The bronchitis index. A semiquantitative visual scale for the assessment of airways inflammation

Flexible fiberoptic bronchoscopy has been proven to be an effective tool for the assessment and characterization of airway inflammation. Visual inspection of airways affected by chronic bronchitis discloses an abnormal appearance characterized by erythema, edema, secretions, and friability. It was hypothesized that the visual appearance of airway inflammation could be assessed in a semiquantitative manner. A bronchitis index (BI) was developed that scores the visual appearance of airways according to the presence or absence of abnormal edema, erythema, secretions, and friability (0 = normal, 3 = remarkably abnormal). The BI was determined in three study groups: 86 subjects with chronic bronchitis, 15 subjects who smoked cigarettes, but did not have chronic bronchitis, and 25 normal, nonsmoking control subjects. The reproducibility of the BI was determined by comparing the results from pairs of two independent observers assessing 249 subjects undergoing fiberoptic bronchoscopy under various investigative protocols. In total, nine investigators scored the airways. For the three observer pairs with more than six observations, there were no differences noted in the BI (p = 0.43, 0.67, 0.82). To control for the effect of cough upon the BI, lidocaine usage was recorded. No correlation was found between lidocaine usage and BI. As previously noted for a smaller group of subjects, the BI was found to be elevated in those with chronic bronchitis (13.2 +/- 0.53) compared with both asymptomatic smokers (8.5 +/- 0.89, p < 0.0005) and normal volunteers (2.3 +/- 0.55, p < 0.0001); the latter two groups also differed significantly (p < 0.0001). The BI was also found to correlate significantly with bronchial sample lavage fluid neutrophil content in lavage fluid obtained after determination of the BI and with cigarette smoking as quantitated by pack years. Conversely, the BI correlated negatively with the spirometric measures of airway obstruction, FEV1, FEV1/FVC, FEV25-75, and FEFmax. Thus, the BI appears to be a reproducible, semiquantitative assessment of the visual appearance of airway inflammation. It may be a useful bronchoscopic adjunct for the assessment of airway inflammation in clinical investigations.