Ultrasonic surfactant nebulization with different exciting frequencies

Intratracheal bolus instillation of natural lung surfactant is the treatmen t of choice in neonatal respiratory distress syndrome and an increasing par t in adults' therapy. For reasons of hemodynamics, surfactant distribution and efficiency the application mode should be improved. Nebulization seems to have some advantages but its technical realization is difficult. The aim of the present study was to investigate if ultrasonic nebulization with ex citing frequencies higher than 2.8 MHz can improve the efficiency of surfac tant nebulization without changing the surface-active properties of the mat erial. Exciting frequencies of 1.7, 3.3 and 4.0 MHz were used to produce a surfactant aerosol. The phospholipid content in the liquefied aerosol and p article size distinctly dropped with higher frequencies. The surface activi ty was not altered in the produced aerosol and neither in the surfactant re maining in the nebulizer. Although possible, ultrasonic nebulization of sur factant suspensions is ineffective because of a striking decrease in phosph olipid content. (C) 2000 Elsevier Science B.V. All rights reserved.