The Science Journal of the American Association for Respiratory Care

2010 OPEN FORUM Abstracts

INFLUENCE OF NASAL CANNULA, FLOW RATE AND HUMIDIFIER IN AEROSOL DRUG DELIVERY DURING HIGH FLOW NASAL OXYGEN ADMINISTRATION IN A SIMULATED NEONATAL LUNG MODEL.

Arzu Ari1, Susan Roark2, Lucrecia Lobo2, Robert Harwood1, Meryl Sheard1, James B. Fink1; 1Georgia State University, Atlanta, GA; 2Emory University, Children Healthcare of Atlanta, Atlanta, GA

BACKGROUND: With the proliferation of systems for administration of oxygen via high flow nasal cannula (HFNC), interest in delivery of medical aerosols has increased. The children’s hospital currently uses two HFNC systems and wanted to quantify aerosol delivery and influence of nasal cannula size, flow rate and humidifiers. Therefore, the purpose of this study was to compare aerosol delivery efficiency of the two HFNC systems, using a simulated model of neonatal ventilation. METHOD: An in-vitro lung model using a sinusoidal pump attached through an absolute filter to a SAINT infant upper airway model was developed to simulate spontaneously breathing newborns (RR 50, Vt 8ml, and I:E ratio 1:2). Two HFNC systems (RT 329 Continuous Flow Circuit, Fisher Paykel and Conchatherm, Hudson) were operated at 35 – 40 degree C, at oxygen flows of 3 and 6 LPM, with manufacturer’s infant and pediatric nasal cannulas. A vibrating mesh nebulizer (Aeroneb Solo, Aerogen Inc., Ireland) was placed on the inlet (dry side) of the humidifier to nebulize albuterol sulfate (2.5 mg/3mL). Drug deposited on an absolute filter distal to the model’s trachea was eluted and analyzed via spectrophotometry (276 nm). Each condition was repeated in triplicate. Descriptive statistics, paired and independent samples t-tests were conducted with significance at p< 0.05. RESULTS: Table shows deposition of inhaled dose (mean percent of nominal dose ± SD) of albuterol inhaled. With the infant cannula, there was no significant difference between the Fisher Paykel and Hudson humidifiers at 3 lpm (p=0.256) and 6 lpm (p=0.762). With the pediatric cannula, the Fisher Paykel delivered more aerosol at both flow rates than the Hudson (p=0.018 and p=0.038, respectively). Drug deposition trended higher at 3 lpm than 6 lpm, for both systems but was only significant with the Hudson (p=0.009). CONCLUSIONS: The size of nasal cannula, type of humidifier and amount of flow rate used during aerosol therapy impact aerosol delivery. Reducing flow rate and using pediatric nasal cannula with larger bore tubing/prongs increased aerosol delivery in this simulated neonatal lung model. Sponsored Research - None