Abstract
BACKGROUND: Aerosol delivery via high-flow nasal cannula (HFNC) has gained popularity due to the increased use of the modality for treating hypoxemic and hypercapnic respiratory failure. Various HFNC devices are available in the United States; however, the effectiveness of aerosol delivery via HFNC devices remains unclear. Thus, this study aimed to investigate the impact of various commercially available devices on transnasal aerosol delivery. METHODS: This was a bench study that used a 2-chamber lung model, in which one chamber was connected to an adult manikin with anatomically correct upper-airway proportions. The other chamber was connected to a critical care ventilator used to simulate spontaneous breathing. A size large nasal cannula was placed at the nasal opening of the manikin. Five different HFNC devices (Hamilton-C1, OptiFlow, Airvo2, V60 Plus, and Vapotherm) were compared. Four flow settings were used on each device, with a vibrating mesh nebulizer placed at the humidifier. Salbutamol (2.5 mg/3 mL) was used during the experiments to quantify inhaled drug doses. A collection filter was placed between the manikin's trachea and the lung model. The drug was eluted from the filter and assayed with ultraviolet spectrophotometry (276 nm). RESULTS: Among the 5 HFNC devices, OptiFlow had the highest inhaled dose at 10 L/min (mean ± SD 18.2% ± 1.2%). At 20 L/min, the Hamilton-C1 (mean ± SD 13.5% ± 0.4%) performed marginally better than the OptiFlow (mean ± SD 12.6% ± 1.9%) and Airvo2 (mean ± SD 12.8% ± 1%). At high flow settings (40-60 L/min), the inhaled dose of Hamilton-C1 was 2-3 times that of the Airvo2 and V60 Plus. When compared with the other devices, the mean inhaled dose with the Vapotherm was lower (0.9-2.5%). In all devices, the inhaled dose decreased as the flow increased. CONCLUSIONS: Transnasal aerosol delivery was significantly impacted by the types of HFNC devices and flow settings. Nominal doses might need to be adjusted if changing HFNC devices or flow is not an option.