Exhaled breath condensate in children: present knowledge and future prospects

Exhaled breath condensate (EBC) is a safe and easy technique that enables several biomarkers of lung disease to be detected. Condensate collection requires only minimal cooperation and can easily be done by children as young as 4 years old. Some condensers have been adapted for use by younger children but EBC collection with these devices still poses significant drawbacks. EBC has been applied in the study of various respiratory diseases in children (mostly asthma and cystic fibrosis, but also other diseases such as primary ciliary dyskinesia). Several biomarkers of airway inflammation and oxidative stress have been detected in the EBC of these patients, demonstrating the role of different inflammatory pathways in the pathophysiology of respiratory diseases. Lately EBC has also been analyzed using new techniques, such as metabolomic analysis, an approach that enables the simultaneous assessment of several biocompounds with the potential identification of metabolite profiles characteristic of a given disease. Studies published so far support the promising role of EBC in investigating the pathophysiology of lung diseases. The noninvasiveness of this technique makes it particularly suitable for application in children.