The Science Journal of the American Association for Respiratory Care

2010 OPEN FORUM Abstracts

AEROSOL DRUG DELIVERY IN A MODEL OF SPONTANEOUSLY BREATHING NEWBORNS USING HIGH FLOW NASAL CANNULA AT LOW AND HIGH FLOW RATES WITH HELIOX AND OXYGEN.

Arzu Ari1, Susan Roark2, Meryl Sheard1, James B. Fink1; 1Georgia State University, Atlanta, GA; 2Children Healthcare of Atlanta, Emory University, Atlanta, GA

BACKGROUND: Interest in delivery of medical aerosols with high flow nasal cannula (HFNC) has been described; however, the impact of helium-oxygen (heliox) mixture on aerosol delivery to newborns is not known. Previous models with pediatric and adult HFNC demonstrated improved aerosol delivery with lower gas flows. The objective of this study was to compare heliox and oxygen on the efficiency of aerosol delivery at low and high flow rates used with infant HFNC in a model of spontaneously breathing newborns. METHOD: An in-vitro lung model was developed using a sinusoidal pump attached through an absolute filter to a SAINT infant upper airway model in order to simulate a spontaneously breathing newborn (RR 50, Vt 8ml, and I:E ratio 1:2). A HFNC system (Fisher & Paykel) with infant nasal cannula was operated at 3 and 6 lpm using 100% oxygen and 80/20 Heliox. A vibrating mesh nebulizer (Aeroneb Solo, Aerogen Inc., Ireland) placed on the inlet (dry side) of the humidifier nebulized albuterol sulfate (1.25 mg/3mL) at each condition that was repeated three times (n=3). Drug eluted from the absolute filter distal to the model’s trachea was analyzed via spectrophotometry (276 nm). Descriptive statistics and paired-samples t test were conducted with significance at p< 0.05. RESULTS: The table below shows the mean (± SD) % of nominal dose inhaled. While drug delivery with oxygen trended to decrease with the higher flow, it was not statistically significant (p=0.280). The use of heliox at 6 lpm increased albuterol delivery by 40% compared to heliox at 3 lpm (p=0.049) and oxygen at 6 lpm (p=0.043). In contrast, at 3 lpm, heliox provided no benefit compared to oxygen. CONCLUSIONS: In this simulated model of aerosol delivery via infant HFNC, heliox improved aerosol delivery in simulated spontaneously breathing newborns only at the higher flow range studied. Further studies are needed to determine if improved albuterol delivery with heliox enhances clinical response in newborns receiving aerosol therapy via high flow nasal cannulas. Sponsored Research - None