Airway Inflammation in Congenital Diaphragmatic Hernia Patients

Subject will inhale 5 mls of 3% hypertonic saline for 7 minutes by nebulizer. Sputum production (with cough) will be attempted post inhalation. A maximum of 3 hypertonic saline inhalations will be attempted if inhalation does not generate a productive cough. If sputum induction is not successful and the FEV1 falls \<10%, the concentration of inhaled hypertonic saline will increase from 3 to 4%. If 5 mls of 4% hypertonic saline inhaled for 7 minutes does not produce a productive cough we will proceed to 5%. If 5 mls of 5% hypertonic saline inhaled for 7 minutes does not produce a productive cough the test is complete and the sample is labelled 'no sputum collected'. If FEV1 falls \>10%, the previous step will be repeated.

A bronchodilator (Salbutamol 200 mcg or 2 puffs inhaled via spacer device) will be administered to all subjects in the pulmonary function laboratory. 15 minutes after administration of the bronchodilator spirometry will be repeated. This is performed routinely in CDH clinic and is not an additional test for this study.