Exhaled biomarkers in acute asthma.

Peel, Adam (2021) Exhaled biomarkers in acute asthma. Doctoral thesis, University of East Anglia.

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Objectives – The research aimed to a) determine the feasibility of conducting a study of exhaled breath biomarkers in the acute asthma setting; and b) determine whether a positive bronchial challenge test results in detectable changes in exhaled volatile organic compounds (VOC).

Methods – The Exhaled Breath Biomarkers in Acute Asthma feasibility study was undertaken to compare two different approaches to capturing acute asthma data. In the first, participants attending secondary care for treatment of an acute asthma attack were recruited; in the second participants who were at high risk of experiencing an attack were recruited and asked to contact the researcher should such an event occur. The Bronchial Challenge Testing in Asthma study was undertaken to determine the effect of mannitol dry powder inhalation on VOC in exhaled breath.

In addition to the above studies, systematic reviews of the literature on 8-isoprostane in exhaled breath condensate and exhaled breath VOC in adult asthma were conducted.

Findings – The literature reviews found insufficient evidence to confirm that EBC 8-isoprostane levels were raised in the presence of asthma or acute asthma attack; a number of exhaled VOC were found to be associated with asthma but with a high level of inter-study variation.

Breath capture studies in acute asthma proved feasible - both approaches were successful in recruiting participants and capturing breath samples, and the acceptability of breath sampling devices was similar to that of existing clinical devices. Obtaining breath samples before systemic corticosteroids were administered and identifying infectious triggers of exacerbation proved difficult. The effect of bronchial challenge on exhaled VOC was detectable but further development of methods is required to produce reliable results.

Conclusion – Designing a phase II biomarker study with the aim of validating previous studies and estimating the accuracy of predictive models appears feasible but further methodological refinement is required.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Medicine and Health Sciences > Norwich Medical School
Depositing User: Chris White
Date Deposited: 07 Jun 2021 13:41
Last Modified: 07 Jun 2021 13:41
URI: https://ueaeprints.uea.ac.uk/id/eprint/80211

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