PhD defence I.G. (Iris) van der Sar

Brief summary: 

The group of interstitial lung diseases (ILD) includes >200 diseases affecting the lung interstitium. Patients have symptoms such as shortness of breath on exertion, coughing and fatigue. Most ILDs are rare with no clear cause, often chronic and progressive. The specific type of ILD is difficult to diagnose. After several additional investigations, the most likely diagnosis is determined in a meeting with several specialists. 

Exhaled breath contains volatile organic compounds (VOCs) that come from various (patho)physiological processes in the body or from (in)direct external influences. The total VOCs exhaled by a person (i.e. breath profile) reflects the health status. VOCs are analysed using gas chromatography-mass spectrometry (GC-MS) and electronic nose (eNose) sensor technology.
This thesis first provides an overview of technical details of the eNose and available scientific evidence. The second and third sections report the results of several studies in which diagnostic and screening applications of an eNose for diagnosing ILD were investigated in different hospitals. Positive results were found in all studies. Breathing profiles of various patient groups were found to be different with high accuracies. This indicates that in the future, eNose can facilitate diagnosis of ILD in patients with symptoms or at high risk of ILD. Also, eNose can hopefully reduce the need for invasive diagnostic procedures. 

Finally, VOCs from different groups of ILD patients were investigated by GC-MS. Unfortunately, the results could not be validated between hospitals. As a result, there seems to be no role for GC-MS analysis of exhaled air in differentiating ILDs.