Lung morphometry by unbiased methods in emphysema: bronchial and blood vessel volume, alveolar surface area and capillary length.

We have estimated lung volume, bronchial volume, vessel volume, alveolar surface area and capillary length in patients who died of lung failure due to emphysema and chronic obstructive pulmonary disease (COPD) and in patients with no clinical signs of respiratory disease. Unbiased morphometric methods were applied to the right lung. The patients with emphysema had equal lung volumes and bronchial and vessel volumes compared to the control group. The alveolar surface area and surface density were significantly decreased to about 67%, of control values. The capillary length and length density were significantly decreased to about 68% of control values. The proportional decreases in alveolar surface area and capillary length suggest that compensatory capillary proliferation has not occurred. These unbiased morphometric studies of emphysema have yielded results in end-stage emphysema that are comparable to those previously reported using biased methods. However, the unbiased methods may provide new insights when applied to earlier stages of the disease.