Use of High-Flow Nasal Cannula to Deliver Continuous Albuterol vs Large Volume Nebulizer in a Pediatric Model

Abstract

Background: Continuous albuterol delivered via large volume jet nebulizer (LVN) and aerosol mask is standard of care for status asthmaticus patients in our institution. Efficient aerosol delivery is dependent on properly fitting masks, which is difficult to maintain in children requiring continuous treatment. Recently, there has been interest in using high flow nasal cannula (HFNC) as an interface to deliver aerosol in children, but aerosol deposition data via this route is still evolving. The aim of this study was to compare continuous albuterol delivery between LVN with aerosol mask and vibrating mesh nebulizer (VMN) with HFNC in a simulated pediatric model. Methods: A lung model using a pediatric training manikin (TruCorp) with an anatomically correct airway of 6-year-old, was connected to a breathing simulator (ASL 5000, Ingmar Medical) via a collecting filter at the level of the carina simulating a spontaneously breathing child weighing approximately 20-25 kg (V_T 150 mL, RR 28, I:E 1:2.5, Peak Insp Flow 23.8 L/min). 15 mg/h of albuterol was aerosolized for 3 hours per device. LVN setup: Per manufactures guidelines, a Flo-Mist (Smith’s Medical) LVN was filled with 9 mLs of albuterol (5 mg/mL) and diluted with 66 mL of normal saline for an output of 25 mL/h at 13 L/min and connected to a snug fitting dragon mask via 180-cm of large bore corrugated tubing. Output was verified prior to testing. HFNC setup: VMN (Aerogen Solo, Aerogen) was placed on dry side of humidifier (Fisher & Paykel 850) set at 37 C and connected to an infusion pump set to deliver 7.5 mL/h of albuterol (2 mg/mL) normal saline solution. Aerosol was delivered through adult breathing circuit (RT280) and Optiflow small adult cannula (OPT942) at 3 L/min, all by Fisher & Paykel. Circuit, nasal cannula size and flow were chosen based on previous bench study. Continuous nebulization was paused hourly to replace collection filters (n = 3). Drug was eluted from filters and assayed via spectrophotometry (276 nm). Dependent T-test used for statistical analysis. Results: The mean inhaled percentage of nominal dose delivered per hour was significantly greater with VMN and HFNC circuit (14.8% ± 0.7%) versus (3.17% ± 0.6%) with LVN and dragon mask (P < .001). Conclusions: In this simulated pediatric model, administration of continuous albuterol via VMN and HFNC lead to greater than 4-fold increase in albuterol delivery compared to LVN with aerosol mask.