| 摘要 |
A cannula preferably a tracheostomy tube assembly, has an outer catheter 1 and an inner cannula 2 that is removable from the outer catheter. The inner cannula 2 has two elongate regions 20 and 21 along its length of different flexibility. The main body 20 of the cannula 2 may be relatively stiff and a narrow region 21 along its length be of a more flexible material. Alternatively, the main body may be flexible and a narrow region of the wall thickness or a rib may be constructed of relatively stiffer material. Flexibility may also be provided by weakening the tube in a continuous elongate section or by means of corrugations. |
