Effect of short and long term antibiotic response on lung function in bronchiectasis.

In a study designed to show whether purulent bronchial secretions damage the lung reversibly or irreversibly, 18 patients with bronchiectasis underwent lung function tests before and after two weeks' antibiotic treatment to convert their sputum from purulent to mucoid, and 10 of them also after four months' treatment. After two weeks FEV1, forced vital capacity, vital capacity, functional residual capacity, and total lung capacity showed small but statistically significant (though not clinically useful) improvements. In the 10 patients studied after four months only FVC (of the four indices with significant improvements at two weeks in this group) was still higher than before treatment. These results contrast with those of an earlier study, in which large acute changes were found, perhaps because of differences in the patients studied. It is concluded that the absence of major changes in lung function points to physiological abnormality that is largely irreversible in these patients with chronic bronchial sepsis.