Principles of Aerosol Therapy


Medication Nebulisers - also known as jet or small volume nebulisers (SVN) are used to turn medication into an aerosolised mist for delivery directly into the patient’s lungs.

Inhaled aerosols have considerable advantages in the treatment of many lung diseases including bronchitis and cystic fibrosis.

Nebuliser Performance - Important nebuliser performance characteristics include the aerosol particle size, drug output, nebulising time and the amount of drug delivered to the patient. The performance of a nebuliser is affected by the device construction, fill volume, flow temperature and humidity of the driving gas.

Particle Size - The area of drug deposition in the airway is determined by the particle size. Too large and the particles do not reach the lower respiratory tract, too small and they are not taken up by the alveoli and will be exhaled.

Dead Volume - The volume of medication not delivered to the patient at the completion of the nebulisation process.

Respirable Mass - The amount of aerosolised drug available to the patient based on a combination of drug output and the percentage of particles in the respirable range

Nebulising Time - The time from starting nebulisation until continuous nebulisation has ceased and depends on the flow rate, compressed air and the construction of the nebuliser. Optimal flow rates are between 6-8 l/min.