The Science Journal of the American Association for Respiratory Care

2010 OPEN FORUM Abstracts

AEROSOL LUNG DEPOSITION USING A VIBRATING MESH NEBULIZER DURING HIGH FREQUENCY OSCILLATORY VENTILATION IN AN ADULT LUNG MODEL OF ARDS.

Mark S. Siobal1, Arzu Ari2, Jim Fink2; 1Anesthesia, SFGH/UCSF, San Francisco, CA; 2Division of Respiratory Therapy, Georgia State University, Atlanta, GA

Background: Lung deposition of aerosolized medication during high frequency oscillatory ventilation (HFOV) in adults has not been thoroughly quantified. We measured simulated lung deposition in an adult lung model during HFOV using a vibrating mesh nebulizer (VMN). Method: A VMN (Aeroneb Solo, Aerogen) was placed between the 3100B (Viasys) ventilator “Y” and a Ballard Trach Care double swivel elbow inline suction catheter. The suction catheter was connected to a 7.5mm endotracheal tube inserted into a bifurcated trachea model and the cuff was inflated. Bacteria filters were positioned at the distal ends of each bronchial lumen and connected via a “Y” adapter to a single compartment of a test lung (TTL, Michigan) set at a compliance of 20 mL/cm H20. The ventilator was set to amplitude of 90 cm H2O, mean airway pressure of 34 cm H2O, 33% inspiratory time, with bias flow of 40 L/min. The VMN was filled with a 3 mL (2.5 mg) dose of albuterol and nebulized continuously until empty. A total of 3 runs each were performed at frequencies of 4 Hz, 8 Hz, and 12 Hz. Albuterol was eluted from the filters and analyzed with UV spectrophotmetry (276 nm) and reported as percent of total dose. Results: The percent of albuterol delivered distal to the mainstem bronchi in a bifurcated trachea model was 8.7 ± 0.78 % at 4 Hz, 15.1 ± 6.9 % at 8 Hz, and 17.5 ± 3.1 % at 12 Hz. There was a trend of increasing inhaled mass with frequency. The average deposition across all frequencies tested was 13.8%. Conclusion: During HFOV in an adult lung model of ARDS, simulated lung deposition of drug aerosolized with the VMN is consistent with the range of dose efficiency reported with conventional ventilation (Ari et al, Resp Care July 2010). During HFOV, drug delivery appears to increase with higher frequencies. Further investigation of lung deposition, penetration, and clinical response to aerosol medication delivery during HFOV in adult patients with ARDS is warranted. Sponsored Research - Jim Fink has a consulting relationship with Aeroogen