Cold Air Challenge of Airway Hyperreactivity in Children: Practical Application and Theoretical Aspects

Comparing methods for assessing bronchial responsiveness in children: single step cold air challenge, multiple step cold air challenge, and histamine provocation

“…Some paediatric groups have standardized a relatively simple SSCACh [1][2][3][4][5], whilst other authors have advocated a more complex multiple step approach [6]. The present study, as the first directly comparative evaluation of these two techniques, demonstrates that there is little reason for going through a time-consuming MSCACh protocol.…”

“…This 24 h interval was felt to be long enough to avoid refractoriness, and short enough to minimize spontaneous intraindividual variation of bronchial responsiveness; short-term reproducibility of CACh-responses is high [3]. Before the first challenge, a brief history was obtained and a clinical examination was performed; patients presenting with a recent history and/or the symptoms of an acute respiratory infection or an allergen exposure were not accepted for testing but received a later (minimum interval 6 weeks) reappointment.…”

“…SSCACh was performed according to an established protocol [3,5]. Cold, dry air was produced by a commercially available heat exchanger (RHES, Jaeger, Wuerzburg, Germany).…”

“…Several comparisons between pharmacological challenges and a SSCACh, however, have produced contradictory results. One group found close correlations [13], whilst others observed only weak ones or none at all [3,14,15]. A recent comparison between responses to a SSCACh and those to a histamine provocation in 123 paediatric asthma patients resulted in a correlation that was statistically significant, but showed a wide scatter of the data points around the regression line [16].…”

“…Several paediatric groups have advocated a single step approach, i.e. single step cold air challenge (SSCACh); after applying one dose of cold dry air hyperventilation, the subject's response is quantified in terms of lung function changes effected [1][2][3][4][5]. Other authors have developed a multiple step approach with progressively increasing levels of cold dry air hyperventilation, i.e.…”