Aerosolized medications are often required in mechanically ventilated infants to resolve complex respiratory issues. Current practice utilizes hand ventilation, via an anesthesia bag, to deliver nebulized medications. However, there is little evidence to ensure optimal delivery of medications.
Using a simulated pediatric lung model (ASL 5000), with a Mapleson anesthesia breathing circuit, we delivered 2.5 mg albuterol sulfate to a viral/bacterial filter (Respiguard 202). We compared four configurations with varied fresh gas flows (FGF) and nebulizer placements. Five Registered Respiratory Therapists (RRT) delivered the aerosol into the collection filter targeting the defined ventilation parameters. Each configuration was tested in random order by each RRT to avoid fatigue bias. After albuterol delivery, eluded albuterol sulfate concentration was determined by spectrophotometry.
We measured no inter-user variability. We measured significant differences in the efficacy of albuterol delivery between each configuration (One Way ANOVA, Tukey?s post hoc, N=5). The configuration with the nebulizer closest to the airway was most effective, as we recovered 22.6±1.8% of albuterol. The standard clinical model was least effective, as only 0.6±0.9% of albuterol was recovered. Configurations 2 and 3, in which the FGF was reduced, and the nebulizer was moved proximal to the FGF also increased albuterol, with 4.2±1.5% and 14.0±1.7% recovery, respectively.
Significant efficiency of nebulized drug delivery using an anesthesia breathing circuit can be achieved using alternate configurations. Our data suggests that current clinical approaches are inefficient but could be markedly improved with relatively simple changes.