| 摘要 |
<p>A tracheostomy tube assembly comprises an outer tube 1 and an inner cannula 2. The machine end fitting 10 of the outer tube 1 has a bore 105 of circular section interrupted by two flats 106 and 107. The machine end fitting 20 of the inner cannula 2 has an external surface 204 shaped to fit within the fitting 10 on the outer tube 1 and also has two flats 207 and 208 aligned with the flats 106 and 107 on the outer tube fitting. Tubes of different sizes or other characteristics have flats with different orientations such that only inner cannulae suited for a particular outer tube can be inserted in the correct tube.</p> |
