Chest physiotherapy and airway obstruction in patients with cystic fibrosis - a negative report.

In 24 patients with cystic fibrosis (6-20 years old), divided into two groups, we studied indices of airways obstruction before, 20-30 min and 2 h after chest physiotherapy. The physiotherapy lasted for 30 min and included expectoration of 2-10 ml of sputum. In one group of 14 patients, studies were made only 30 min after chest physiotherapy. No significant improvements of the ventilatory tests occurred. In fact, Vmax at 25% of VC deteriorated (P less than 0.05) in this group as a whole. In some patients also CV/VC increased, and N2 and CO2 alveolar slopes became steeper. Only Gaw/TGV improved in 20% of the patients by more than 10% of the control value. In the second group of 10 patients, ventilatory studies were repeated 3 times at one month intervals. They did not change significantly at 20 min and 2 h after chest physiotherapy. Gaw/TGV value improved by more than 10% in 20% of the patients. During chest physiotherapy, the patients were stimulated to cough. This might contribute to the immediate negative effects on ventilatory function by causing collapse of the central airways, as documented by cinebronchographic studies in 8 patients.