Efficacy of a prototype inspiratory-synchronized small particle versus conventional vibrating mesh nebulizer during pediatric and neonatal mechanical ventilation

Background: An inspiration-synchronized vibrating mesh nebulizer (VMN) has been reported to improve aerosol delivery during adult mechanical ventilation. A prototype VMN generating smaller particles was developed. We aimed to compare the aerosol delivery efficiency of small-particle and conventional VMNs in inspiration-synchronized and continuous modes during neonatal and pediatric mechanical ventilation.

Methods: A critical care ventilator with heated humidified circuits connected to an endotracheal tube (ETT) and passive test lung was set to pediatric and neonate parameters. Albuterol (2.5 mg/ml, 1 ml) was administered using both small-particle and conventional VMNs in inspiration-synchronization and continuous modes. For the pediatric model, VMN was placed at the humidifier inlet, inspiratory limb at Y-piece, and between Y-piece and ETT (Y-ETT). For the neonatal model, VMN was placed at the humidifier inlet and between Y-ETT. Each setup was repeated five times. Albuterol collected on the filter distal to the ETT was eluted and assayed with UV spectrophotometry (276 nm).

Results: The inspiration-synchronized VMN generated higher inhaled doses compared to continuous VMN across all nebulizer placements, particle sizes, and aerosol generation models (all p < .05). The highest inhaled doses (42.2 ± 2.0% and 40.7 ± 1.0% for pediatric and neonate, respectively) were observed with the small-particle inspiration-synchronized VMN placed at Y-ETT. In the pediatric model, the inhaled dose with inspiration-synchronized conventional VMN was similar, independent of nebulizer placements (24.4 ~ 27.0%). In contrast, the inhaled dose was greatest with continuous VMN placed at the humidifier inlet. With the neonatal model, VMN placed at Y-ETT yielded higher doses than the humidifier inlet, and small-particle VMNs outperformed conventional VMNs across all settings (all p < .05).

Conclusion: The prototype small-particle VMN positioned between Y-piece and ETT in an inspiration-synchronized mode optimized aerosol delivery during mechanical ventilation in both pediatric and neonatal models.