Multiple sample needle assembly

Claim 1

A multiple sample needle assembly for determining vein entry when collecting blood samples from a patient comprising: a housing having a forward end, a rearward end and a chamber within, said housing being translucent at least around the chamber so that said chamber is viewable by a user of said assembly; a first cannula in fluid communication with said chamber extending outwardly from said forward end and adapted for insertion into a patient; a second cannula positioned in said rearward end and slidable from a first position to a second position and having a first end portion extending outwardly from said rearward end and a second end portion opposite said first end portion and extending inwardly into said chamber the end of said second end portion being blocked; an access opening in said second end portion providing flow communication between the lumen of said second cannula and said chamber; a plug of material in said rearward end of said chamber and tightly surrounding said second end portion for preventing liquid communication through said access opening when said second cannula is in said first position, but providing fluid communication between said chamber and the lumen of said second cannula through said access opening when said second cannula is in said second position inwardly displaced from said first position; resilient means inside said chamber normally biasing said second cannula in an outward direction to said first position, said resilient means adapted to contract when said second cannula slides inwardly under an applied force to said second position, said resilient means adapted to urge said second cannula outwardly, when said applied force is removed, to said first position and said plug of material being air pervious and liquid impervious.