title: 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.
authors.affiliation: Department of Allergic Diseases, Helsinki University Hospital, Meilahdentie 2, FIN-00250 Helsinki, Finland. Markku.turpeinen@hus.fi
authors.forename: M
authors.initials: M
authors.lastname: Turpeinen
authors.forename: K
authors.initials: K
authors.lastname: Nikander
mesh_terms: D000336:Aerosols; D001993:Bronchodilator Agents / Q000008:administration & dosage*; D019819:Budesonide / Q000008:administration & dosage*; D006801:Humans; D007231:Infant, Newborn; D007235:Infant, Premature, Diseases / Q000188:drug therapy; D007442:Intubation, Intratracheal; D008171:Lung Diseases / Q000188:drug therapy; D008961:Models, Structural; D009330:Nebulizers and Vaporizers; D012996:Solutions; D013535:Suspensions; D013726:Terbutaline / Q000008:administration & dosage*; D012122:Ventilators, Mechanical
chemical_list: D000336:Aerosols; D001993:Bronchodilator Agents; D012996:Solutions; D013535:Suspensions; D019819:Budesonide; D013726:Terbutaline