Improved prediction of asthma exacerbations by measuring distal airway inflammation

Extract

The function of the distal airway generations has in the past been difficult to assess, and in particular spirometry is insensitive to small airway disease. Novel physiological tools such as the Forced Oscillation Technique (FOT) and multiple breath washout (MBW) have demonstrated that distal disease makes an important contribution to asthma severity. Distal obstruction may result from many different factors, including remodelling, inflammation, airway instability due to loss of alveolar tethering attachments and mucus plugging. Distal airway disease is known to independently contribute to the severity of airway hyper-responsiveness in asthma [1] but unsurprisingly there is a poor correlation between distal inflammation measured directly and physiological parameters [2–4]. Distal inflammation can be studied directly using transbronchial biopsy and has been implicated in the severity of asthma [5], but this invasive technique is not suitable for routine monitoring and especially not in children.