In Vivo Deposition of High-Flow Nasal Aerosols Using Breath-Enhanced Nebulization

Area of Science:

• Respiratory Medicine
• Medical Device Technology
• Pharmacokinetics

Background:

• Conventional nebulizers have limitations in aerosol delivery under high-flow conditions.
• High-flow nasal cannula (HFNC) therapy requires optimized aerosol delivery systems.
• Existing devices offer unpredictable aerosol output with fixed maximal rates.

Purpose of the Study:

• To measure regulated aerosol delivery to the lungs using a novel nebulizer with HFNC.
• To assess the efficacy of the i-AIRE nebulizer in delivering aerosol under high airflow.
• To determine if aerosol delivery can be reliably controlled and titrated at the bedside.

Main Methods:

• Nine healthy volunteers received humidified air at 60 L/min via HFNC.
• A breath-enhanced jet nebulizer (i-AIRE) was used in series with the HFNC system.
• Radio-labeled saline (99mTc DTPA) was infused at controlled rates (12, 20, 50 mL/h) and lung deposition was measured using a gamma camera.

Main Results:

• Aerosol deposition rates in the lungs (µg NaCl/min) showed a strong correlation with infusion rates.
• Deposition rates were 7.84 ± 3.2 at 12 mL/h, 43.0 ± 12 at 20 mL/h, and 136 ± 45 at 50 mL/h.
• Deposition efficiency ranged from 0.44–1.82%, with peripheral deposition and no dependence on breathing frequency.

Conclusions:

• Breath-enhanced nebulization via HFNC reliably delivers aerosol to the lungs at high nasal airflows.
• The rate of aerosol delivery is simply controlled by regulating the infusion rate.
• This technology enables bedside titration of lung deposition for critically ill patients.