Abstract: A tracheostomy tube assembly comprises an outer tracheostomy tube and an inner cannula of a flexible material preformed to the shape of the outer tube and smooth on its inside and outside. The outer tube is straight at its patient end and has a short straight machine end with a coupling. The patient and machine ends are separated by a curved intermediate region divided along its length into two sub-regions. The first sub-region closer the machine end has a small radius of curvature; the other sub-region closer to the patient end has a radius of curvature at least three times that of the first sub-region. This shape enables the patient end of the assembly to be aligned with the patient's trachea.

Abstract: A tracheal tube or other medico-surgical device has a surface coating containing lysozyme enzyme, which is effective to reduce the build-up of bacteria on the tube.