Predicted values were calculated using the equations of Knudson and colleagues (1976). The sputum expectorated within a 24-hr period was collected in a plastic flask by the participants and weighed on an electronic scale. The amount of sputum expectorated during a session of airway clearance techniques was collected independently in

a separate flask, so that it could be calculated as a proportion of the 24-hour sputum weight. Oxygenation was measured using a standard pulse oximeter with a finger probe. Stable readings were required for 10 sec before recording the data. Oxygenation was also continuously monitored during the exercise test (described below) to determine the greatest reduction during the exercise Palbociclib molecular weight test. Exercise capacity was measured using the original 10-m shuttle test (Singh et al 1994) or the Multi Stage Fitness Test (Léger and Lambert 1989). Oxygen uptake at peak exercise was estimated from the exercise testing using standard equations (Singh et al 1994, Léger and Lambert 1989). Participants SB431542 molecular weight completed the adult Australian Cystic Fibrosis Quality of Life (CFQOL) questionnairec independently. This questionnaire results in an overall score between 0 (worst) and 100 (best). A change in FEV1 of 10% is used as a threshold for Australian

government reimbursement of the cost of dornase alpha. We therefore nominated 10% as the between-group difference we sought to identify. Assuming a within-patient SD of 10%, 18 participants would provide 80% power, at the 2-sided 5% significance level, to detect a 10% difference in FEV1 between the experimental and control arms as statistically significant. We recruited 20 participants to allow for loss to follow-up. Continuous data were summarised as means and standard deviations and categorical data

were summarised as frequencies and percentages. The normality however of the distribution of the data was examined with the Kolmogorov-Smirnov test. Although some of the raw data were not normally distributed, the within-subject differences were normally distributed. Therefore the data were analysed using parametric statistics. Between-group differences in change from baseline were analysed using paired t-tests. Mean differences (95% CI) between groups are presented. Data were analysed by intention-to-treat. The effect of the timing regimen on FEV1 was correlated against baseline FEV1 and against baseline sputum production, and the strength of the relationship was reported using the coefficient of determination (r2). Thirty adults from the Cystic Fibrosis Unit were screened for eligibility. Twenty met the initial eligibility criteria, but three withdrew during the 14-day period of regular use of airway clearance techniques, citing time constraints.