Abstract
Objective: to determine what proportion of nebulized drugs is deposited through the prongs of a neonatal high flow nasal cannula circuit. Methods: Total cannula output, aerosol deposition in the tubes of the oxygen nasal cannula and the amount of compounds residue in the sidestream disposable were determined by two different and independent in vitro experiments performed in triplicate. Quantification of the compounds was performed using high-pressure liquid chromatography with high resolution mass spectrometric detection. Setting: nebulization of budesonide, ipratropium bromide and salbutamol with a jet nebulizer into a humidified and heated (37˚C) Optiflow™ nasal cannula system for 20 minutes at a flow of 6 L/min. Main outcome measures: Percentage of compounds in cannula output. Results: For all compounds, both in vitro experiments resulted in a total cannula output of less than 1%. A small amount of the compounds (i.e., 0.27 to 3.62 % of the nominal dose) could be measured in the rinsing water of the nasal cannula tubes and the highest amount (i.e., 28.43 to 53.63%) remained in the sidestream disposable nebulizer chamber. Conclusion: Routine use of nebulization in neonatal high flow nasal cannula circuits is not recommended. Further research is needed to determine if optimizing nebulizing conditions can result in a therapeutic amount of drugs delivered through an Optiflow™ nasal cannula system in order to simultaneously deliver oxygen and medication without patient manipulation.