Inert gas single-breath washout and structural alteration of respiratory bronchioles.
With the perspective of establishing a link between a respiratory function test and alterations of membranous bronchioles, respiratory bronchioles, and alveolar ducts, we performed forced expirations and four kinds of single-breath washout maneuvers on 27 men due to undergo a lobectomy for peripheral bronchial carcinoma. For the single-breath washouts, the inhaled gas mixture consisted of 90% O2, 5% He, 5% SF6. The four maneuvers were the standard vital capacity test and three successive inhalations of 0.5, 1, and 1.5 L from functional residual capacity. The slopes of N2, He, and SF6 for each maneuver were computed, as well as a new index (I2) describing the relative decrease of the difference between the SF6 and the He slopes induced by a larger inspiratory volume. The histologic analysis focused on pigmentation, inflammation, and fibrosis of membranous bronchioles, respiratory bronchioles, and alveolar ducts. There was a linear relationship with a highly significant correlation coefficient between the new index I2 and the degree of inflammatory (r = 0.73) and fibrotic (r = 0.63) changes of the respiratory bronchioles; this correlation persisted in patients with a normal FEV1/VC ratio. These preliminary data open the way to finding a test for early peripheral (intraacinar) airway dysfunction.
Van Muylem
A
A
Chest Service, Erasme Hospital, Brussels, Belgium.
De Vuyst
P
P
Yernault
J C
JC
Paiva
M
M
D000328:Adult; D000368:Aged; D001530:Belgium / Q000453:epidemiology; D001944:Breath Tests / Q000295:instrumentation / Q000379:methods*; D002283:Carcinoma, Bronchogenic / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology; D005069:Evaluation Studies as Topic; D005355:Fibrosis; D005541:Forced Expiratory Volume; D005652:Functional Residual Capacity; D006801:Humans; D007249:Inflammation; D016014:Linear Models; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D005741:Noble Gases; D010858:Pigmentation; D012115:Residual Volume; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
D005741:Noble Gases