INTRODUCTIONThe AMSA® manosonic nebulizer uses acoustic vibration and a flow of air to create an aerosol from a solution or suspension of a drug. The aerosol created this way is claimed to have enhanced penetration and drug delivery. It is administered under short-term overpressure, meaning that the aerosol is able to penetrate into the middle ear through the Eustachian tube (ET).PURPOSEof the study: The aim of this study is to identify the active substances used in AMSA® manosonic nebulization for treating common ENT diseases in children aged 2-17 years and to evaluate the overall effectiveness of AMSA® manosonic nebulization in this context. Assessments were done by comparing conditions before and after nebulization using the following tests: (1) Eustachian tube function test, (2) tympanometry, and (3) otoscopy.MATERIAL AND METHODSThis study was a retrospective study with ethics committee consent. 129 children, comprising 56 girls and 73 boys. They were aged between 2 and 17 years, with a mean age of 6.9 years (SD = 3.0). There were 74 children up to 6 years and 55 children over 6 years of age. Children had the following conditions: (1) chronic otitis media with effusion, OME (n = 86), (2) Eustachian tube dysfunction, ETD (n = 34) (3) Other conditions (e.g. cholesteatoma, retraction pocket), (n = 9). Combination of medicines administered in this study was: Budesonide + ambroxol (with or without NaCl), Budesonide (with or without NaCl), Budesonide + N-acetylcysteine (with or without NaCl), Budesonide + hyaluronic acid, Budesonide + ambroxol (with hyaluronic acid), Ambroxol (with or without NaCl).RESULTSThe number of nebulizations ordered was between 1 and 20 treatments, but most commonly, pa-tients were given a nebulization series of 10 treatments. This was the case for 80.6 % of the patients. Most patients with OME and ETD had 10 treatments ordered (79 % and 79.5 %, respectively), while all patients with other conditions had 10 treatments. Analysis of the tympanometry results was done in terms of the number of affected ears (not by individual). There were 210 ears with complete tympanometry (both pre and post), including 142 ears with OME, 54 with ETD, and 14 others. Statistically significant changes (improvements) after AMSA nebulizations were found for statistic compliance and middle ear pressure. Otoscopy assessments were done in all ears. The results were abnormal in 155 ears (73.8 %) and normal in 55 ears (26.2 %). After AMSA nebulizations, the number of abnormal results decreased to 117 ears (55.7 %) and normal results were found in 93 ears (44.7 %).CONCLUSIONUse of the AMSA manosonic nebulizer appears to be an effective way of improving chronic medical conditions in children - such as chronic otitis media with effusion and Eustachian tube defect - but only if patient compliance can be achieved. The most frequently used active substance was budesonide, irrespective of whether additional secretolic/mucolytic agent was administered.