Background: Nebulizers are a popular means of delivering aerosolized medication, primarily albuterol, to the bronchial airways of patients, and there has been extensive research done on numerous nebulizers used with nebulizer T-pieces and corrugated tubing. Very little research has been performed on other types of nebulizer delivery systems and there is no substantial information on how effective various nebulizer delivery systems are in terms of the quantity and particle size of aerosolized medication delivered to the patient. In this study the Circulaire and the AeroTee, two devices that rely on bags to store aerosol during patient exhalation, are evaluated and compared to the conventional nebulizer T-piece with corrugated tubing.
Methods: Three each of the nebulizer T-piece with corrugated tubing, the Circulaire, and the AeroTee were sampled using 3 Vixone nebulizers. Each one of the 3 nebulizer delivery systems used the same 3 Vixone nebulizers. Each nebulizer delivery system was evaluated by connecting a constant-flow vacuum and compressed gas source cycled to simulate patient breathing at a respiratory rate of 14 breaths/min and an inspiration-expiration ratio of 1:2. Medication delivered was determined by sampling a portion of the simulated patient's flow onto a membrane filter and calculating the total medication received by the patient. Particle size was determined by sampling with a cascade impactor under ambient conditions.
Results: The Circulaire delivered significantly less medication than the nebulizer T-piece with corrugated tubing (p < 0.001), whereas the AeroTee delivered substantially more medication than the nebulizer T-piece with corrugated tubing (p < 0.001). The particle size delivered by the Circulaire was significantly smaller than that of the nebulizer T-piece with corrugated tubing (p < 0.001), whereas the AeroTee delivered particle size equivalent to a nebulizer T-piece with corrugated tubing (p = 0.82).
Conclusion: There are clinically important differences between nebulizer delivery systems. When evaluating the optimum means for delivering aerosolized medication, equal consideration should be given to both the brand of nebulizer and the nebulizer delivery system.