PULMONARY CAPILLARY BLOOD-VOLUME IN EMPHYSEMA

We determined single breath diffusing capacity (DL(CO)) and pulmonary capillary blood volume (Vc) in a total of 110 patients, who were being evaluated for resectional lung surgery for a localized tumor or lesion. Pathologic assessment of emphysema was obtained in 55 cases who had resection of a lung or an upper lobe, based on a standard reference panel for emphysema grading. In 86 cases, the extent of emphysema was quantitated by computed tomography (CT) of the chest. There was a significant negative correlation between Vc and emphysema assessed by either pathology or CT (r = about -0.5, p < 0.001) similar to the correlation between DL(CO) and the extent of emphysema. Results of Vc were significantly lower in cases with moderate emphysema (pathologic grade ≥ 30) than those with no emphysema (grade ≤ 5) (p < 0.001) or mild emphysema (grade 10 to 25) (p < 0.05), and they were significantly lower (p < 0.05) in the group with mild emphysema compared with the group with no emphysema on pathologic assessment similar to DL(CO) results. Although Vc was reduced in emphysema, determination of Vc did not result in improved discrimination in separating cases with emphysema from those without emphysema when compared with DL(CO).