In Vitro Comparison of Different Nebulizers Delivering 7% Hypertonic Saline

Nebulized 7% hypertonic saline is used to treat patients with cystic fibrosis. Clinical trials supporting its use were conducted with breath-enhanced nebulizers (BEN). It is not uncommon for the specific nebulizer used in studies or prescribed by a physician to be unavailable to patients. The investigator compared the aerosol characteristics of hypertonic saline delivered by nebulizers of different operating principles.

A continuous-output nebulizer (CON), a breath-actuated (BAN) jet nebulizer, and 2 brands of BEN (Pari LC Plus and Sidestream Plus) were tested. Airway delivery and aerosol characteristics of nebulizers loaded with 7% hypertonic saline were determined with 3 breathing simulations (ie, infant, child, and adult breathing patterns) and cascade impaction, respectively. Solutes were analyzed with freezing point osmometry.

Aerosols generated with the BEN and BAN had similar mass median aerodynamic diameters (3.43-3.67 µm), geometric standard deviations (2.12-2.34), percentage of particles < 5 µm (63.1-68.9%), and percentage of particles 1-3 µm (35.9-37%). The CON produced a larger aerosol than BEN and BAN. The 2 BENs had similar airway delivery values that were greater than those for both CON and BAN.

Hypertonic saline aerosols generated with the BEN and BAN devices were similar, while that generated with the CON was different. Airway delivery was similar between the BEN devices, but higher than that observed with the BAN and CON devices.