Nasal high flow nebulization in infants and toddlers: An in vitro and in vivo scintigraphic study.

Aerosol therapy in infants and toddlers is challenging. Nebulization within a nasal high flow (NHF) circuit is attractive. The aim of this study was to quantify aerosol lung deposition when combined with NHF as compared with standard practice. Lung doses were measured scintigraphically after nebulization with jet and mesh nebulizer placed within a NHF circuit in a spontaneously breathing non-human primate model (macaque) and in the anatomical bench SAINT model, respectively representing a full-term newborn and a 9-month-old toddler. In the SAINT model, lung depositions observed with the mesh nebulizer placed in the NHF circuit set at 2 and 4 L/min were 3.3% and 4.2% of the nebulizer charge, respectively, and similar to the 1.70% observed with the control standard facemask jet nebulization (6 L/min flow). In the macaque model, the depositions observed with the mesh nebulizer in the NHF circuit set at 2 and 4 L/min were 0.49% and 0.85%, respectively, also similar to the control measurement (0.71%). Mesh nebulization within a NHF circuit set at 8 L/min and jet nebulization either within a NHF circuit or placed on top of the cannula (NHF set at 2 L/min; total flow of 8 L/min), resulted in a significantly lower lung depositions. Mesh nebulization within a NHF circuit delivering up to 4 L/min gas is likely to be at least as effective than jet nebulization with a facemask in infants and toddlers. Aerosol facemask placement on top of cannulas or jet nebulization within the NHF circuit may be less effective. Pediatr Pulmonol. 2017;52:337-344.