Blood collection set with retractable needle

An automatically shieldable blood collection set is provided. The blood collection set includes a needle assembly having a hub to which a needle cannula is fixedly attached. A safety shield is telescoped relative to the hub and the needle cannula such that the hub and the needle cannula can be moved from a distal position where the needle cannula is exposed to a proximal position where the needle cannula is safely shielded. A spring is provided between the shield and the hub to propel the hub and needle cannula proximally relative to the shield and into surrounding relationship with the needle cannula. A retainer is provided for releasably holding the hub and needle cannula in a distal ready-to-use condition relative to the shield. An actuator releases the retainer and enables the hub and needle cannula to be propelled by the spring. A lock may be provided for preventing inadvertent re-exposure of the needle cannula.

DETAILED DESCRIPTION A blood collection set in accordance with the subject invention is identified generally by the numeral 10 in FIGS. 1 - 3 . Blood collection set 10 includes a needle assembly 12 having a hub 14 , a needle cannula 16 , a safety cap 18 , a safety shield 20 and a spring 22 . Blood collection set 10 further includes a flexible tube 24 having a distal end 26 connected to needle assembly 12 and a proximal end 28 connected to a fitting 30 . Fitting 30 is configured to be placed in communication with a reservoir into which blood drawn by needle assembly 12 may be deposited. Flexible tube 24 and fitting 30 may be of conventional prior art construction. Hub 14 is formed from a thermoplastic material and includes a proximal end 32 , a distal end 34 and a rigid tube 36 that extends axially between the ends. Tube 36 defines a passage 38 extending axially therethrough. An annular flange 40 is mounted on proximal end 32 of hub 14 and defines an outside diameter greater than the outside diameter of rigid tube 36 of hub 14 . Hub 14 further includes an actuator 42 that projects radially outwardly from a location on hub 14 near distal end 34 . Actuator 42 defines a distal face 44 which, as explained further herein, functions as a retainer for releasably retaining shield 20 in a retracted position. Actuator 42 further includes a proximal face 46 which extends from outer surface 40 by a radial dimension that is less than the radial dimension of distal face 44 . A ramp face 48 extends angularly between distal face 44 and proximal face 46 of actuator 42 . Needle cannula 16 includes a proximal end 50 , a pointed distal end 52 and a lumen 54 extending therebetween. Proximal end 50 is mounted securely in distal end 34 of hub 14 , such that lumen 54 communicates with passage 38 through hub 14 and with flexible tube 24 . Safety cap 18 is a generally tubular structure that is unitarily molded from a rigid plastic material. Safety cap 18 has a proximal end 56 that is frictionally engaged at distal end 34 of hub 14 and a distal end 58 that extends distally beyond needle cannula 16 for preventing accidental sticks prior to use of blood collection set 10 . Safety shield 20 is a substantially cylindrical tube having a proximal end 60 and a distal end 64 . A pair of flexible wings 66 project transversely from a location on safety shield 20 near distal end 64 . As shown in FIG. 1 , wings 66 are substantially coplanar and enable needle assembly 12 to be taped to the skin of a patient in proximity to a puncture site. However, wings 66 can be folded approximately 90 ° toward one another to provide a convenient handle for gripping needle assembly 12 . Such gripping is helpful prior to use of needle assembly 12 when safety cap 18 is being removed and when needle cannula 16 is being inserted into a patient. Safety shield 20 defines an inside diameter which is less than the outside diameter of flange 40 on hub 14 . However, the inside diameter of safety shield 20 is greater than the sum of the outside diameter of tube 36 of hub 14 plus the radial dimension of distal face 44 on actuator 42 . Thus, shield 20 can be slid over actuator 42 on hub 14 . Safety shield 20 includes a proximal locking aperture 68 and a distal retaining aperture 70 each of which is dimensioned to receive actuator 42 . Safety shield 20 defines a length measured from locking aperture 68 to distal end 64 that exceeds the distance from actuator 42 to distal end 52 of needle cannula 16 . Spring 22 surrounds rigid tube 36 of hub 14 . Spring 22 has an inside diameter smaller than the outside diameter of flange 40 and an outside diameter smaller than the inside diameter of safety shield 20 . Spring 22 is in a compressed state when hub 14 is in its distal position relative to safety shield 20 , as shown in FIGS. 1 and 2 . Needle assembly 12 is used in a conventional manner by initially folding wings 66 toward one another to enable convenient digital manipulation of needle assembly 12 . Safety cap 18 then is slidably removed from needle cannula 16 , and needle cannula 16 is inserted into a patient. Wings 66 then may be folded flat against the skin of the patient and taped in place. Flexible tube 24 and fitting 30 will be used in conventional manner for connecting blood collection set 10 to a bag or other reservoir. Upon collection of a sufficient volume of blood, any tape that had held wings 66 to the skin of a patient will be removed, and needle assembly 12 then is withdrawn. To prevent accidental sticks with the contaminated needle cannula 16 , the medical an need merely squeeze actuator 42 and safety shield 20 between a thumb and forefinger. squeezing will urge the actuator 42 within the safety shield 20 , and forces of spring 22 will b 14 and needle cannula 16 proximally. Spring 22 will continue to propel hub 14 and cannula 16 in a proximal direction and into shielding relationship within safety shield 20 . After distal end 64 of safety shield 20 is distally beyond pointed distal end 52 of needle cannula 16 , actuator 42 will align with locking aperture 68 in shield 20 . The guiding of actuator 42 into locking aperture 68 can be achieved by a tapering of interior surface regions of safety shield 20 at loctions opposite locking aperture 68 . In this condition, distal face 44 of actuator 42 will engage against distal portions of locking aperture 68 to prevent the re-exposure of needle cannula 16 . Additionally, distal portions of locking aperture 68 will engage against distal face 44 of actuator 42 to prevent a complete removal of safety shield 20 from hub 14 .