H. Kumazawa et al., AN INCREASE IN LARYNGEAL AEROSOL DEPOSITION BY ULTRASONIC NEBULIZER THERAPY WITH INTERMITTENT VOCALIZATION, The Laryngoscope, 107(5), 1997, pp. 671-674
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.