title: Aerosol Delivery Using Jet Nebulizer and Vibrating Mesh Nebulizer During High Frequency Oscillatory Ventilation: An In Vitro Comparison.
abstract: BACKGROUND
  High frequency oscillatory ventilation (HFOV) is used in critically ill patients with severe hypoxemic respiratory failure. The purpose of this in vitro study was to determine the efficiency of aerosol delivery with different lung parameters during simulated neonatal, pediatric, and adult HFOV.
  
  
  METHODS
  Sensormedics 3100A/B ventilators were used to deliver infant, pediatric, and adult HFOV. Two types of aerosol generators were chosen for testing: 1) a continuous jet nebulizer (JN) with a unit-dose of 5.0 mg/2.5 mL salbutamol sulfate diluted into 4 mL, and 2) a vibrating mesh nebulizer (VMN) with salbutamol sulfate were run to completion of aerosol generation. Both aerosol devices were placed 1) between the ventilator circuit and the endotracheal tube (ETT) (proximal position); and 2) at the inlet of the heated humidifier (distal position) (n = 5). Drug was collected on a bacterial filter placed distal to the ETT, and the drug eluted and analyzed with a UV Spectrophotometer at 276 nm. T- test and ANOVA tests were used for comparison (p < 0.05).
  
  
  RESULTS
  The inhaled drug delivered by JN was 0%-0.6% of the nominal dose when placed at distal position, and 0%-3% at proximal position (p < 0.01), while the VMN was 0%-0.5% at distal and 8.6%-22.7% at proximal position (p < 0.01). Aerosol delivery during HFOV was greater with adult settings than pediatric and infant settings with VMN and JN (22.7%, 8.6%, and 17.4% respectively, p < 0.01). When the aerosol delivery device was placed at the distal position, negligible drug mass was observed (<0.5%), regardless of the nebulizer device used.
  
  
  CONCLUSIONS
  During HFOV, aerosol delivery with the nebulizer placed at proximal was greater than placement distal from the ETT, with VMN delivering more drug than JN. The inhaled drug was delivery correlated positively with ETT size, MAP, and bias flow, and inversely proportional to power settings.
authors.affiliation: 1 Department of Respiratory Therapy, Chang Gung Memorial Hospital , Chiayi, Taiwan .|6 Department of Respiratory Care, Chang Gung University of Science and Technology, Chiayi Campus, Taiwan .
authors.forename: Tien-Pei
authors.initials: TP
authors.lastname: Fang
authors.affiliation: 2 Department of Respiratory Therapy, Chang Gung University , Taoyuan, Taiwan .
authors.forename: Hui-Ling
authors.initials: HL
authors.lastname: Lin
authors.affiliation: 1 Department of Respiratory Therapy, Chang Gung Memorial Hospital , Chiayi, Taiwan .
authors.forename: Shu-Hua
authors.initials: SH
authors.lastname: Chiu
authors.affiliation: 1 Department of Respiratory Therapy, Chang Gung Memorial Hospital , Chiayi, Taiwan .
authors.forename: Szu-Hui
authors.initials: SH
authors.lastname: Wang
authors.affiliation: 3 Department of Respiratory Therapy, Seattle Children's Hospital , Seattle, Washington.
authors.forename: Robert M
authors.initials: RM
authors.lastname: DiBlasi
authors.affiliation: 4 Department of Internal Medicine, Chang Gung Memorial Hospital , Chiayi, Taiwan .
authors.forename: Ying-Huang
authors.initials: YH
authors.lastname: Tsai
authors.affiliation: 5 Division of Respiratory Therapy, Georgia State University , Atlanta, Georgia .
authors.forename: James B
authors.initials: JB
authors.lastname: Fink
keywords: aerosol delivery; breathing patterns; high frequency oscillatory ventilation; jet nebulizer; vibrating mesh nebulizer