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 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.


CONCLUSIONS
Exhaled pentane levels are increased in patients with acute asthma and decrease significantly once acute asthma subsides.
Olopade
C O
CO
Department of Medicine, University of Illinois at Chicago, 60612-7323, USA.
Zakkar
M
M
Swedler
W I
WI
Rubinstein
I
I
D000208:Acute Disease; D000328:Adult; D000368:Aged; D001249:Asthma / Q000378:metabolism* / Q000503:physiopathology; D015415:Biomarkers / Q000032:analysis*; D001944:Breath Tests; D005260:Female; D006801:Humans; D008297:Male; D010366:Peak Expiratory Flow Rate; D010420:Pentanes / Q000378:metabolism*
D015415:Biomarkers; D010420:Pentanes