Background: Nebulization through high-flow nasal cannula (HFNC) has been widely used for administering aerosolized medication across various age groups. We aimed to evaluate aerosol delivery efficiency of a new HFNC device (Inspired O2) in manikins that simulated spontaneously breathing adults, toddlers, and neonates. Methods: Albuterol sulfate (2.5mg/3 mL) was administered using a vibrating mesh nebulizer (VMN) and delivered through two HFNC devices (Inspired O2 and Airvo 2). For the Inspired O2 device, two types of circuits (rubber and plastic circuits) were used in adult manikins. VMN was placed at the humidifier inlet for Inspired O2 and the humidifier outlet for Airvo 2. Aerosol delivery was evaluated at two flow settings: a low flow (0.5 times the manikin’s peak inspiratory flow) and a high flow (1.5 times the peak inspiratory flow), corresponding to 15 L/min and 45 L/min for adult, 5 L/min and 15 L/min for toddler, and 2 L/min and 6 L/min for neonate. Spontaneous breathing parameters for manikins were set as follows: adults (tidal volume VT 470 mL, frequency 21 breaths/min, inspiratory time TI 1.1 s), toddlers (VT 100 mL, frequency 20 breaths/min, TI 0.9 s), and neonates (VT 30 mL, frequency = 30 breaths/min, TI = 0.6 s). Conventional nebulization was also assessed using an aerosol mask with a jet nebulizer (8 L/min) and VMN (2 L/min) for comparison. The drug collected between the trachea and model lung was assayed using UV spectrophotometry (276 nm). Results: During aerosol delivery via HFNC, the inhaled dose was higher with low flow compared to high flow across all manikins (all P < .05) (Figure 1 and Figure 2). In-line placement of VMN with HFNC at low flows generated a higher inhaled dose than conventional nebulization with a mask (all P < .05), except for the VMN with mask in neonate manikin (7.99 ± 0.61 vs 8.47 ± 0.64%, P = .41). Regardless of flows, the inhaled dose of Inspired O2 with a plastic circuit was higher than with a rubber circuit in adults (P < .05), with the inhaled dose with Airvo2 falling between those of the two Inspired O2 circuits. In toddler and neonate models, the inhaled dose with Inspired O2 was higher than Airvo 2 at low flow (all P < .05) and lower than (4.65 ± 0.34% vs. 5.11 ± 0.31%, P = .048) or no significant difference with Airvo 2 at high flow (4.17 ± 0.31% vs. 4.36 ± 0.3%, P = .29). Conclusions: In-line nebulization using the Inspired O2 device was as effective as Airvo 2. Both HFNC devices with low flows generated higher aerosol delivery than conventional aerosol delivery through an aerosol mask.Figure1. Aerosol delivery via high-flow nasal cannula in adult manikin.Figure2. Aerosol delivery via high-flow nasal cannula in toddler and neonate manikin.
Gong et al. (Tue,) studied this question.