Rationale: Aerosolized medications are crucial for resolving respiratory issues in mechanically ventilated patients. Infants often receive nebulized medications via hand ventilation using an anesthesia bag, but evidence on optimal aerosol delivery with this method is limited. We tested various configurations of the Mapleson breathing circuit to optimize albuterol delivery to simulated intubated pediatric patients. Methods: Using a simulated pediatric lung model (ASL 5000) with the semi-open Mapleson anesthesia circuit, we delivered 2.5 mg albuterol sulfate to a viral/bacterial filter (Respiguard 202). Four models were compared, varying fresh gas flows (FGF), nebulizer placements, and the use of dead space. Five Registered Respiratory Therapists (RRTs) administered the aerosol into the collection filter, following defined ventilation parameters. Each model was tested in random order to avoid fatigue bias. Albuterol concentrations eluted from in-line filters were measured by spectrophotometry (absorbance at 276 nm). Results: No inter-user variability was observed among the RRTs. Significant differences in albuterol delivery efficacy were noted between models (One Way ANOVA, Tukey’s post hoc, N=5). Model 4, with the nebulizer closest to the collecting filter, recovered 21.7±3.87% of albuterol. The standard clinical model was least effective, with only 0.1±0.47% albuterol recovery. Conclusion: Modifying the anesthesia breathing circuit significantly improved aerosol drug delivery efficiency. Our findings suggest that current clinical practices for nebulized drug delivery are inefficient and can be markedly improved with simple adjustments in nebulizer positioning and gas flow within the circuit.