| 摘要 |
First and second hollow needles extend from opposing sides of a common hub which is formed in one piece of transparent material. Proximal ends of the respective needles are in communication with each other by a narrow passageway through the hub. The projecting portion of the second needle is covered by an elastomeric sheath. The hub preferably includes a magnifying formation overlying the passageway portion between the proximal ends of the needles. In use, once the point of the first needle penetrates a vein, the patient's blood pressure is sufficient to displace air from the entire first needle and at least part of the passageway through the hub. The sheath over the second needle is sufficiently elastic to allow this and expand accordingly. The blood flows into the piercing needle and the passageway between the needles, thus being viewable through the surrounding transparent material and the magnifying portion, if present. |
