In vitro comparison of heliox and oxygen in aerosol delivery using pediatric high flow nasal cannula

Abstract

Drug administration via high flow nasal cannula (HFNC) has been described in pediatrics but the amount of albuterol delivery with an HFNC is not known. The purpose of this study is to quantify aerosol delivery with heliox and oxygen (O(2)) in a model of pediatric ventilation. A vibrating mesh nebulizer (Aeroneb Solo, Aerogen) was placed on the inspiratory inlet of a heated humidifier and heated wire circuit attached to a pediatric nasal cannula (Optiflow, Fisher & Paykel). Breathing parameters were tidal volume (V(t)) 100 ml, respiratory rate (RR) 20/min, and I-time of 1 sec. Albuterol sulfate (2.5 mg/3 ml) was administered through a pediatric HFNC with O(2) (100%) and heliox (80/20% mixture). A total of 12 runs, using O(2) and heliox were conducted at 3 and 6 L/min (n = 3). Drug was collected on an absolute filter, eluted and measured using spectrophotometry. The percent inhaled dose (mean ± SD) was similar with heliox and O(2) at 3 L/min (11.41 ± 1.54 and 10.65 ± 0.51, respectively; P = 0.465). However at 6 L/min drug deposition was ≥ 2-fold greater with heliox (5.42 ± 0.54) than O(2) (1.95 ± 0.50; P = 0.01). Using a pediatric model of HFNC, reducing delivered flow from 6 to 3 L/min increased inhaled albuterol delivery ≥ 2-fold but eliminated the increase in inhaled drug efficiency associated with heliox.

In Vitro Evaluation of Aerosols Delivered via the Nasal Route

“…We speculate that the differences between both studies could be related to the fact that they used bias flow (3 L/min), did not release the expiration in the system, and used a non-anatomically correct model. Ari et al 25 compared aerosol delivery through a heated flow nasal cannula using a vibrating mesh nebulizer with bias flows of 3 and 6 L/min. The authors used a pediatric breathing pattern (V T of 100 mL, breathing frequency of 20 breaths/min, inspiratory time of 1 s), and a non-anatomically correct model allowed a straight path of the aerosol between the cannula and artificial nares.…”

“…8,22,23 Several authors have studied transnasal drug delivery with nasal cannulas using non-anatomically correct models. 24,25 Other authors evaluated drug delivery using mouthbreathing models. 11,[26][27][28] Because infants and young children are obligate nose breathers, studies utilizing the nasal route for aerosol delivery are of importance.…”

Aerosol Therapy During Noninvasive Ventilation or High-Flow Nasal Cannula

“…Ari et al 31 conducted an in vitro comparison of a helium-oxygen mixture (heliox) and oxygen in aerosol delivery using pediatric HFNC. A mesh nebulizer was placed on the inspiratory inlet of a heated humidifier, and a heated-wire circuit was attached to a pediatric nasal cannula.…”

Characterization of Ribavirin Aerosol With Small Particle Aerosol Generator and Vibrating Mesh Micropump Aerosol Technologies

“…The most recent advancement has been the vibrating mesh micropump aerosol generator that has been reported with a variety of interfaces common to acute and critical care applications (eg, mask, mouthpiece, high-flow nasal cannula, and both invasive and noninvasive mechanical ventilation). [12][13][14][15][16] The vibrating mesh micropump is commercially available and has been shown to deliver more aerosolized drug, such as salbutamol, than traditional jet nebulizers in neonatal, pediatric, and adult models. 17 The small-particle aerosol generator-2 is a large-volume pneumatic nebulizer with a large reservoir, designed for continuous nebulization.…”