Barium Enema

Medication Nebulisers also referred to as small volume or jet nebulisers (SVN) are devices used to turn medication into an aerosolised mist to deliver directly into the patient's lungs. Inhaled aerosols have considerable advantages in the treatment of many lung diseases including bronchitis and cystic fibrosis. The required dose is much smaller compared to that taken systemically and the side effects are therefore negligible. The onset of the action is quicker, and the drug itself is more selective.

Nebuliser Performance. Important characteristics of nebuliser performance include the aerosol particle size generated, drug output, nebulising time and the amount of drug delivered to the patient. device construction, fill volume, flow temperature, humidity of the driving gas are factors affecting the performance of a nebuliser.

Particle Size is an important characteristic of nebuliser performance. Large particles do not reach the lower respiratory tract depositing themselves in the mouth, upper airways and gastrict tract. Particles too small will not be taken up by the alveoli and are exhaled. Respirable particles taking part in lung deposition has been accepted to range from 0.5 microns to 5.0 microns in diameter size.

Nebulising Time is the time from starting nebulisation until continuous nebulisation has ceased and depends on the flow rate, compressed air and the construction of the nebuliser. These are a major influence on aerosol size distribution. Optimal flow rates recommended are between 6-8 litres per minute, with 8l/min providing a smaller particle size and shorter nebuliser time, the time it takes for the volume to completely nebulise. A SVN should deliver at least 80% of the solution within 15 minutes.

Reconcentration is a SVN is greater at a diluent volume of 2ml than one of 4 ml and for that reason it is suggested 4ml maybe superior than 2ml as a diluent formula.

Dead Volume is the volume of medication not delivered to the patent during nebulisation and exists as the volume left in the nebuliser at the end of nebulisation.

Respirable Mass is the combination of aerosolised drug output and the percentage of particles in the respirable range. This is the amount of aerosolised drug available to the patient on inspiration.