We evaluated the effects of medication-diluent volume, gas flowrate, and nebulizer model on the duration of nebulization and the percentage of medication solution delivered from eight nebulizers. METHOD: The mass of each nebulizer was determined when it was empty and again after it had been charged with 0.3 mL of metaproterenol and saline diluent of 2, 3, 4, or 5 mL. Oxygen powered the nebulizer at flowrates of 6 and 8 L/min. Five trials were run at each flowrate-diluent combination, with a new nebulizer used for each trial. Nebulization was considered complete when visible or audible evidence of nebulization had ceased. Mass was determined after each trial, and the amount of solution nebulized was calculated. RESULTS: The amount of medication solution nebulized increased significantly with greater diluent volume and with greater flowrate (p < 0.001 in each case). The duration of nebulization significantly decreased with smaller diluent volume and with increased flowrate (p < 0.001 in each case). The amount of solution nebulized and the duration of nebulization differed significantly among nebulizer models (p < 0.001 in each case). CONCLUSIONS: Nebulizer function is affected by diluent volume, flowrate, and nebulizer model. Greater diluent volumes increase the amount of delivered medication solution, but with longer nebulization times.
Hess et al. (Tue,) studied this question.