Bronchoscopic validation of the significance of sputum purulence in severe exacerbations of chronic obstructive pulmonary disease

Publisher Website
Google Scholar
Abstract
Antibiotics are commonly prescribed in exacerbations of chronic obstructive pulmonary disease (COPD). However, the role of bacteria in these exacerbations is controversial. To identify clinical predictors of bacterial infection as a cause of exacerbation, considering the protected specimen brush (PSB) as the gold standard. Clinical data, sputum and PSB samples were collected from 40 patients with COPD requiring hospitalisation due to severe exacerbations who had not received previous antibiotic treatment. Quantitative cultures of PSB samples (n = 40) yielded 23 potential pathogenic microorganisms (PPMs) at concentrations of > or =10(2) colony-forming units/ml in 18 (45%) patients. Sputum samples were obtained from all 40 patients. Culture of good-quality sputum samples (n = 18) yielded 16 PPMs corresponding to 14 (35%) patients. The concordance between the PSB and sputum rate was high (kappa = 0.85, p < 0.002). The self-reporting patient observation of sputum purulence (odds ratio (OR) 27.20 (95% confidence interval (CI) 4.60 to 60.69), p = 0.001), the percentage predicted forced expiratory volume in 1 s (FEV(1)%) 4 exacerbations in the past year (OR 6.9 (95% CI 0.08 to 1.08), p = 0.028) and previous hospitalisations due to COPD (OR 4.13 (95% CI 1.02 to 16.07), p = 0.041) were associated with the presence of PPMs in the distal airways. The operative characteristics for predicting distal airway infection when patients presented with purulent exacerbation were as follows: sensitivity 89.5%, specificity 76.2%, positive predicted value 77.3% and negative predicted value 88.9%. The self-reporting presence of purulence in the sputum, as well as common previous exacerbations and hospitalisations due to COPD in patients with severe airflow obstruction (FEV1% <50) predict the presence of bacterial infection in the distal airways. The use of these clinical variables may help in selecting candidates to receive antibiotic treatment.