Noninvasive methods to measure airway inflammation: future considerations

Abstract

This last contribution to the series focuses on open questions regarding: 1) methodological issues; and 2) the potential clinical application of the noninvasive methods such as induced sputum and the analysis of exhaled air for the assessment of airway inflammation. In addition their potential future role in occupational health and the early diagnosis of neoplastic lesions are briefly discussed. The future clinical application of noninvasive methods will depend on the progress made to improve their practicability, particularly in rendering them less time consuming and cheaper. To assess their clinical value, prospective studies are needed to establish whether patients actually benefit from the results obtained. This is also important to implement the methods into the healthcare system and to obtain adequate financial compensation. Therefore, it is necessary to know: 1) whether the assessment of airway inflam‐mation can aid in coming to an earlier and better defined diagnosis; 2) whether by repeated monitoring it is possible to avoid exacerbations through earlier interventions; and 3) whether the long‐term outcome of patients is improved through knowledge of the type and degree of airway inflammation that is taken into account in selecting the appropriate treatment. In the meantime a wealth of data has become available, both for induced sputum and the analysis of exhaled air, which give these methods the potential to be incorporated into future clinical practice. This, however, will, amongst the other issues, depend on favourable cost‐benefit ratios which should also be the subject of future prospective studies.

Dose reduction of inhaled corticosteroids under concomitant medication with montelukast in patients with asthma

“…Whether methacholine responsiveness possesses a predictive value has been a matter of debate [25], and this may apply mainly to longterm effects of steroid treatment [2]. With regard to sputum eosinophils or exhaled NO, there are no data currently at hand from large prospective studies that have used these parameters for therapeutic management and demonstrated their clinical value in addition to conventional clinical or functional measures [26].…”

Usefulness of the Exhaled Breath Temperature Plateau in Asthma Patients

“…Patients with a neutrophil count >61% were classified as having neutrophilic asthma, those with eosinophil counts >3% were classified as having eosinophilic asthma, and those with neutrophil counts ≤61% and eosinophil counts ≤3% were classified as having paucigranulocytic asthma [17,18,19]. …”

Is there more than one inflammatory phenotype in asthma?

“…Practical considerations including cost, technical expertise, and the technician time needed to process samples and count inflammatory cell populations would prohibit its use in the diagnosis and monitoring of all cases of suspected asthma. 38 However, in those subjects in whom disease control is proving difficult, sputum induction might be valuable in differentiating between patients with poorly suppressed allergic inflammation, who may be more likely to benefit from increased conventional asthma treatment, and those with non-eosinophilic inflammation who require alternative approaches.…”