PLETHYSMOGRAPHIC SPECIFIC AIRWAY RESISTANCE

Kirkby, J., Stanojevic, S., Welsh, L., Lum, S., Badier, M., Beardsmore, C., Custovic, A., Nielson, K., Paton, J., Tomalak, W., Stocks, J. 2010. Specific Airway Resistance in Children: The Asthma UK Initiative. European Respiratory Journal. 36: 622-629

RATIONALE:

Plethysmographic Specific Airway Resistance (sRaw) is a feasible and useful research method for discriminating lung disease in young children.  However, its use as an outcome measure in clinical management has been limited by the lack of consensus with regards to equipment, methodology and reference data. 

OBJECTIVES

1. To collate reference data from healthy children (<11y),
2. To document methodological differences and explore the impact of these differences, and
3. To ascertain if reference equations could be constructed.

METHODS:

Centres were approached to contribute sRaw data as part of the Asthma UK initiative.  A random selection of pressure-flow plots were assessed for quality and site visits elucidated data collection and analysis protocols.

RESULTS:

Five centres contributed 2,872 sRaw measurements. There were significant inter-centre differences (p<0.0001) between sRaw measurements.  Marked differences in methodology and analysis precluded pooling of these retrospective data to create reference ranges. However, a list of recommendations (PDF, 86 KB) and a sRaw over-read sheethas been developed to facilitate standardised data collection and analysis.

CONCLUSIONS:

Due to methodological differences, normative sRaw data collected from a single centre may be misleading. Given the potential clinical usefulness of sRaw, methodological guidelines must be established, and prospective data collection from healthy children is required to develop appropriate reference equations.