Aerodynamic performance of jet nebulizers marketed in Germany

Background: Aerosol characteristics play a major role for successful inhalation therapy. We tested 13 recent jet nebulizers, which are currently marketed in Germany, under standardized in vitro conditions. Four jet nebulizers are especially designed for pediatric use. Methods: Sodium fluoride solution was aerosolized and measured according to Euro norm EN 13544–1:2007 + A1 (Aug. 2009). The measurements were performed using a sinus pump breathing simulator (adult breathing pattern) as well as a next generation cascade impactor (NGI). The following parameters were analyzed: Total aerosol output (AO), aerosol output rate (AOR), mass median aerodynamic diameter (MMAD) with geometric standard deviation (GSD), fine particle fraction (FPF <5 µm and <3 µm), total respirable delivered dose <5 µm (RDD<5 µm), and respirable dose delivery rate <5 µm (RDDR<5 µm). Results: The AO and AOR varied between 1.9 to 6.6 mg NaF and 0.4 to 1.7 mg NaF/ min, respectively. The MMAD ranged from 2.1 µm to 6.8 µm, and the FPF <5 µm (FPF <3 µm) varied between 33.1% (18.4%) and 86.8% (67.2%). GSD spread from 2 to 2.5 µm. RDD<5 µm and RDDR<5 µm were calculated and varied substantially between 0.61 to 5.28 mg NaF and 0.26 to 1.18 mg NaF/min, respectively. Conclusion: The aerosol performance of 13 tested nebulizers, characterized by the quantity and quality of generated aerosols, showed significant differences. Being aware of such results, caregivers can choose an appropriate nebulizer for an individual patient.