As an inexperienced RT student, I have a question that I was wondering if anybody could answer. In my Respiratory Care Pharmacology book by Rau, it states that the lung deposition of MDI's w/ & w/o spacers, DPI & SVN ranged from 8.8% for MDI, 9.1% for DPI, 12.4% for SVN & 13% for MDI with spacer. My question is does anybody know the percent amount of lung deposition for an ultrasonic nebulizer. With a smaller particle size than a conventional SVN, I would think that it would be much more efficient @ aerosolized medication delivery. I asked my instructor & she has no idea & wants me to find out. Anybody have an idea that is backed by anything other than a SWAG?(Scientific Wild Ass Guess). Any information regarding this matter would be greatly appreciated.Thank You in Advance. --Toby.