Measuring the level of exhaled NO (eNO) in the breath is a new method to monitor airway inflammation in asthma and may have a role in the management of asthma. The hypotheses were that eNO will reflect the degree of inflammation in chronic asthma, and will indicate how anti- inflammatory therapy should be altered to improve asthma control. Three studies were performed to test the hypotheses. A cross sectional study was performed to define the normal range of eNO and to compare this range with those who have asthma or atopy. The second study was observational, to compare the level of eNO during and after an exacerbation of asthma. The third study was an interventional study to evaluate eNO in management of paediatric asthma. In this latter study the level of eNO was measured to monitor airway inflammation in asthmatic children with the intention of adjusting antiinflammatory drugs (inhaled glucocorticosteroids) according to the level of eNO. These studies have shown that the mean level of eNO was significantly higher in asthmatic compared with normal subjects, but not significantly different when compared with atopic non-asthmatic subjects. eNO was correlated with the number of positive skin prick tests in atopic subjects whether asthmatic or nonasthmatic. The eNO level was increased during acute exacerbations of asthma and decreased after two weeks with therapy of GCS. In a pilot study eNO appeared to be superior to FEV1 in adjusting the dose of iGCS to control asthmatic children, but this needs to be confirmed with a larger sample size. Another non-invasive method to detect inflammatory markers is the technique of exhaled breath condensate (EBC). Although NO is degraded to NOx, it was found that eNO had no significant correlation with EBC NOx but had a significant correlation with pH. Hypertonic saline challenge, an artificial model of an asthmatic exacerbation was associated with an increase in EBC volume and the release of histamine, implicating mast cell activation. These novel findings suggest that non-invasive markers can be used both for clinical and mechanistic proposes.
| Identifer | oai:union.ndltd.org:ADTP/187148 |
| Date | January 2006 |
| Creators | Ratnawati, Ratnawati, Prince of Wale Hospital Clinical School, UNSW |
| Publisher | Awarded by:University of New South Wales. Prince of Wale Hospital Clinical School |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | Copyright Ratnawati Ratnawati, http://unsworks.unsw.edu.au/copyright |
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