in excess of the capacity of the cannula 10 an inner wall of the collar 130 according to this embodiment of the invention includes teeth 138 configured to prevent the collar 130 from disengaging the core 102 specifically the teeth 138 extend through an elongated slot not shown extending through the side wall of the core 102 the slot not shown extends parallel to the axis 108 and is closed at the first and second ends 104 106 the teeth 138 are slidable along the length of the slot not shown the first end 104 of the core 102 includes a luer connection 140 permanently attached thereto with a luer channel 142 open to the channel 110 of the core 102 and to a channel 16 of a cannula 10 attached thereto in an operative configuration as would be understood by those skilled in the art the luer connection 140 may be formed in a desired shape and size to permit attachment thereof to a desired device e g the ebus device the luer connection 140 may comprise a male luer or female luer connector having any of a barb threading locking ring etc to conform to the requirements of a particular device to be attached thereto as those skilled in the art will understand in accordance with an exemplary method according to the invention the collar 130 is initially positioned away from the arms 118 toward the first end 104.