[Lung transplantation and respiratory function tests. Functional outcome in the presence and absence of chronic...

Between may 1988 and march 1993, twenty five double lung transplants were performed and five heart/lung transplants. Lung function tests (EFR) were performed on these patients for a period of 19.2 +/- 3.4 months. The aim of this study was two-fold. First, to report our overall results and to estimate the role of the single breath nitrogen washout test (N2 slope) in the early detection of chronic rejection (RC). Secondly, to assess the diagnostic value of EFR in the discrimination of acute rejection (RA) and of cytomegalovirus pneumonitis (PCMV). There were 41 episodes of RA and 21 episodes of PCMV and they were analysed as a function of the presence or absence of RC. In the absence of RC, RA produced no change in EFR and PCMV was accompanied by a pure restrictive ventilatory defect. On the otherhand, RA and PCMV lead to a worsening of obstruction and an hypoxaemia which characterises RC. The diagnosis of RC was made, on average, 14.4 +/- 2.9 months after surgery. However, from the sixth month the nitrogen slope was significantly increased and other parameters of EFR (particular maximal flows at low lung volume) remained normal. Thus, our results suggest that the N2 slope, measured in the absence of any evidence of acute rejection, constitutes an early test for chronic rejection. When its pathological rise is compared to the results of histology (presence or absence of RC), it shows a sensitivity of 0.94 and a specificity of 0.93.