Clinical scenario

You see a 9-year-old girl with stable cystic fibrosis in your outpatient clinic and review her treatment regime with regard to lung function. Over the last 4 months she has been on nebulised recombinant deoxyribonuclease (rhDNase) 2.5 mg once daily, but her lung function has not shown any improvement. She has also had one pulmonary exacerbation requiring intravenous antibiotics over this period. You are aware that although rhDNase is widely used in the management of lung disease in cystic fibrosis, approximately 50% of patients may gain no clinically significant benefit,1,–,3 and studies have shown that response after a 3-month trial of therapy is a good predictor of longer term response.4 5 Given that your patient may be a poor responder to rhDNase, you wonder if treatment with nebulised hypertonic saline would improve pulmonary outcomes.