Effect of continuous positive airway pressure and upper airway surgery on exhaled breath condensate and serum biomarkers in patients with sleep apnea

INTRODUCTIONStudies on inflammation biomarkers in serum and in exhaled breath condensate (EBC) in obstructive sleep apnea (OSA) have shown conflicting results. The objective of this study is to assess EBC and serum biomarkers in OSA patients at baseline and after continuous positive airway pressure (CPAP) or upper airway surgery (UAS).PATIENTS AND METHODSNine OSA patients referred for UAS were matched for anthropometric characteristics and apnea-hypopnea index with 20 patients receiving CPAP. pH, nitrite (NO2(-)), nitrate and interleukin 6 in EBC and NO2(-), nitrate, leukotriene B4 and interleukin 6 in serum were determined. EBC and serum samples were collected at baseline and 3 months after CPAP or UAS.RESULTSPatients' mean body mass index was 30 (range 24.9-40) kg/m(2). EBC biomarker levels at baseline were within normal range and did not differ significantly after CPAP or UAS. No significant changes were observed in the serum concentration of the biomarkers determined after CPAP but the serum concentration of NO2(-) increased significantly at 3 months after UAS (P=.0078).CONCLUSIONIn mildly obese OSA patients, EBC biomarkers of inflammation or oxidative stress were normal at baseline and remained unchanged 3 months after UAS or CPAP. Although UAS was not effective in terms of reducing OSA severity, it was associated with an increase in serum NO2(-).