ASSOCIATION BETWEEN ASBESTOS-RELATED PLEURAL PLAQUES AND RESTING HYPERVENTILATION

This study reports an association between pleural plaques and resting hyperventilation in a group of workers exposed to asbestos. Informatio n on exposure level, pack-years of cigarette smoking, chest radiograph s, ventilation parameters, single-breath diffusing lung capacity, and arterial gases were obtained for 344 workers. After the exclusion of 3 7 workers for isolated parenchymal fibrosis, combined pleuroparenchyma l fibrosis, or diffuse pleural thickening, 55 subjects with isolated p leural plaques were evaluated against 252 no-plaque workers. A quantit ative pleural score revealed mild pleural disease. Forty-four workers with plaques (80%) had hypocapnia induced by resting hyperventilation. The quantitative pleural score correlated significantly with the part ial pressure of carbon dioxide in arterial blood (correlation coeffici ent = -0.7). A decrement in forced vital capacity was associated with plaques, whether controlled for age, smoking, and exposure or not. It was concluded that the resting hyperventilation observed in some asbes tos-exposed subjects is related to the presence of mild pleural plaque s and a restrictive disorder.