Markers in Exhaled Breath Condensate in Obstructive Sleep Apnoea (OSA) Patients

Patients with obstructive sleep apnoea (OSA) have repetitive episodes of partial or complete upper airway obstruction during sleep. This leads to sleep fragmentation and symptoms like excessive daytime sleepiness and impaired psychosocial well-being. More evidence now suggested OSA is associated with cardiovascular diseases like hypertension, myocardial infarction, pulmonary hypertension and stroke. The upper airway structure and function are altered in OSA. Some studies suggested that an increase in the levels of systemic biomarkers of inflammation and oxidative stress in patients with OSA. So far, there is only very limited data on non-invasive monitoring of inflammation involved in the upper airway of OSA patients. The inflammatory mechanisms involved in the upper airway may give some insights to the systemic effect, like cardiovascular complications, of OSA. Measurement of the constituents of exhaled breath and exhaled breath condensate (EBC) is a non-invasive method to assess the degree of inflammation of the airway. Exhaled nitric oxide (eNO) can be measured with the subject exhaling to a mouthpiece connected to a machine measuring real-time eNO level. With the subject exhaling to a cooling unit, EBC can be collected as liquid is formed as a result of condensation. This study will assess the eNO in exhaled breath, oxidative stress marker (8-isoprostane) and cellular inflammatory markers (eotaxin, monocyted derived chemokine, growth related oncogene- alpha, monocyte chemoattractant protein-1) in the EBC and blood of OSA patients before and after 1 night and 3 months of continuous positive airway pressure treatment.