Date of Award

Fall 12-15-2010

Degree Type


Degree Name

Master of Science (MS)


Respiratory Therapy

First Advisor

Arzu Ari, Ph.D., RRT, CPFT, PT

Second Advisor

Robert Harwood, MSA, RRT

Third Advisor

Lynda T. Goodfellow, Ed.D. RRT, FAARC


Background: The delivery of an aerosol via a tracheostomy tube has been previously described with both a tracheostomy collar and a T-piece, but not with a Wright mask, or aerosol mask. The primary purpose of this study was to quantify lung doses using different interfaces: tracheostomy collar, Wright mask, and aerosol mask. The secondary purposes were to compare albuterol delivery between an opened vs. a closed fenestration hole and also to determine the effect of inspiratory time:expiratory time (I:E) ratio on aerosol delivery.

Methods: A teaching mannequin (Medical Plastic Labs, Gatesville, TX) with a tracheostomy opening was used. Two of the mannequin's bronchi were connected to a "Y" adaptor, which was attached to a collecting filter (Respirgard ™ II 303, Vital Signs, Englewood, CO), which was connected to a breathing simulator (Harvard Apparatus Dual Phase Control Respirator Pump, Holliston, MA) through a corrugated tube. Settings for spontaneous breathing were respiratory rate 20/min, and tidal volume 400 mL. The I:E ratios were adjusted in the first and second comparisons at 2:1 and 1:2, respectively. The nebulizer was operated by a flow meter (Timemeter, St. Louis, MO) at 8 L/min with 100% oxygen. In every condition, the flow was discontinued at the end of nebulization. The nebulizer was attached to the tracheostomy collar (AirLife™, Cardinal Health, McGaw Park, IL) in the first group, the Wright mask (Wright Solutions LLC, Marathon, FL) in the second group, and the aerosol mask (AirLife™, Cardinal Health, McGaw, IL) in the third group. Drug was eluted from the filter and analyzed by spectrophotometry (276 nm).

Data Analysis: Paired t-test, one-way analysis of variance (ANOVA), repeated measures ANOVA, post-hoc and pairwise comparisons were performed at the significance level of .05, using PASW version 18.0.

Results: Aerosol delivery was greater with the tracheostomy collar than the Wright mask and aerosol mask (p < .05). Closing the fenestration hole increased aerosol deposition significantly at 2:1 ratio (p = .04) compared to opening the fenestration at 1:2 ratio. I:E ratio and aerosol delivery were directly related. Increasing I:E ratio from 1:2 to 2:1 improved aerosol delivery significantly with tracheostomy collar-fenestration opened (p = .009), Wright mask (p = .02) and aerosol mask (p = .01).

Conclusion: This study indicates that the use of a tracheostomy collar is the best method of delivering aerosol therapy among the three interfaces. The I:E ratio of 2:1 caused greater aerosol deposition than 1:2 ratio. The aerosol deposition was better when the fenestration hole was closed compared with opened fenestration.