Abstract
Introduction: Children with asthma often have normal spirometry despite significant disease. There is evidence that the small airways are affected which may be reflected in Multiple Breath Washout (MBW) and the Lung Clearance Index (LCI). There are only few studies using MBW in children with asthma. Existing data regarding bronchodilator effect are contradictory. The aim of the present pilot study was to compare LCI in asthma and controls and assess the effect of salbutamol in children with asthma on the LCI.
Methods: Unselected patients with a diagnosis of asthma visiting the out patient department of our hospital between 04-2010 and 03-2011 and healthy controls were included. MBW was performed as inert gas MBW using sulfurhexafluorid (SF6) as the tracer gas. Clinical data were documented and spirometry and MBW (EasyOne Pro, ndd Switzerland) were performed before and after the use of salbutamol (200 - 400 ug). Healthy controls performed baseline MBW only.
Results: 32 children diagnosed with asthma (4.7-17.4 years) and 42 controls (5.3-20.8) were included in the analysis. 2/32 failed spirometry. LCI differed between patients and controls, with mean LCI (SD) of 6.48 (0.48) and 6.21 (0.38) respectively (P=0.011). Use of salbutamol had no significant effect on LCI for the groupt. 4/30 patients had a positive bronchodilator test in spirometry. In these, LCI showed a significant difference pre- and post- bronchodilator, with mean (SD) of 7.04 (0.6) and 6.56 (0.72) respectively (P= 0.029).
Conclusion: These pilot data show that asthma patients and controls both have a LCI in the normal range. However in patients the LCI is significantly higher indicating that MBW may have a role in assessing small airways disease in asthma.
- © 2013 ERS