Inhalation therapy in asthma: Nebulizer or pressurized metered-dose inhaler with holding chamber? In vivo comparison of lung deposition in children

Objective: To compare lung deposition from a nebulizer and a pressurized me tered-dose inhaler (pMDI)/holding chamber to determine their efficiency in aerosol delivery to children. Study design: Children with stable asthma (n = 17) aged 2 to 9 years inhale d in random order radiolabeled salbutamol from a nebulizer and a pMDI throu gh a nonstatic holding chamber. Body and lung deposition of radiolabeled sa lbutamol was assessed with a gamma camera. Results: Mean (absolute dose) total lung deposition expressed as a percenta ge of the nebulized dose was 5.4% (108 mu g) in younger children (<4 years) and 11.1% (222 mu g) in older children (>4 years). Mean (absolute dose) to tal lung deposition expressed as a percentage of the metered dose was 5.4% (21.6 mu g) in younger and 9.60%, (38.4 mu g) in older children. Conclusions: For the same age groups we have shown equivalent percentages o f total lung deposition of radiolabeled salbutamol aerosolized by either a nebulizer or a pMDI/holding chamber. However, the delivery rate per minute and the total dose of salbutamol deposited were significantly higher for th e nebulizer.