The Science Journal of the American Association for Respiratory Care

2011 OPEN FORUM Abstracts


Arzu Ari, Robert Harwood, Meryl Sheard, James Fink; Division of Respiratory Therapy, Georgia State University, Atlanta, GA

BACKGROUND: There is little information in the literature quantifying aerosol drug delivery to children via high flow nasal cannula. The objective of this study was to quantify aerosol delivery with breathing patterns of term newborns, infants and toddlers at two different drug dose volumes using a vibrating mesh nebulizer with a pediatric high flow nasal cannula (HFNC). METHODS: An in-vitro lung model consisting of a SAINT infant upper airway with collecting filter at the trachea was attached to a breathing simulator using breathing parameters of Vt 25 ml, RR 40/min for term newborns, Vt 50 ml, RR 33 /min for infants, and Vt 100 ml, RR 24/min for toddlers. The I:E ratio was set at 1:2 in all runs. A vibrating mesh nebulizer (Aeroneb Solo, Aerogen) was placed at the inspiratory inlet of a heated humidifier (Fisher& Paykel) in which the temperature was held constant at 37 degrees C while oxygen was administered via heated wire circuit to a pediatric nasal cannula at 6 lpm. Albuterol sulfate (2.5 mg) was nebulized in two dose volumes (0.5 mL and 3 mL). Drug deposited on an absolute filter distal to the model's trachea was eluted and analyzed via spectrophotometry (276 nm). One-way ANOVA and paired samples t-test were used for data analysis (p < 0.05). RESULTS: The percent (%) of nominal dose delivered to the trachea (mean +/- SD) and p values are presented in the table below. Delivered doses of albuterol ranged between 13. 8% and 17.7% with both dose volumes for the newborn and toddler. Greater deposition was observed with the 0.5 mL dose under infant parameters than with term newborn or toddler parameters (p < 0.05). Increasing tidal volumes with decreasing respiratory rates did not correlate with increased delivered doses. CONCLUSION: In this simulated model of aerosol delivery via HFNC to newborns through toddlers, deposition was similar or greater with the smaller dose volumes used with the vibrating mesh nebulizer.
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