Can pepsin, a digestive enzyme normally found in the gastro intestinal tract, be found in the exhaled breath of people with idiopathic pulmonary fibrosis (IPF) and is nitric oxide present in excess amounts. How do these results compare with normal individuals and are results repeatable.

IPF subjects and age matched individuals (without respiratory disease or symptoms of gastroesophageal reflux (GER)) will perform an exhaled breath condensate manoeuvre on 3 consecutive weekdays from which measurements of pepsin and nitric oxide will be made. • EBC collection: Collection will occur using a proprietary device including a saliva trap (R-tubes, Respiratory Research, Austin Texas) using established techniques. • Patients will be fasting for 3hr for food and 2h for water; avoid alcoholic drinks, coffee and other food or beverages containing caffeine (cola, tea, cocoa) for at least 3 h before the examination. They should also abstain from foods containing nitrates (lettuce, spinach, cabbage, sausages) and high-fat foods for at least 12h before the examination. • Collection will take place over 10 minutes with the subjects sitting comfortably upright and exhaling through the cold R-tubes (chilled to -20degC) • Collection time will be standardised to be between 9 and 10 am