Serial changes in pulmonary functions in children hospitalized with cystic fibrosis.

Pulmonary functions were serially measured in 17 children hospitalized with cystic fibrosis (CF) to determine how much and when pulmonary functions improved during 14 days of inpatient treatment. Absolute lung volumes and forced expiratory flows were recorded every other day while patients received chest physiotherapy, antibiotics, and bronchodilators. Vital capacity first improved after the fifth hospital day coincidentally with a reduction in residual volume and an increase in peak expiratory flow rate. Significant improvements in other pulmonary functions developed later in the hospitalization. Improvement in most pulmonary functions continued throughout the hospitalization and was maintained 2 wk after discharge. Improvement was less and uniformly developed later in those children with severe lung disease on admission (NIH score less than 50) compared with those with moderate respiratory involvement (NIH score greater than 50). Pulmonary function measurements may prove useful in determining the optimal duration of treatment for patients who are hospitalized with CF.