| 摘要 |
In a hypodermic needle having an end that attaches to a syringe, an elongated hollow shaft for passing fluid terminated at a sharpened point; the improvement comprising an electrically insulating layer positioned on the shaft and at least one electrically conductive area positioned on the insulating layer. The electrically conductive area being adapted to be connected to an electrical source. A method of determining when a hypodermic needle penetrates into tissue, vein, or lumen by providing an electrical source; connecting the electrical source electrically to a hypodermic needle designed to provide two electrically conducting portions, spaced apart from each other, and near a point on the hypodermic needle. Providing an electrical current sensing mechanism in an operating relationship to the electrical current provided by the electrical source, whereby the electrical current sensing mechanism detects the variation in the electrical current between the conducting portions to enable the identification of the change of the electrical current between an electrically conductive environment and a different electrically conductive environment. A system for determining when a hypodermic needle penetrates into tissue, vein, or lumen. The system comprises a hypodermic needle having two electrically conducting portions, spaced apart from each other, and near a point on the hypodermic needle, and electrically insulated from each other. The conducting portions being adapted to be connected to an electrical source to enable electrical current to flow through the conducting portions. The system has an electrical source electrically connected to the conducting portions. The system has a mechanism for determining the change in the electrical current between the conducting portions when the hypodermic needle is penetrating a body and a signaling device for generating a signal indicating when the conducting portions have penetrated the body and reached a predetermined position.
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