Although virtually all the participants in our study were colonised with

Pseudomonas aeruginosa, it did not demonstrate a clear advantage of inhaling dornase alpha after physical airway clearance techniques. In a different study, dornase alpha inhaled 30 min before physical airway clearance techniques improved expiratory flow at 25% of the forced vital capacity ( van der Giessen et al 2007). However, FEV1, FVC, and visual analogue scores of sputum and cough were not affected differently by the two timing regimens in that study. Although the other studies in this area reported the amount of sputum expectorated, ours was the only study to report the amount of sputum obtained during the airway clearance regimen as a proportion of daily sputum production. We believe this is an important measure because it reflects the immediate efficacy of airway Ceritinib concentration buy CHIR-99021 clearance interventions and the extent to which the person with cystic fibrosis will be productive of sputum throughout the remainder of the day when they may be undertaking work, study or social activities. On

average, about one-fifth of daily sputum production occurred during the airway clearance regimen. The correlational analyses we conducted confirmed that our overall result – the timing of dornase alpha inhalation had little effect on lung function – can be considered applicable to all people with cystic fibrosis who meet the eligibility criteria for this study. That is, the lack of an effect on lung function in this study was not due to a real effect in some participants being diluted or masked by a weak or adverse effect in participants with different characteristics such as baseline lung function or baseline sputum production. The knowledge that the timing of dornase alpha in relation to physical airway clearance techniques does not affect clinical outcomes is useful for patients and clinicians, because the regimen of dornase alpha can be prescribed according to other priorities. For most patients, the timing of dornase alpha in relation to airway clearance can be tailored

to patient preferences or timing in relation to other inhaled therapies. The correlation between change of quality of life scores and change in FEV1 suggests that the majority of patients can assess a true improvement subjectively. very N-of-1 trials may therefore be useful in determining a suitable timing regimen for an individual patient. In summary, the timing of dornase alpha inhalation does not appear to have a strong influence on the efficacy of the overall airway clearance regimen in adults with cystic fibrosis. The inhalation of dornase alpha can be prescribed according to convenience, patient preference, or to accommodate the timing of other medications in the treatment regimen. Ethics: The Western Sydney Area Health Service Human Research Ethics Committee approved this study, HREC 98/9/4.8 (695).