Introduction: Aerosol delivery during mechanical ventilation may be influenced by respiratory mechanics and ventilator mode. This study evaluated their impact on albuterol delivery using an inspiration-synchronized vibrating mesh nebulizer (sync VMN) versus a continuous VMN in simulated adult models. Methods: Three adult lung models simulating normal, COPD, and ARDS (Compliance: 60, 80, 20 mL/cmH2O, Resistance: 5, 20, 5 cmH2O/L/s) were connected to an 8.0mm endotracheal tube and a ventilator. The sync VMN was positioned at the Y-piece and synchronized to the first 50% of inspiration, while the continuous VMN was placed at the humidifier inlet. Each model had exhaled humidity incorporated and was ventilated under volume control (VC) and pressure-regulated volume control (PRVC) modes with settings of tidal volume (Vt) 420 mL, RR 16, I:E 1:2, PEEP 8 cmH2O, and pressure support (PS), adjusted to achieve the same Vt. Albuterol (2.5 mg/3 mL) was delivered and collected via a filter placed distal to the ETT. Drug was quantified by UV spectrophotometry at 276 nm. Results: Across all modes and models, the sync VMN delivered higher inhaled doses than the cont VMN (p=.008), except in ARDS during PS (27.3±2.1 vs 24.3±2.6% p=.095). The highest inhaled dose was achieved in ARDS model during VC with sync VMN (48.6±2.3%). Within the sync VMN group, VC delivered the highest inhaled dose across all models, followed by PS and PRVC. Mode-related differences were significant in both ARDS and COPD (adjusted p<.05), but not in the normal model. Across models, sync VMN in VC resulted in higher dose in ARDS compared to COPD and normal models (both p=.008), whereas ARDS had the lowest delivery in PRVC and PS modes (adjusted p<.05). The continuous VMN showed lower but more constant aerosol delivery, with minimal mode-related differences in normal and COPD models, and significant variation only in ARDS (p=.005). Conclusions: The sync VMN delivered higher but more variable aerosol delivery than the continuous VMN. Optimal delivery occurred during VC ventilation using sync VMN, particularly in the ARDS model.
Albuainain et al. (Sun,) studied this question.