Post-mortem lung volumes.

The volumes of 78 adult human lungs at necropsy after fixation with intrabronchial 10% formaldehyde at a transpulmonary pressure of 25 cm of water (VL) were similar to their total lung capacity (TLC) as assessed radiologically (VX). Corrected for stature, VL and VX did not increase with age in non-emphsematous lungs, nor did the radio of VL to VX (VL/VX) change with age. VL and VX relative to body length increased with emphysema, and the increase even occurred in lungs from men with trivial or equivocal amounts of emphysema. Thus alteration of the mechanical properties of the lung may precede the appearance of obvious emphysema. VL/VX was not affected by the presence or severity of emphysema. The right lung formed 53% of VL with a range of 49-58% in apparently normal lungs. The amount of air in 13 human lungs at necropsy averaged 61% of TLC with a wide variation, indicating that this is not a useful point at which to measure lung dimensions. It is concluded that the volume of lungs fixed with formaldehyde at a transpulmonary pressure of 25 cmH2O closely approximates to total lung capacity.