Enhanced Aerosol Delivery During High-Flow Nasal Cannula Therapy

Area of Science:

• Respiratory medicine
• Medical device engineering
• Pharmacology

Background:

• Aerosolized drug delivery via high-flow nasal cannula (HFNC) decreases with increasing gas flow.
• Breath-enhanced jet nebulizers (BENs) may improve aerosol output compared to standard devices.

Purpose of the Study:

• To test the hypothesis that BENs increase aerosol output during HFNC.
• To compare BEN technology with vibrating mesh nebulizer (VMN) technology for aerosol delivery.

Main Methods:

• Aerosol output of BENs and VMNs was measured in an isolated circuit under simulated HFNC conditions (5-60 mL/h saline infusion).
• Drug delivery was quantified in vitro using a 3D-printed head model with HFNC (10-60 L/min) and ^99mTc/saline infusion.
• Tracheal aerosol delivery rates (µg NaCl/min) were measured using a shielded ratemeter.

Main Results:

• BEN output increased with gas flow, reaching a maximum of 50 mL/h, while VMN maximum was 12 mL/h.
• At 60 L/min HFNC, BEN delivered 3.16 to 316.8 µg NaCl/min, significantly more than VMN's 23.5 to 61.7 µg NaCl/min.
• Drug delivery rate was dependent on infusion pump flow and HFNC gas flow, but independent of nebulizer type at specific infusion rates (5-12 mL/h).

Conclusions:

• Increasing gas flow enhances BEN aerosol output, demonstrating breath-enhancement effects.
• BENs delivered up to 5 times more aerosol than VMNs at 60 L/min HFNC.
• BEN technology may enable bedside titration of aerosolized medication doses in critically ill patients by adjusting infusion rates.