The Science Journal of the American Association for Respiratory Care

2012 OPEN FORUM Abstracts


Hui-Ling Lin1, James B. Fink2; 1Respiratory Therapy Program, Chang Gung University, Taoyuan, Taiwan; 2Division of Respiratory Therapy, Georgia State University, Atlanta, GA

Background: Aerosol delivery through mechanical ventilation is influenced by aerosol generation pattern. Purpose: The purpose of this in vitro study was to compare the efficiency of three modes of pneumatic nebulization provided by a new ventilator. Method: Three modes of pneumatic nebulization: inspiratory intermittent, continuous, and expiratory intermittent were compared, using ventilator (Galileo Gold; Hamilton Medical Inc) set to deliver a tidal volume 600 mL, reparatory rate 16 b/min, inspiratory time 1.0 second, and PEEP 5 cmH2O, via endotracheal tube and collecting filter to a single test lung (TTL, Michigan Instrument Inc). A unit dose of salbutamol (5 mg/2.5 mL, GlaxoSmithKline) diluted to 4 mL with distilled water was added to a small volume nebulizer (Galemed Corp). The nebulizer was placed in the inspiratory limb of the ventilator circuit and connected to the ventilator nebulization outlet via an oxygen tube and powered by the the flow provided by the ventilator with each of the 3 modes (n = 5). Time for nebulization recorded in minutes. Drug collected in the filter, nebulizer, T-piece and tubing was eluted and analyzed with a spectrophotometer (Thermo Fisher Scientific) at wavelength 276 nm. Analysis of variance with Bonferroni test and Kruskal-Wallis test were used for statistical analysis, and p< 0.05 was used for statistical significance. Result: Table shows drug as % of total dose (mean ± SD). Drug in T-tube was greater with intermittent inspiration higher than continuous (p = 0.002) and intermittent expiration (p = 0.001). Drug deposited in the corrugated tube with intermittent inspiration was significantly higher than it with continuous (p = 0.016) and intermittent expiration (p = 0.005). Nebulization times (median and range ) intermittent inspiration continuous and intermittent expiration were 38.89 ( 34.92-42.25 ), 14.28 ( 12.22-14.55 ), and 17.65 ( 16.53-17.77 ) minutes respectively (p = 0.003). Conclusion: Aerosol delivery was similar in all modes; however the nebulization time with intermittent inspiration was >2 fold more than the other two modes. Sponsored Research - None Drug depositions among three modes (mean ± SD as % of total dose)