Tracheal cannulas

Silver:

Silver tracheal cannulas have a high material strength and can therefore be made with very thin walls. This ensures a high rate of airflow. Silver cannulas can be very easily sterilised and remodelled/repaired, which is particularly important when they are used in clinics.

Plastic:

Plastic tracheal cannulas have a low weight. If it is a thermosensitive tracheal cannula, such as Servoplast, it is considerably more flexible than a silver cannula. Because of its temperature sensitive characteristics, it adapts better to the anatomy of the trachea. Consequently it is preferred by many patients who have to permanently wear a cannula. Since the cannula has an assortment of inner cannulas, it also provides an alternative to the silver cannula in the time immediately after surgery if the patient has an increased build-up of secretion.
The silicone tracheal cannula is another soft plastic version. They are very comfortable to wear, but are always designed without inner cannulas.

Sealing:
Sealable tracheal cannulas have an inflatable balloon (cuff) at the lower end. This seals the trachea all around. The sealing prevents the air escaping through the upper air passages (important within the framework of a respiratory therapy) and the penetration of fluids, for instance into the lower air passages.

In deciding between a plastic or a silver cannula, the stability of the tracheostoma, the sensitivity of the windpipe and also intensity of mucus formation is taken into consideration. If radiotherapy is carried out, the patient definitely requires a completely metal-free accessory device: a plastic cannula, the accompanying Velcro straps for the cannula or plastic hooks and the tracheal compresses with non-aluminised back. This avoids any radiation damage through reflections on metal.

Because of the possible danger of injury in the event of an accident, a tracheal cannula made of soft plastic should be worn when driving.
Irrespective of the material with its different characteristics, it is always worthwhile having at least two cannulas available, and one of these should always be ready for exchanging. To avoid pressure sores and chafes in the trachea, the cannulas should be of different lengths.