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Background: Upper airway inflammation is present in patients with obstructive sleep apnea (OSA)., Objective: To determine whether exhaled pentane and nitric oxide (NO) levels, two nonspecific markers of inflammation, are increased in patients with OSA., Methods: Exhaled nasal and oral pentane and NO levels were determined before and after sleep in 20 patients with OSA (apnea-hypopnea index, 48+/-7; mean+/-SEM) and eight healthy control subjects., Results: In patients with OSA, exhaled nasal and oral pentane levels after sleep were significantly higher than presleep values (6.1+/-1.2 nM vs 3.4+/-0.4 nM, and 7.0+/-1.3 nM vs 4.2+/-0.4 nM, respectively; p<0.05). Likewise, exhaled nasal and oral NO levels after sleep were significantly higher than presleep values in patients with OSA (39.7+/-3.8 ppb vs 28.4+/-2.9 ppb and 10.9+/-1.5 ppb vs 6.6+/-0.8 ppb, respectively; p<0.05). By contrast, there were no significant differences in exhaled nasal and oral pentane, and nasal NO levels before and after sleep in control subjects. Exhaled oral NO levels were significantly increased after sleep in comparison to presleep values in control subjects (p<0.05)., Conclusion: Exhaled nasal pentane and NO levels are increased after sleep in patients with moderate-severe OSA. These data suggest that upper airway inflammation is present in these patients after sleep.

Background: Exhaled pentane, a product of lipid peroxidation, has been proposed as an objective, nonspecific, and noninvasive marker of active inflammation. Reactive oxygen species, which elicit lipid peroxidation, are increased in asthma and contribute to airway dysfunction., Objective: To determine whether exhaled pentane levels are increased in acute asthma, and whether they decrease once acute asthma subsides., Methods: Expired air was collected through a mouthpiece into a pentane-impermeable collection bag from 12 patients (40+/-5 years; mean+/-SEM) presenting to the emergency department of the University of Illinois Hospital in Chicago with acute asthma. Exhaled air was also collected after discharge from the hospital once acute asthma subsided. Eleven patients with stable asthma (40+/-5 years) and 17 healthy volunteers (31+/-5 years) served as control subjects. Exhaled air and ambient room air were analyzed for pentane content by gas chromatography. Peak expiratory flow rates were determined in each subject., Results: Peak expiratory flow rates were 202+/-29 L/min during acute asthma and 327+/-26 L/min once acute asthma subsided (p<0.05). Exhaled pentane levels were 8.4+/-2.9 nmol/L during acute asthma and decreased significantly to 3.5+/-0.5 nmol/L once acute asthma subsided (p<0.05). Exhaled pentane levels were similar in patients with stable asthma and normal control subjects (3.6+/-0.4 nmol/L and 2.6+/-0.2 nmol/L, respectively; p>0.05). No pentane was detected in ambient air., Conclusion: Exhaled pentane levels are increased in patients with acute asthma and decrease significantly once acute asthma subsides.