Factors Determining Continuous Infusion Aerosol Delivery During Mechanical Ventilation

Area of Science:

• Respiratory Medicine
• Medical Device Engineering
• Pharmacology

Background:

• Continuous nebulization of medications like albuterol and prostacyclins is a common off-label treatment for severe hypoxemic respiratory failure and asthma during mechanical ventilation.
• Vibrating mesh nebulizers are widely used, but a new breath-enhanced jet nebulizer presents a potential alternative for aerosol delivery.

Purpose of the Study:

• To compare the aerosol delivery efficiency of vibrating mesh nebulizers and breath-enhanced jet nebulizers under various mechanical ventilation conditions.
• To identify key factors influencing continuous infusion aerosol delivery from different nebulizer technologies.

Main Methods:

• An in vitro bench model simulating adult mechanical ventilation was used to test radiolabeled saline aerosol delivery.
• Six infusion pump flow rates and four breathing patterns (duty cycles) were evaluated with both vibrating mesh and breath-enhanced jet nebulizers.
• Inhaled aerosol mass was quantified, and radioactivity deposition in the ventilation circuit was measured.

Main Results:

• Aerosol delivery was primarily influenced by infusion pump flow and ventilator duty cycle (R²=0.92), not the nebulizer technology itself.
• Breath-enhanced jet nebulizers demonstrated greater reliability, with vibrating mesh nebulizers failing to nebulize completely in 20% of trials.
• Vibrating mesh nebulizers showed significantly higher deposition in the humidifier (15.3%) compared to breath-enhanced jet nebulizers (0.2%).

Conclusions:

• Both nebulizer technologies achieved comparable aerosol delivery, which was dependent on infusion pump flow and ventilator settings.
• The breath-enhanced jet nebulizer exhibited superior reliability compared to the vibrating mesh nebulizer.
• A maximum infusion flow of 10-12 mL/h is recommended for continuous nebulization with both device types.