Aerosol Delivery to the Lung is More Efficient Using an Extension with A Standard Jet Nebulizer Than an Open-Vent Jet Nebulizer

Background: Open-vent jet nebulizers are frequently used to promote drug deposition in the lung, but their clinical efficacy and indications are not clear. Our study compared lung deposition of amikacin using two different configurations of a jet nebulizer (Sidestream (R)): one vented (N-1) and one unvented with a corrugated piece of tubing (N-2).Methods: In vitro nebulizer performance was assessed by laser diffraction and filtering. Lung delivery was evaluated by scintigraphy in baboons as a child model, and by amikacin urinary drug concentration in seven healthy spontaneously breathing volunteers. Subjects were randomly assigned to the two nebulizer systems (N-1 and N-2).Results and conclusions: In vitro results showed a higher efficiency of N-2 than N-1 in terms of lung deposition prediction (95 +/- 3mg vs. 70 +/- 0 mg; p < 0.0001). Radioactivity deposition in the baboons' lungs was lower with N-1 than with N-2 (1.8% vs. 4.7% of nebulizer charge; p < 0.05). The total daily amount of amikacin urinary excretion was lower with N-1 than with N-2 (29.5mg vs. 40.1 mg; p < 0.01). Conversely, in vivo drug output rate was higher with N-1 than with N-2 (3.1 mg/min vs. 2.2 mg/min; p < 0.05). Using a corrugated piece of tubing with standard jet nebulizers delivers higher doses to the lungs than open-vent jet nebulizers. The open-vent jet nebulizer might be recommended for rapid administration of a lower dose to the lungs and the standard jet nebulizer with corrugated piece of tubing for a higher dose in the lungs.