RT Journal Article
SR Electronic
T1 Aerosol bolus dispersion and effective airway diameters in mildly asthmatic children
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP 566
OP 573
DO 10.1183/09031936.95.08040566
VO 8
IS 4
A1 H Schulz
A1 A Schulz
A1 P Brand
A1 T Tuch
A1 E von Mutius
A1 R Erdl
A1 D Reinhardt
A1 J Heyder
YR 1995
UL http://erj.ersjournals.com/content/8/4/566.abstract
AB The contribution of aerosol techniques, the estimation of aerosol bolus dispersion and effective airway dimensions, to the clinical diagnosis of paediatric asthma was studied. In 47 children, aged 11 +/- 2 yrs, with mild asthma (forced expiratory volume in one second (FEV1) 83 +/- 9% of forced vital capacity (FVC)) effective airway diameters were derived from the recovery of inhaled 1 micron sebacate droplets. Intrapulmonary dispersion of inhaled boluses of 0.4 micron droplets was studied, by characterizing the concentration distributions of droplets in the exhaled air by their standard deviation and skewness. Effective airway diameters increased in asthmatic subjects with increasing body size, and did not differ from those obtained in 16 healthy children of similar age and height. Standard deviation and skewness of particle boluses exhaled from shallow lung depths were higher in the asthmatic children than the healthy children (e.g. standard deviation 91 +/- 17 ml vs 79 +/- 15 ml, skewness 0.38 +/- 0.16 vs 0.23 +/- 0.16, respectively, for boluses in 140 ml lung depth). The sensitivity and specificity of bolus dispersion to detect alterations in lung function was comparable to that of FEV1/FVC, the most sensitive conventional lung function parameter in the present study. There was no correlation between body height or lung function and bolus parameters. We conclude that aerosol measurements do not provide an obvious benefit for the clinical diagnosis of mild paediatric asthma, but bolus dispersion supplies additional information on alterations in convective gas transport in the diseased lung.