| 摘要 |
In general, the confirmation of a puncture in a blood vessel is made through a visual check of flush back of the blood from the blood vessel into a puncture needle assembly. The conventional puncture needle assembly incorporates a membrane filter permeable to air but impermeable to blood, in order to prevent the blood from flooding outside. The conventional puncture needle, however, cannot be used suitably for the puncture of a blood vessel deep in the tissue. In the puncture needle assembly of the invention, an air relief opening is formed in a portion of a puncture needle hub, catheter hub or an end plug attachable to the puncture needle hub or the catheter, hub other than the portion which constitutes a pressing surface on which the thumb of the user is placed to exert a thrust force for puncturing the tissue and the blood vessel, as in the case of ordinary syringes. The air in the puncture needle and in the puncture needle hub is relieved through the air relief opening, thus to permit smooth flush back of the blood.
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