The objectives of the present study were to assess the level of exhaled breath markers indicating airway inflammation and oxidative stress in patients with obstructive sleep apnoea syndrome (OSAS) in comparison with non-apnoeic (obese and non-obese) subjects and investigate whether therapy with continuous positive airway pressure (CPAP) can modify them. The design was a retrospective observational study, set in Evgeneidio Hospital. Twenty-six OSAS patients and nine obese and 10 non-obese non-apnoeic subjects participated in this study. We measured nasal nitric oxide (nNO), exhaled nitric oxide (eNO), exhaled carbon monoxide (eCO) in exhaled breath, and 8-isoprostane, leukotriene B(4) (LTB(4)), nitrates, hydrogen peroxide (H(2)O(2)), and pH in exhaled breath condensate (EBC) before and after 1 month of CPAP therapy. The levels of eNO and eCO were higher in OSAS patients than in control subjects (p < 0.05). Nasal NO was higher in OSAS patients than in obese controls (p < 0.01). The level of H(2)O(2), 8-isoprostane, LTB(4), and nitrates were elevated in OSAS patients in comparison with obese subjects (p < 0.01). Conversely, pH was lower in OSAS patients than in non-apnoeic controls (p < 0.01). One month of CPAP therapy increased pH (p < 0.05) and reduced eNO (p < 0.001) and nNO (p < 0.05). Apnea/hypopnoea index was positively correlated with 8-isoprostane (r = 0.42; p < 0.05), LTB(4) (r = 0.35; p < 0.05), nitrates (r = 0.54; p < 0.001), and H(2)O(2) (r = 0.42; p < 0.05). Airway inflammation and oxidative stress are present in the airway of OSAS patients in contrast to non-apnoeic subjects. Exhaled breath markers are positively correlated with the severity of OSAS. One-month administration of CPAP improved airway inflammation and oxidative stress.

Although nasal surgery has limited efficacy in obstructive sleep apnoea (OSA) treatment, some patients experience improvement. The present study tested the hypothesis that post-surgery improvement is associated with increased nasal breathing epochs. A total of 49 OSA patients (mean apnoea/hypopnoea index (AHI) 30.1+/-16.3 events x h(-1)) with symptomatic fixed nasal obstruction due to deviated septum were randomly assigned to either septoplasty (surgery group; 27 patients) or sham surgery (placebo group; 22 patients). The breathing route was examined during overnight polysomnography. All patients in the placebo group were nonresponders, whereas in the surgery group four (14.8%) patients were responders and exhibited considerable increase in nasal breathing epochs (epochs containing more than three consecutive phasic nasal signals), and 23 patients were nonresponders, presenting a modest increase in nasal breathing epochs. The change in AHI was inversely related to the change in nasal breathing epochs, with responders exhibiting among the greatest increases in nasal breathing epochs. Baseline nasal breathing epochs were positively related to per cent change in AHI. Responders had among the lowest baseline nasal breathing epochs; a cut-off value of 62.4% of total sleep epochs best separated (100% sensitivity, 82.6% specificity) responders/nonresponders. In conclusion, nasal surgery rarely treats obstructive sleep apnoea effectively. Baseline nasal breathing epochs can predict the surgery outcome.

Although there is an association between nasal obstruction, oral breathing and obstructive sleep apnoea syndrome (OSAS), it remains unknown whether increased oral breathing occurs in patients with OSAS who are free of nasal obstruction. The present study evaluated the relationship between breathing route and OSAS in patients without nasal obstruction.The breathing route of 41 snorers (25 male; aged 26-77 yrs) with normal nasal resistance was examined during overnight polysomnography using a nasal cannula/pressure transducer and an oral thermistor.In total, 28 patients had OSAS (apnoeics) and 13 patients were simple snorers. Apnoeics had a higher percentage of oral and oro-nasal breathing epochs. Oral and oro-nasal breathing epochs were positively related with apnoea/hypopnoea index (AHI) and duration of apnoeas/hypopnoeas and inversely related to oxygen saturation. Additionally, oro-nasal breathing epochs correlated with body mass index (BMI). In multiple linear regression analysis, oral breathing epochs were independently related only to AHI (r 2 50.443), and oro-nasal breathing epochs were independently related to AHI (r 2 50.736) and BMI (r 2 50.036).In conclusion, apnoeics spent more time breathing orally and oro-nasally than simple snorers, and the apnoea/hypopnoea index is a major determinant of the time spent breathing orally and oro-nasally.

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