FUNCTIONAL CORRELATIONS WITH MILD AND MODERATE EMPHYSEMA IN EXCISED HUMAN LUNGS

Abstract

The relation between mild to moderate emphysema and lung function tests, including tests reported to identify early or mild disease, was examined in 24 excised human lungs, 5 with no emphysema, 11 with grade 5 or less emphysema and 9 with as much as grade 50 emphysema. Static pressure-volume curves, single-breath N2 (SBN2) tests, maximal expiratory flow-volume (MEFV) curves with air and a mixture of 80% He and 20% O2 and forced expiratory volume in 1-s (FEV1) were measured in all lungs. Negative correlations were found (r = -0.489, P < 0.02) between the emphysema grade and the percent predicted static lung recoil at 50% of total lung capacity and the emphysema grade and the percent predicted FEV1 (r = 0.428, P < 0.05). There was no significant correlation between the grade of emphysema and the SBN2 or MEFV tests. Negative correlations were found between the elastic recoil, expressed as percent predicted, and the percent closing capacity (r = 0.486, P < 0.02), the percent predicted slope of phase III (r = 0.482, P < 0.02), and the percent predicted FEV2 (r = -0.619, P < 0.01). Mild to moderate degrees of emphysema are not correlated with SBN2 tests or flow-volume curves using air or He but are related toloss of elastic recoil in excised human lungs.