Tests of airway function in detecting and monitoring treatment of obliterative bronchiolitis after lung transplantation

Background: This study evaluated different tests of airway function in detection of obliterative bronchiolitis. It included analysis of spirogram within the time domain in patients with and without obliterative bronchiolitis (OB) after heart lung and lung transplantation. The purpose of this analysis is to evaluate which tests are of greatest value for early recognition of OB. Methods: The coefficient of variation of different airway function tests was calculated in 13 patients who had no evidence of OB and 12 patients who developed OB post-transplantation. In the patients with OB the effect of treatment with total lymphoid irradiation (TLI) was investigated by comparing the rate of change of lung function before and after TLI. Several lung function tests were used. Results: The measurements that showed the least variation were FEV1, FVC, PEF, FEV1/FVC ratio and the Moment Ratio, while those which became abnormal earlier were FEV1, FEV1/FVC, MEF50, and the first moment. Additionally, the tests that became abnormal in a higher proportion of patients were MMEF, MEF50, MEF75, and the first moment. Conclusions: The results of this study support the use of simple spirometric indices for the detection of OB. In the patients with OB the rates of decline of lung function were significantly attenuated by treatment with TLI as determined by several different tests.