AN INCREASE IN LARYNGEAL AEROSOL DEPOSITION BY ULTRASONIC NEBULIZER THERAPY WITH INTERMITTENT VOCALIZATION

In acute or chronic laryngitis as well as pharyngitis, nebulization wi th steroid and antibiotics is considered to be a safe and effective tr eatment. However, the optimal dose, frequency, duration, and method of administration by ultrasonic nebulization is not known. To evaluate w hether there is continual improvement using ultrasonic nebulizer thera py, the deposition rate of aerosol particles into the upper airway was studied. We analyzed the deposition rate in the upper airway by a cou nting system of radioactive isotope (99mTc-diethylene triaminepentaace tic acid; 99mTc DTPA). Volunteers in good health inhaled an aerosol co ntaining 99mTc DTPA under various conditions of inhalation, Deep and s low inhalation at a respiratory rate of 12 breaths/minute resulted in a high deposition rate of 99mTc DTPA in the lung and a low deposition rate in the larynx. In contrast, faster inhalation at a respiratory ra te of 36 breaths/minute resulted in an increase in the isotope deposit ion rate in the larynx. Furthermore, when the volunteers vocalized int ermittently during the fast inhalation at a respiratory rate of 36 bre aths/minute, the isotope deposition rate in the volunteer's larynx was higher than in all other inhalation conditions. These results suggest that fast inhalation with intermittent vocalization is one of the imp ortant inhalation methods used to improve the deposition rate of aeros ol particles into the upper airway with an ultrasonic nebulizer.