Pulmonary deposition of aerosols in children with cystic fibrosis.

The efficiency of delivery of an aerosol to 22 children with cystic 
fibrosis, aged 8 months to 17 years, was investigated with the 
use a standard ultrasonic nebulizer. The study was designed to simulate 
clinical conditions as closely as possible. Retention of the aerosol was 
monitored with a scintillation camera interfaced to a small digital computer. 
The children also had ventilation studies with xenon-133, which allowed comparison 
of the distribution of aerosol with regional ventilation. The aerosol was 
visualized within the lungs of all 22 patients. Between 0.8 and 
6.5 per cent of the initial activity was deposited in the 
lungs, representing an average of 0.27 ml. per therapy session or 
0.0131 ml. per kilogram of body weight. There was a positive 
correlation (r = 0.89; p < 0.01) between increasing age and 
greater pulmonary deposition of the aerosol. There was decreased aerosol entry 
to regions which were poorly ventilated. The efficiency of aerosol deposition 
is variable in children with cystic fibrosis, depending primarily on the 
age of the patient, whereas its distribution within their lungs is 
related to regional variations in the severity of the pulmonary disease. 
