Nebulization of a Suspension of Budesonide and a Solution of Terbutaline into a Neonatal Ventilator Circuit

Abstract

Methods

The amount of nebulized budesonide and terbutaline delivered through an endotracheal tube (ETT) was measured in vitro using a test lung and filters in a neonatal ventilator circuit. Budesonide suspension (1 mg) was used in a concentration of 0.5 mg/mL and terbutaline solution (5 mg) in a concentration of 2.5 mg/mL.

Results

The median amount of terbutaline deposited on the inspiratory filters was significantly higher than that of budesonide: 0.4% vs 0.3% of the nominal doses with the nebulizer connected 8 cm upstream of the ETT and nebulization performed in a constant output mode (setup A), and 2.8% vs 1.0% with the nebulizer connected directly to the ETT and nebulization performed in a breath-synchronized mode (setup B) (p < 0.05 for both). The corresponding amounts of drug deposited on the waste filters with setup A were 19.2% for terbutaline and 12.6% for budesonide, and with setup B 16.2% for terbutaline and 6.2% for budesonide (p < 0.05 for both).

Conclusions

The ratio between drug delivery to the inspiratory and waste filters, describing the relationship between lung deposition and wastage of drug to the ventilator circuit, was setup-dependent but not drug-dependent. The ratio with setup A was 0.02 for both budesonide and terbutaline. The respective ratios were significantly (p < 0.05) higher for budesonide (0.16) and for terbutaline (0.17) with setup B. The differences in the delivered doses of the two drugs through the ETT seems to be a function of both the drug formulation and the nebulizer-ETT setup. With the nebulizer connected directly to the ETT and nebulization in breath synchronized mode, the differences between the two drugs were enhanced, compared with the nebulizer connected upstream of the ETT and nebulization in constant output mode. The results indicate that a solution is superior to a suspension in terms of drug delivery through an ETT.