To decide whether this treatment should be used throughout the NHS, we need to run a randomised controlled trial of hypertonic saline in a large number of children. The trial will tell us if adding saline to usual care reduces distress in both children and parents, as well as whether it reduces the length of time they stay in hospital. We will then know if the treatment is the best thing for children with bronchiolitis and whether it provides the NHS with good value for money.