EXHALED PENTANE LEVELS IN ACUTE ASTHMA

Background: Exhaled pentane, a product of lipid peroxidation, has been proposed as an objective, nonspecific, and noninvasive marker of acti ve inflammation, Reactive oxygen species, which elicit lipid peroxidat ion, are increased in asthma and contribute to airway dysfunction, Obj ective: To determine whether exhaled pentane levels are increased in a cute asthma, and whether they decrease once acute asthma subsides. Met hods: Expired air was collected through a mouthpiece into a pentane-im permeable collection bag from 12 patients (40 +/- 5 years; mean +/- SE M) presenting to the emergency department of the University of Illinoi s Hospital in Chicago with acute asthma, Exhaled air was also collecte d after discharge from the hospital once acute asthma subsided, Eleven patients with stable asthma (40 +/- 5 years) and 17 healthy volunteer s (31 +/- 5 years) served as control subjects, Exhaled air and ambient room air were analyzed for pentane content by gas chromatography. Pea k expiratory flow rates were determined in each subject. Results: Peak expiratory flow rates were 202 +/- 29 L/min during acute asthma and 3 27 +/- 26 L/min once acute asthma subsided (p<0.05). Exhaled pentane l evels were 8.4 +/- 2.9 nmol/L during acute asthma and decreased signif icantly to 3.5 +/- 0.5 nmol/L once acute asthma subsided (p<0,05), Exh aled pentane levels were similar in patients with stable asthma and no rmal control subjects (3.6 +/- 0.4 nmol/L and 2.6 +/- 0.2 nmol/L, resp ectively; p>0.05). No pentane was detected in ambient air. Conclusion: Exhaled pentane levels are increased in patients with acute asthma an d decrease significantly once acute asthma subsides.