| 摘要 |
The inner cannula (3) of a tracheostomy tube includes a shaft (30) extruded of an ePTFE material. The axial strength of the shaft is increased by heating elongate portions (34 and 35) along the shaft such as by contact with a heated roller (205). The heating is sufficient to alter the structure of the material and make the heated portions (34 and 35) more rigid than the remainder of the shaft. |
