82 patients with DILD of different etiologies were studied, 39 males and 43 females, with a mean age of 33.6 +/- 8.74 years. The results signaled the decrease of MIPS in 29 cases--35.3% (the mean value in % predicted and the standard deviation: 47.0 +/- 9.75) and of MEPS in 47 cases--57.3% (the mean value in % predicted and the standard deviation 49.7 +/- 9.3). No relationship has been found between the low values of MIPS and MEPS on one hand and the altered values of some parameters of the lung function (diminished lung volumes, increased elastic recoil, hypoxemia on exercise) on the other. The peak expiratory flow rate--PEF--was significantly greater in patients with normal values of MIPS and MEPS than in those with decreased ones, which confirms the dependence of PEF on the force of the respiratory muscles. In our study, despite previous published data, the decrease of the force of respiratory muscles in patients with DILD seems to appear with a rather high frequency.