Assessment of hyperinflation in children with cystic fibrosis.

BACKGROUND Radiological estimates of hyperinflation are used in several clinical and radiographic scoring systems for cystic fibrosis, but it is not known if these estimates of hyperinflation are related to measured total lung capacity. METHODS Comparison was made of independent clinical estimates of hyperinflation from chest radiographs with objective plethysmographic and radiographic measurements of total lung capacity in 25 children with cystic fibrosis. RESULTS There was good agreement between plethysmographic and radiographic measurements. Clinical estimation correctly predicted the extremes of hyperinflation, but grading was no more than 50% accurate in all other groups. CONCLUSION The degree of hyperinflation cannot be estimated by inspecting chest radiographs in many children with cystic fibrosis. This does not invalidate the scoring systems, but suggests that a better term than "hyperinflation" should be sought.