Lung volume and interdependence in the pig

The effect of lung volume on the mechanical interdependence between an obstructed sublobar region of lung and its surroundings tissues was investigated in intact and isolated pig lungs. Interdependence is arbitrarily defined as the effectiveness with which the linkage between the region and surrounding tissue mediates a tendency for inflation to become even whenever it is uneven. When the volume of the surrounding lung (Vl) was high relative to the volume of the obstructed region (Vr), or when they were relatively equal at higher inflation states, interdependence decreased. When Vr was high relative to Vl, interdependence increased. From a consideration of the changes in regional shape observed during even and uneven inflation states it is suggested, that regional distortion and its effects on regional elastic recoil are important determinants of pulmonary interdependence.