Among the 14 participants

who repeated the three-day study, perceived efficacy, tolerability, and satisfaction were very similar to those reported during the initial study (data not shown) and again no adverse events occurred. Eleven of the 14 participants preferred the same timing regimen as in the initial 3-day study. The proportions of participants in the ATR inhibitor repeat study who preferred each regimen were very similar to the initial study (see the first and last columns of Figure 2). This study identified that the timing of hypertonic saline in relation to airway clearance techniques did not have a substantial effect on the change in lung function after a single treatment session. However, participants were more satisfied with the entire treatment session when hypertonic saline was inhaled before or during the airway clearance techniques. Similarly, these timing regimens were also perceived as more effective than inhaling hypertonic saline after the techniques. These differences in perceived effectiveness and satisfaction Autophagy Compound Library solubility dmso may have important implications for long-term adherence, which is known to be low for both hypertonic saline and airway clearance techniques (Abbott et al 2004, Elkins et al 2006b). These results are likely to be valid because the

study design incorporated several features to minimise the potential for bias in the results, such as concealed allocation and intention-to-treat analysis. Also, sample size calculations for the primary outcome and one secondary

outcome were performed and the required cohorts were recruited. Furthermore, there was no loss to follow-up and compliance with the trial method was excellent. Potential bias was also reduced by blinding the assessors of the primary outcome. The stability of the results of this trial over time suggest that the initial results were not a chance finding. Hypertonic saline is known to cause a drop in lung function in some people with cystic fibrosis that typically resolves by 15 min but Modulators persists in a small percentage of patients (Bye and Elkins 2007). Therefore, one limitation of this study was that the effect of the timing regimen on lung function was only measured at 2 hours after baseline and not 15 min after Ketanserin the inhalation. However, trying to measure lung function immediately after inhalation would have interrupted the entire treatment session on some days and not others, and this may have confounded the comparisons between the timing regimens. Measurement was therefore standardised at 2 hours, allowing valid comparisons and providing important information about sustained treatment effects. Another limitation of the study was that measures of mucus clearance were not included, which reduces the potential to understand the mechanism(s) at work in the different timing regimens. However, any differences in mucus clearance were too small to produce substantial differences in lung function.