Physiotherapy and bronchial mucus transport.

Cough and expectoration of mucus are the best-known symptoms in patients with pulmonary disease. The most applied intervention for these symptoms is the use of chest physiotherapy to increase bronchial mucus transport and reduce retention of mucus in the airways. Chest physiotherapy interventions can be evaluated using different outcome variables, such as bronchial mucus transport measurement, measurement of the amount of expectorated mucus, pulmonary function, medication use, frequency of exacerbation and quality of life. Measurement of the transport rate of mucus in the airways using a radioactive tracer appears to be an appropriate outcome variable for short-term studies. Evaluation of chest physiotherapy only with pulmonary function tests appears to be inadequate in short-term studies. The popularity of using pulmonary function tests is probably based more on the availability of the instruments than on a theoretical basis related to the question of chest physiotherapy improving mucus transport. Quality of life and progression of the disease are not often used as outcome variables, but it may be worthwhile to use these in the future.