Distribution of aerosol particles generated by an ultrasonic nebulizer under various conditions

Abstract

Distribution of RI aerosol particle generated by an ultrasonic nebulizer (OMRON, NEU 11 B) in the respiratory and digestive tracts is studied. The aerosol of 99 m-Tc-diethylene triamine penta acetic acid (DTPA) was inhaled through the mouth during quiet respiration in five healthy volunteers. Each volunteer inhaled the aerosol under several conditions, as follows ; 1) aerosol generated by the ultrasonic nebulizer as a control, 2) aerosol with compressed air flow (3 L/ min), 3) aerosol with vibration (100 Hz), 4) aerosol of 99 m-Tc-human serum albumin in order to change the size of particles. The deposition rates to the mouth, pharyngolaryngeal region, lungs and stomach were compared among these conditions. Under the control study, more than 90% of total deposited aerosol in the body was counted in the bilateral lungs and about 4% was counted in the pharyngolaryngeal region. Only in the trial using the aerosol with vibration, the deposited rate to the pharyngolaryngeal region increased to 1.2 to 5.4 times larger than the rate of control study. Under the other trials, the deposition pattern of RI aerosol was almost similar to that of the control study. These results suggested that the deposition rate to the pharyngolaryngeal region was extremely low under the usual laryngeal nebulizer therapy. To make the therapy more effective, some manoeuvre including vibration to increase the deposition rate to the pharyngolaryngeal region should be developed. © 1995, Society of Oto-rhino-laryngology Tokyo. All rights reserved.