The Effect of Different Interfaces on the Aerosol Delivery with Vibrating Mesh Nebulizer During Noninvasive Positive Pressure Ventilation

Abstract

Background: The effect of different interfaces on the aerosol delivery with vibrating mesh nebulizer during noninvasive positive pressure ventilation (NIV) is not clear. Materials and Methods: Noninvasive ventilator and four interfaces were connected to IngMar ASL 5000 lung simulator. Meanwhile, the vibrating mesh nebulizer was connected to a ventilator circuit to simulate the nebulization during noninvasive ventilation. The nebulizer position was placed at proximal position (near the mask) and distal position (15 cm away from the mask); the inspiratory positive airway pressure (IPAP) and the expiratory positive airway pressure (EPAP) were set to 16/4, 16/8, 20/4, and 20/8 cmH₂O, respectively. The aerosol was collected through a disposable filter placed between the simulated lung and the mask, after which the aerosol delivery was calculated. Meanwhile, we recorded the inspiratory tidal volume and the mean inspiratory flow. Results: The aerosol delivery varied between 1.7% ± 0.0% and 21.1% ± 1.1%. Only when EPAP was set to 4 cmH₂O, the statistical difference in aerosol delivery was observed between the two types of interface, and between different leak port locations (p < 0.01; p = 0.04, respectively). When IPAP/EPAP was set to 16/4 and 20/4 cmH₂O, respectively, at different nebulizer positions, there was a statistical difference between the interface with the same type but different leak port locations and between the interface with same leak port location but different inner volumes (all p < 0.01). Also, there was a correlation between the aerosol delivery and interface volume (p < 0.01, R² = 0.55; p < 0.01, R² = 0.51, respectively), and between aerosol delivery and the intentional leak of interfaces (p < 0.01, R² = 0.59; p < 0.01, R² = 0.48, respectively). When EPAP was set to 4 and 8 cmH₂O, respectively, the aerosol delivery of nebulizer distal position was significantly higher than that of proximal position (12.2% ± 5.0% vs. 9.1% ± 4.1%, p < 0.05; 2.5% ± 0. 5% vs. 2.1% ± 0.3%, p < 0.01, respectively). Conclusion: Interfaces have a significant effect on aerosol delivery during NIV. The interfaces with different inner volumes, intentional leak, and leak port location may all have an effect on aerosol delivery. The addition of a 15 cm tube between the nebulizer and the mask significantly increases the aerosol delivery.

Keywords: NIV; aerosol delivery; interface; vibrating mesh nebulizer.