Medical device with needle safety shielding

In one aspect, a medical device is provided which includes flexible tubing having a distal end and a proximal end and at least a first lumen extending from said distal end to said proximal end; a first needle cannula having proximal and distal ends, said first needle cannula being mounted at said distal end of said tubing and in fluid communication with said lumen; a second needle cannula mounted at said proximal end of said tubing and in fluid communication with said lumen; a shield disposed over said tubing, said shield extending substantially the entire length of said flexible tubing, and said shield being movable relative to said first needle cannula from an initial proximal position wherein said first needle cannula is exposed to a distal position wherein said distal end of said first needle cannula is covered by said shield; and an actuator for actuating the shield at a location spaced from the first needle cannula, preferably closer to the second needle cannula than to the first needle cannula.

FIELD OF THE INVENTION

This invention relates to needle safety shielding for preventing inadvertent needle contact and, more particularly, to needle safety shielding for medical devices, such as blood collection sets, infusion sets, or fluid administration sets.

DESCRIPTION OF THE PRIOR ART

Blood collection sets are known in the prior art, wherein an Intravenous (IV) needle cannula is provided for insertion into a patient's blood vessel with the IV cannula secured to an IV hub, as can be seen in U.S. Pat. No. 5,951,525 to Thome et al for example, and a flexible tube extending from the IV hub to a second cannula, onto which is typically mounted a needle holder. The second cannula is used to pierce the septum of an evacuated blood collection tube or blood bag so that blood is transferred thereinto via the two cannulae and the connecting tube. The septum is typically a resealable pierceable elastomeric stopper.

As with most, if not all, sharp medical devices which are inserted into a patient (e.g., syringes; catheters; scalpels), inadvertent “sticks” by a needle cannula of a blood collection set into a practitioner post patient-insertion have become a major health concern, particularly with respect to the transmission of blood-borne diseases (e.g., HIV). Various needle shielding and capping devices have been developed in the prior art to wholly, or at least partially, encapsulate used needle cannulae and prevent inadvertent contact therewith. Many of these devices require additional effort by a practitioner to be practiced, ranging from slipping a cap over the used needle cannula to activating a mechanism that drives a shield about the needle cannula.

While the benefits of such shielding and capping devices are apparent, such devices can in some cases contain relatively bulky, rigid components and mechanisms in the area of the IV cannula hub. These components and mechanisms generally add weight, sometimes obstruct vision and may also act undesirably against the skin, all of which may contribute to the IV cannula having an upwards rotation force element while in the vein, which may cause pain and/or necessitate securement of the device against the skin. These potential drawbacks are amplified when the device is used on a small child, infant or premature baby. These negative aspects may detract from the utility of such devices and can cause some phlebotomists to select alternative medical devices without safety features.

Devices having the functional and safety features of existing devices, but without the potential drawbacks noted above, would therefore be desirable.

SUMMARY OF THE INVENTION

In one aspect, the invention is a medical device which includes flexible tubing having a distal end and a proximal end and at least a first lumen extending from said distal end to said proximal end; a first needle cannula having proximal and distal ends, said first needle cannula being mounted at said distal end of said tubing and in fluid communication with said lumen; a second needle cannula mounted at said proximal end of said tubing and in fluid communication with said lumen; a shield disposed over said tubing, said shield extending substantially the entire length of said flexible tubing, and said shield being movable relative to said first needle cannula from an initial proximal position wherein said first needle cannula is exposed to a distal position wherein said distal end of said first needle cannula is covered by said shield. Typically, the device further has an actuator for actuating the shield at a location spaced from the first needle cannula, preferably closer to the second needle cannula than to the first needle cannula.

According to embodiments of the invention, passive or manual activation of a safety shield can be achieved. With passive activation, no additional effort outside of normal operation of the medical device is necessary to cause needle shielding. If desired, manual activation of the safety shield can be provided as an alternative, or in addition, to passive activation. The invention is applicable to various medical devices, but is particularly well-suited for intravenous infusion sets and blood collection sets. For illustrative purposes, discussion herein will relate to embodiments directed to blood collection sets.

These and other features of the invention will be understood through a study of the following detailed description and accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION

According to an embodiment of the invention, with reference toFIGS. 1-4, a medical device10is depicted (as shown therein, a blood collection set), which generally includes;

Flexible tubing11, having a distal end12and a proximal end13and a first lumen14for communicating the first and second needle cannulae15and18. Typically the flexible tubing has an outside diameter of 1 centimeter or less and is easily flexed or bent along the longitudinal axis of the tubing by a user or by the weight of the device itself. The tubing11may be fixed to the first and second needle cannulae15and18using any technique known to those skilled in the art. In the embodiment ofFIG. 1, the first and second cannulae are directly bonded to the flexible tubing11with a suitable adhesive.FIG. 4shows an alternative embodiment in which tubing11is bonded indirectly to the second needle cannula18by additional mating elements such as a luer142and a non-patient needle hub123. Advantageously, as reflected in the embodiments ofFIGS. 1,4,5and7there is no IV cannula needle hub, thereby reducing the weight and bulk of the IV end of the blood collection set of the invention when compared to traditional blood collection set designs.

The needle cannulae15and18are formed in any known fashion such as by drawn metal tubes or molded elastomers. The first needle cannula15includes a sharp distal end17for insertion into a patient and a proximal end16. A proximal end3of the second needle cannula18may also be sharp to facilitate piercing of a septum of a blood collection device (e.g., evacuated blood collection tube; blood bag). The second needle cannula18may also be ensheathed in a compressible elastomeric sleeve20, which acts to seal the proximal end3of the cannula18from leakage, e.g., in the case of multiple sample containers such as multiple evacuated tubes, as known in the art. Both needle cannulae15and18are formed hollow and are fluid communication with each other via the first lumen14. For example, when the second needle cannula16is inserted into an evacuated blood collection device, the vacuum therein draws blood through the first needle cannula15, the lumen14, and the second needle cannula18and into the blood collection device.

At least one wing21may be attached to the shield19. The wing may be used for gripping during insertion and/or for securing the blood collection set to a patient during collection. Advantageously, the wing or wings21are formed from a thin flexible thermoplastic material that provides sufficient surface area for gripping by a user and/or securement to the patient's skin, but at a reduced bulk and weight at relative to conventional blood collection sets. Suitable materials for such wings include Poly Vinyl Chloride, Polyamide, Polypropylene or Polyethylene. Alternate materials for such wings may include thin flexible non-thermoplastic materials such as paper.

The embodiment ofFIGS. 1 to 3includes a needle holder22to which the flexible tubing11is mounted directly by bonding. As known in the art, the needle holder22generally provides a cylindrical body23formed to accommodate an evacuated blood collection tube (not shown) and a forward end/fitting/region adapted to accommodate a needle cannula for piercing the septum of a collection device.FIG. 4shows another embodiment wherein the second needle cannula118is secured to a non-patient needle hub123that is in turn secured to the needle holder122. The non-patient needle hub123is shown inFIG. 4with a threaded connection, but other securement techniques are also possible, e.g., a snap-fit connection. According to the embodiment ofFIG. 4, the flexible tubing111is bonded to a luer142mounted onto the non-patient needle hub123of the needle holder122.

According to an embodiment of the invention, the shield19is disposed over the flexible tubing11, and extends substantially the entire length of the flexible tubing11. Typically, the shield length will be at least 80% of the entire length of the tubing, more typically at least 90%, and advantageously at least 95%. The shield may be formed from any suitable material such as thermoplastic polymers, elastomers or metallic mesh. The shield may have a variety of configurations. It may be for example, a continuous solid along its length that is formed as a single component or as separate multiple components that are joined together (as in the embodiments ofFIGS. 1 to 6) or may be discontinuous e.g., a series of interconnected links or segments801which are joined by a series of hinges802(as shown from above inFIG. 8and from the side inFIG. 9), or configured with tubular elements901at either end thereof (to provide shielding and actuation function) connected by one or more linear lengths902(as shown inFIG. 10). Generally, the shield is disposed telescopically over the tubing.

A shield drive mechanism24is typically provided to move the shield19relative to said first needle cannula15from an initial proximal position (SeeFIG. 2) wherein said first needle cannula15is exposed, to a distal position (SeeFIG. 3) wherein said distal end17of said first needle cannula is covered by said shield19. The shield drive mechanism24may be of any design which causes relative movement between the shield19and the first needle cannula15in urging the shield19into a distal position covering the first needle cannula15. The shield drive mechanism may include, for example, a bias element such as a spring66, or elements to facilitate or simply allow manual movement of the shield.

In the embodiments ofFIGS. 1-4, the safety shield requires manual activation. The shield drive mechanism24includes a bias element (spring66), a housing25, an actuator (a resilient latch26), a proximal position locking member27and a distal position locking member28. The shield19has2regions of different cross section. The first region76has a cross section which encompasses the flexible tubing11but is smaller than the internal diameter of the spring66, while the second region77has a cross section that is larger than the outer diameter of the spring. The second region77of the shield thus encompasses both the spring66as well as tubing11and is located within the housing25when the shield19is in the proximal position. An annular wall78is formed at the interface of the two regions of different cross section of the shield19. Spring66is located between the outer surface of flexible tubing11and the shield19; the proximal end of the spring66is retained against the proximal wall75of the housing25while the distal end of the spring66exerts the urging force on the annular wall78. The shield is retained in the proximal position by the interaction between the resilient latch26and the proximal position locking member27. The resilient latch26has an inherent positive bias towards engagement with the proximal position locking member27when the shield is in the proximal position and with the distal position locking member28when the shield is in the distal position. Removal of the latch26from the proximal position locking member27by the user, is effected by lifting the latch26out of engagement with the proximal position locking member27, which allows spring66to drive the relative movement between the first needle cannula15and the shield19in a distal direction from the proximal position to the distal position. The distal movement of the shield19is arrested at the distal position by the engagement of the actuator26in the distal position locking member28, through the inherent positive bias of the latch as described above. The shield19is then locked in the distal position.

The embodiment ofFIGS. 5 and 6, show another type of shield drive324. This mechanism is a manual shield drive mechanism324in which the actuator (a finger grip333) is manipulated by the user's hand and physically moved to actuate shielding. Actuator333is located in proximal stop332of housing335before use thereby securing the shield319in the proximal position. After or during collection of the blood sample, the actuator333is manually manipulated out of proximal stop332and along slot330in housing335in a distal direction, and into distal stop331thereby advancing the shield over the IV needle cannula315and securing it in the distal position.

FIG. 7shows another embodiment which uses manual manipulation to effect needle shielding. The user grips the shield419at any point along its length and physically pushes the shield in a distal direction from the proximal position to the distal position along the tubing411. In this embodiment, the shield drive mechanism is therefore the shield exterior and does not contain, or require an actuator however at least one latch (not shown) maybe present to retain the shield419in the proximal position and distal position.

The actuator, if present, can be a push button, a latch or a finger grip, for example, is used to actuate the shield drive mechanism through either manual or passive activation. A push button is any element that effects actuation of the shield drive mechanism via a pushing force. A latch is any element that effects actuation of the shield drive mechanism by disengaging an element from a retaining feature such as a notch, hole, or lug. Note that an example of a latch26/126is shown inFIGS. 1-4. A finger grip is any element that effects actuation of the shield drive mechanism by translating force from one or more of a users' digits to the shield.FIGS. 1 to 6show that the location of an actuator is typically spaced from the first needle cannula. However the actuator can be located anywhere along the length of the shield particularly for a manually activated safety shield, but it is advantageous for the actuator to be located closer to the second needle cannula than to the first needle cannula. If a bias element is present in the shield drive mechanism, the actuator will typically be located closer to the second cannula.

Another embodiment uses passive activation to effect needle shielding. An actuator is provided for releasing the shield from the proximal position and enabling a biasing element to propel the shield to the distal position. The actuator may be actuated automatically and passively in response to an operational condition indicative of use of the blood collection set. For example, the blood collection set intended for use with an evacuated tube may have an actuator located through the distal wall of the needle holder, which is actuates the shield drive mechanism by the movement of an evacuated tube into communication with the proximal end of the needle cannula. As can be seen in U.S. patent application Ser. No. 10/369,790 to Conway for example.

As will be readily recognized by those skilled in the art, any design or configuration can be used to translate manual or passive activation of the safety shield into movement of the shield.

While the invention has been described in relation to the preferred embodiments with several examples, it will be understood by those skilled in the art that various changes may be made without deviating from the spirit and scope of the invention as defined in the appended claims.