Lung function in young adults with cystic fibrosis.

Pulmonary function tests have been carried out on eight adults with cystic fibrosis. There were statistically significant correlations between the severity of the patient's clinical state as assessed by the Shwachman score and TLco, TLC and VC. In addition the RV/TLC ratio increased with increasing clinical severity. There were no significant correlations between clinical severity and other measurements of lung function such as FEV1, PEFR, RV or PCO2. Serial studies indicated that the TLCO falls with increasing clinical severity of the disease. It is suggested that the objective measurements of pulmonary function should be included in any future 'scoring' system used to assess the severity of cystic fibrosis and that measurements of the single-breath TLCO might be one of the more discriminant tests.