Pattern of diffusion disturbance in patients with interstitial lung diseases (ILDs)

Abstract

Aim: to classify diffusion disturbances in patients with ILDs in four patterns, using body plethysmography and single-breath carbon monoxide diffusing capacity (DLCO): the pattern of alveolar-capillary membrane damage (AMD), the pattern of air trapping (AT), the pattern of gas-exchanging surface reduction (GSR) and the pattern of mixed gas exchange abnormalities (MA).

Results: the parameters of DLCO and body plethysmography were analyzed in 336 patients with ILDs: 110 male (age M 45.3 SD 15.3 yr) and 226 female (age M 51.3 SD 12.3 yr). The alveolar volume (VA) is informative for the characteristic of gas-exchanging surface. Non-communicating gas volume (ΔTLC=TLCpleth–TLCHe) is informative for air trapping assessment. The AMD pattern (n=96) is defined as decreased DLCO, normal VA and ΔTLC. In this case membrane is damaged, but surface is still not reduced. Patients with AT pattern (n=75) have decreased DLCO, normal VA and increased ΔTLC. The GSR pattern (n=119) is defined as decreased DLCO, decreased VA and normal ΔTLC. Patients with MA pattern (n=46) have decreased DLCO, decreased VA and increased ΔTLC. Ventilation disorders and diffusion disturbance patterns correlate, but not determine each other. In patients with restrictive disorder GSR pattern was prevailed (67%). Almost half of the cases with obstructive disorder had AT pattern (49%). However, in normal, obstructive, restrictive and mixed ventilation disorder groups, all patterns of diffusion disturbance were detected.

Conclusions: Recognition of four patterns of diffusion disturbance in ILDs patients provides significant details to ventilatory disorder study and helps to determine the individual characteristics of the disease course.