NEW YORK (Reuters Health) - Monitoring the acidity of the breath could help doctors estimate the degree of air passage inflammation in the lungs--a key contributor to asthma, Greek scientists report.
Asthma is marked by inflammation in the airways, which leads to symptoms including wheezing, breathlessness and coughing that can range from mild to severe. Asthma attacks are often triggered by an allergic response to an environmental irritant such as tobacco smoke, mold, pollen or cockroach allergen. The disease is becoming more common worldwide, particularly among US children living in urban areas.
In the study, Dr. Konstantinos Kostikas and colleagues from the Athens Army General Hospital measured the acidity of the breath of 40 people with asthma, 20 with bronchiectasis (a relatively rare illness in which airways become enlarged), 20 with chronic obstructive pulmonary disease (COPD) and 10 healthy people. The researchers tested the breath after it had been cooled to liquid form, or condensed.
As expected, the condensed breath of patients with bronchiectasis and COPD was more acidic than that of asthmatics and healthy people. This acidity is indicative of the chronic inflammation that these patients experience with their illness, the authors note.
However, the investigation also revealed that the pH of the asthmatics' breath was more acidic in patients with moderate asthma compared to those with a mild form of the disease, according to the report in the American Journal of Respiratory and Critical Care Medicine.
Specifically, the investigators found that asthmatics' breath was much more acidic during asthma attacks, but normalized after anti-inflammatory medication was given and the asthma attack abated.
These findings suggest that measuring the pH of the breath may one day offer an inexpensive way to gauge airway inflammation in asthmatics and others with an inflammatory airway disease, Kostikas and colleagues conclude.
"For about 10 years or so, we have realized that inflammation plays a very important role in asthma," Dr. Alfred Munzer of Washington Adventist Hospital in Takoma Park, Maryland, a spokesperson for and former president of the American Lung Association, told Reuters Health in an interview. Munzer did not participate in the study.
"We used to think that spasms of the airway are what defined asthma, but there is more and more evidence that says, initially there is inflammation, and the inflammation in turn leads to the release of substances which cause constriction of the air passages," he explained.
Measuring the pH of the breath might eventually be a way to measure the degree of inflammation in the air passages, which could indicate whether or not people are likely to have severe asthma attacks, Munzer added.
SOURCE: American Journal of Respiratory and Critical Care Medicine