Restricted Pulmonary Function in Cystic Fibrosis: Conclusion

The results of serial pulmonary function tests from the previous (1983-84) and subsequent (1985-86) years also raises interesting questions about the mechanism of restriction and the implication of restriction regarding severity of disease. Three of nine restricted patients were no longer restricted on testing one year later, and two of eight were not restricted one year earlier. It is unlikely that the reduced plethysmographic pulmonary volume was due to measurement error, since nine of the ten restricted patients were restricted in at least two of the three years examined. In the nonrestricted patients, none of eight was restricted one year later, while two of eight were restricted one year earlier. Chest radiographic ratings did not change consistently over this period. Group data over one year of follow-up demonstrated a trend toward increase in expiratory flow and pulmonary volume in the restricted patients but not in the controls. These findings suggest that the restrictive process may be reversible in some patients and, therefore, does not necessarily represent an irreversible stage of disease. other

In summary, we conclude that restricted pulmonary function may be observed in some patients with cystic fibrosis. It does not appear to indicate more severe disease than a nonrestricted pattern and may be reversible in some patients. In addition, restriction detected by plethysmographic measurements of pulmonary volume may not be evident on radiographic measurements of thoracic cage volume. In some restricted patients, there is a large difference between radiographic measurements and plethysmographic or nitrogen-washout measurements of gas volume. In this study, these radiographic-gas volume differences were highly correlated in the restricted patients with radiographic evidence of air trapping (hyperinflation) and bronchial markings, but not with parenchymal lesions. Although the mechanism of the restrictive defect is unclear, these preliminary observations suggest a possible relationship to airway disease such as small airway obstruction.

Category: Pulmonary Function

Tags: airway, cystic fibrosis, Pulmonary Function