Agulha hipodérmica tendo um acabamento de superfície externo diferencial

摘要

A hypodermic needle (10) of the present invention includes an elongate hollow tube (12) with a proximal end (14), a distal end (16) and has a bore (18) therethrough. The proximal end (14) of the needle of the invention has a hub (20) fixedly attached thereto to connect the needle releasably to a fluid handling device with the distal end (16) having a point (24) for facilitating penetration of the needle into a patient's tissue. The outside surface (26) of the tube (12) has a proximal portion (28) with a lower coefficient of sliding friction with the patient's tissue than the coefficient of sliding friction with the patient's tissue of a distal portion (30) of the outside surface (26) of the tube (12). The higher coefficient of friction of the distal portion (30) enables a practitioner to substantially discriminate the needle's penetration of structures in the patient's tissue while the lower coefficient of friction proximal portion (28) substantially reduces drag force for passage of the proximal portion through the structures already penetrated by the distal portion (30).