The Science Journal of the American Association for Respiratory Care

1999 OPEN FORUM Abstracts


Dean Hess, PhD, RRT, FAARC,* Jolyon P. Mitchell, PhD,+ Dominic Coppolo, RRT,+ Mark W. Nagel,+ Allan D. Archer,+ Rick Blacker.+ *Massachusetts General Hospital and Harvard Medical School, Boston MA; +Trudell Medical International, London ON.

Background: Nebulizer design is known to affect performance. In this study, we compared fine particle mass from nebulizers of four designs.

Methods: We tested traditional disposable nebulizers (Baxter Misty-NebTM, Hudson Updraft-II Neb-U-MistÒ), breath-enhanced nebulizers (Pari-LC-DTM), nebulizers with collection bags (Westmed CirculaireTM), and a Trudell AeroEclipseTM (with breath actuation disabled). Five of each device with three replicates (n = 15) were tested using an in-vitro model of spontaneous breathing. A rigid bar was placed between the two compartments of a test lung (Michigan Instruments TTL). The drive lung was attached to a ventilator (Infrasonics Infant StarÒ) to simulate spontaneous breathing (tidal volume 0.6 L, rate 10/min, TI 2 s). A bacterial/viral filter (Trudell MT3000) was placed between the nebulizer and slave lung. Flow was monitored between the test lung and filter (Novametrix VentcheckÒ). Albuterol solution (0.625 mg/mL) was placed into the nebulizers (4 mL), which were powered with air (8 L/min). Filters were replaced at one minute intervals (flow to the nebulizer was discontinued during filter replacement) until sputtering occurred. The filter was washed with methanol (20 mL) and albuterol concentration was measured with HPLC-UV spectrophotometry. Particle size was measured using a Malvern Mastersizer. Fine particle mass was calculated as the product of mass % <4.7 mm and total nebulizer output.

Results: Fine particle mass from the AeroEclipseTM nebulizer was greater than that from the other nebulizers (P<0.001) (see figure).

Conclusions: Fine particle mass was affected by nebulizer design. The clinical relevance of this finding awaits further investigation. Further evaluation of the breath-actuated feature of the AeroEclipseTM is warranted.

(See Original for Figure)


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