The Science Journal of the American Association for Respiratory Care

2012 OPEN FORUM Abstracts

THE EFFECT OF SOURCE GAS FLOW ON TREATMENT TIMES FOR SMALL VOLUME NEBULIZERS.

John M. Bennett, Edward Hoisington, Robert L. Chatburn; Respiratory Institute, Cleveland Clinic, Cleveland, OH

BACKGROUND There are many different designs of small volume nebulizers (SVN) and they all perform differently. One performance metric in particular, treatment time, is a function of both residual volume and source gas flow. Manufacturers recommend source gas flows of between 4 and 10 L/m. Therefore, the workload associated with aerosol treatments is dependent on both the brand of nebulizer and how it is used. The purpose of this study was to compare the treatment times of two SVNs used at our institution as a function of source gas flow. We hypothesized a difference in minimum treatment times between nebulizers. METHODS We evaluated the VixOne (Westmed) and the NebuTech (Salter Labs) nebulizers charged with 3 mL of normal saline. Three nebulizers of each brand were tested in duplicate. Source oxygen flow was varied from 4-10 L/min for the VixOne and 4-8 L/min for the NebuTech (per manufacturer’s recommendations). Treatment time was defined as the time to sputter (first break in the plume of aerosol). Output aerosol was calculated as the change in mass of the nebulizer during the treatment time (assuming 1 g = 1 mL). Mean values were compared with 2-way ANOVA or t-test, with P < 0.05 indicating significance. RESULTS Raw data are shown in the graphs. Treatment time decreased as flow increased up to 6 L/min for the NebuTech and up to 9 L/min for the VixOne. The NebuTech had shorter treatment times than the VixOne (P = 0.002) across all flows. However, the NebuTech had a lower total output (1.4 mL vs 1.6 mL, P < 0.001). The shortest treatment times were not different (3.8 ± 1.3 s for NebuTech vs 3.0 ± 0.3 s for VixOne, P = 0.169). CONCLUSIONS Because treatment times were similar for the NebuTech at 6 L/min and the VixOne at 9 L/min, aerosol workload may be minimized using either nebulizer if source flow is standardized. Although the VixOne had a higher nebulizer efficiency (1.6/3.0 = 0.53) than the NebuTech (1.4/3.0 = 0.47), the NebuTech has a built in conserver reservoir. Therefore, further research is required to determine delivery efficiencies by measuring inhaled aerosol (Respir Care 2007;52(8):1037-1050). Sponsored Research - None