Abstract
The low tidal volume and flow in preschool children may reduce the efficiency of aerosol delivery from a pressurized metered-dose inhaler (pMDI) through a traditional holding chamber. A prototype small-volume steel holding chamber with two one-way valves was devised to prolong aerosol availability in the chamber and to ensure unidirectional airflow. Dead space between the valves was minimized to less than 2 ml. The dose-delivery and rate of passive disappearance of a budesonide pMDI aerosol were compared between this prototype and the large-volume, single-valved plastic Nebuhaler, in 164 asthmatic children less than 8 yrs of age. In vitro, the half life of aerosol disappearance in the steel prototype and the plastic Nebuhaler was > 30 s and 9 s, respectively. In vivo, the prototype delivered an age-independent mean dose of 38% of the nominal dose, and the Nebuhaler delivered an age-dependent mean dose, ranging from 42% of the nominal dose in children > or = 4 yrs to 19% of the nominal dose in infants. We conclude that the use of plastic for holding chambers may influence dose-delivery, and single-valve control may cause age-dependent dose-delivery. Reproducible age-independent drug-delivery may be achieved by pMDI aerosol inhaled through a small-volume metal holding chamber with separate inlet and outlet valves and minimized dead space. This holding chamber would improve the possibilities of aerosol therapy for young children.
Original language | English |
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Journal | European Respiratory Journal |
Volume | 8 |
Issue number | 5 |
Pages (from-to) | 856-60 |
Number of pages | 5 |
ISSN | 0903-1936 |
Publication status | Published - May 1995 |
Keywords
- Administration, Inhalation
- Aerosols
- Asthma
- Bronchodilator Agents
- Budesonide
- Child
- Child, Preschool
- Cross-Over Studies
- Equipment Design
- Female
- Humans
- Infant
- Male
- Nebulizers and Vaporizers
- Pregnenediones
- Single-Blind Method
- Steel