| 摘要 |
An improved guidewire placement device for inserting guidewires into blood vessels avoiding over-penetration or needle tip disengagement from penetrated blood vessels. Also, a device that can be universally used with any type of guidewire. The guidewire, essentially a wire helically wound in spires around at least one solid core wire, has a segment specially adapted for air sealing having a cylindrical even surface, and being interiorly sealed to passage of air. The device comprises a housing and a hollow needle connected to the housing. The housing has a guidewire chamber containing a tract of the guidewire, with its tip aligned with the needle tip, gripping means for releasably engaging the guidewire and means for self-propelled advancement of the gripping means to advance the guidewire at the proper time. The housing has also a vacuum chamber communicating with the hollow needle, and vacuum creating means to create a vacuum pressure upon insertion of the needle into the patient's body tissue. The self-propelled advancement of the guidewire is actuated either automatically as a result of change of the vacuum pressure occurring within the device upon blood vessel penetration of the needle tip, as in the fully automatic embodiments, or is manually actuated by the operator upon visualization of accelerated backflow of blood, as in the semi-automatic embodiments. Upon entry of the guidewire into the blood vessel the gripping means disengages from the guidewire to allow further advancement of the guidewire and extraction of the housing from the guidewire.
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