[Benefits of nebulized therapy: basic concepts]

Abstract

The main advantage of nebulized drugs is that they are deposited directly into the respiratory tract and thus higher drug concentrations can be achieved in the bronchial tree and pulmonary bed with fewer adverse effects than when the systemic route is used. The effectiveness of nebulization depends on many factors, including the characteristics of the drug to be nebulized (particle size, form, density, and surface tension), the anatomy of the airways, the patient's inhalation technique and the nebulization system employed, among others. The factors determining the particle size produced by a nebulizer include both the characteristics of the solution and the flow velocity of the nebulization system. The higher the flow velocity, the smaller the aerosol particles. The parameter most widely used to measure aerosolized particle size is the mass median aerodynamic diameter. Particles of between 1 and 5 μm are those with the greatest probability of reaching the site of infection in the bronchial tree and of achieving the desired therapeutic effect. Nebulization systems or apparatus are composed of a nebulization chamber where the liquid to be nebulized is introduced and aerosol and an energy source required to make the nebulizer work are generated. There are three types of nebulization systems: ultrasonic, jet and mesh nebulizers. Of the three, the most effective are mesh nebulizers. These nebulizers are also the most compact, quietest and most rapid, which translates into better patient compliance.