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 FEV(1), FVC, PEF, FEV(1)/FVC ratio and the Moment Ratio, while those which became abnormal earlier were FEV(1), FEV(1)/FVC, MEF(50), and the first moment. Additionally, the tests that became abnormal in a higher proportion of patients were MMEF, MEF(50), MEF(75), and the first moment. CONCLUSIONS: The results o thi 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. KEYWORDS: obliterative bronchiolitis, lung transplantation, moments analysis, airway function tests, total lymphoid irradiation

Comparison of the functional results of single lung transplantation for pulmonary fibrosis and chronic airway obstruction.

BACKGROUND: Single lung transplantation (SLT) is now a treatment option for patients with both pulmonary fibrosis and advanced chronic airway obstruction. Lung function after transplantation might be expected to be different in these two groups of patients because of the effect of the remaining native lung, but the implications of these differences have not been fully explored. METHODS: The functional results of a stable population of 20 patients (13 chronic airway obstruction, seven pulmonary fibrosis) after SLT with no evidence of obliterative bronchiolitis were analysed. The differences between the two populations in the interrelations between and determinants of total lung capacity (TLC), subdivisions of lung volume, airway function (spirometry, maximum expiratory flow volume curves, and moments analysis of the spirogram) respiratory mechanics (PV curves and maximal respiratory pressures), CO transfer factor (TLCO) and the distribution of perfusion, ventilation and volume of the transplanted and native lungs were compared. RESULTS: Total lung capacity after SLT (TLCpost) was normal in the patients with pulmonary fibrosis (mean (SE) 103.9 (6.9)% predicted) but remained significantly elevated in patients with airway obstruction (126.4 (4.4)%. Forced expiratory volume in one second (FEV1) and vital capacity (VC) improved to similar values after SLT in both groups with a final VC of 76.8 (5.9)% and 66.7 (3.9)% in patients with fibrosis and airway obstruction, respectively. Maximum expiratory flows were generally lower and moments analysis of the spirogram showed slower lung emptying with significantly greater second and third moments (alpha 2 and alpha 3) in patients with airway obstruction. Relative ventilation and perfusion of the transplanted lung were both greater in both populations but relative ventilation of the transplanted lung was significantly greater in patients treated for airway disease than in those with pulmonary fibrosis. TLCO was also significantly higher in patients who had received a transplant for chronic airway obstruction. CONCLUSIONS: These results suggest that differences in the functional results of SLT for airway disease and pulmonary fibrosis are relatively minor. In this series the native hyperinflated lung in chronic airway disease was not more disadvantageous to overall function than the native lung in pulmonary fibrosis. However, tests of lung function based on the terminal portion of the forced spirogram are likely to be less sensitive for the detection of obliterative bronchiolitis in patients who have received a transplant for advanced airway obstruction than in those with pulmonary fibrosis.

Respiratory mechanics after heart-lung and bilateral lung transplantation.

BACKGROUND: The factors determining respiratory mechanics following heart-lung transplantation (HLT) and bilateral lung transplantation (BLT) are incompletely understood. METHODS: The dynamic and static lung volumes of 15 patients after HLT (n = 6) and BLT (n = 9) with no evidence of obliterative bronchiolitis were analysed to assess the factors which determine lung volumes following transplantation. Post-transplantation total lung capacity (TLCpost) was compared with the size of the recipient's lungs (TLCpre), the predicted capacity of the thorax of the recipient (TLCpred), and the predicted size of the donor's lungs (TLCdon). In addition, the post-transplantation respiratory mechanics were investigated by measuring the static pressure-volume (PV) curve of the lungs and the maximum respiratory pressures in a subgroup of nine patients (four HLT, five BLT). RESULTS: TLCpost was closely related to TLCpred in both groups and showed no correlation with TLCpre. The mean (95% CI) TLCpost was 102.5 (90.2 to 115)% predicted for the recipient in the HLT group and 109 (97.6 to 120)% predicted for the recipient in the BLT group. Despite the near normal TLC, residual volume (RV) and functional residual capacity (FRC) remained increased after transplantation in both groups. These abnormalities were not attributable to either airflow obstruction or expiratory muscle weakness. On average, lung compliance expressed in terms of the shape constant of the static pressure-volume curve of the lungs was mildly reduced in both groups compared with values predicted for the recipient. CONCLUSIONS: These results suggest that at high lung volumes the chest wall adapts to the size of transplanted lungs, while at lower volumes the increase in FRC and RV might be due to a persistent change in the static pressure-volume curve of the chest wall.