Patent Application
20060089599
The present invention relates to a medical needle assembly of the type commonly used in both manual and automated blood donations. More particularly, the present invention relates to a needle cover for a medical needle that provides evidence of product tampering, allows for sterilization of the needle, and protects the needle from damage, such as bending.
Blood collection kits, in their most basic form, typically include a collection container for receiving blood from a donor, a tube that provides a flow path from the blood donor to the collection container and a hypodermic needle attached to one end of and in flow communication with the tubing. The needle assembly typically includes a needle attached to a needle hub which allows for manipulation of the needle assembly by the technician.
Donor needles are commonly shielded before and after their use with a removable needle cover. Shielding the needle protects the technician from inadvertent contact with the sharpened needle tip. Shielding the needle also protects the needle from damage during shipping and transport. Shielding also preserves the sterility of the needle prior to use and ideally maintains the integrity of the closed system by preferably providing a hermetic seal between the needle cover and needle assembly. The needle cover may also provide assurance to the end user that the needle has not been tampered with.
Needle covers typically include an elongated sleeve with an inner bore for receiving the needle. The needle cover is typically made of a plastic material with sufficient rigidity to protect the needle from damage, such as, but not limited to, bending. Preferably, the plastic material is permeable to moist heat, allowing for steam sterilization, the preferred form of sterilizing many medical products. The needle cover seals to the needle hub post in a way that provides the user with evidence of tampering.
Examples of needle assemblies including associated needle covers are provided in U.S. Pat. No. 4,402,682 and U.S. Pat. No. 4,496,352, both of which are assigned to the assignee of the present application and incorporated herein by reference. These patents disclose a needle assembly including a cannula, (i.e., needle) attached to a hub and to donor tubing. The needle covers are made of a plastic material, which forms a thermal bond with the post of the needle hub to provide a tamper evident seal. The needle covers described in the above-referenced patents also include an internal plug within the bore of the needle cover and located at the distal end of the needle cover. The plug is made of a resilient material and includes a pocket for enveloping and protecting the distal needle tip.
Another example of a needle assembly and associated needle cover is disclosed in U.S. Pat. No. 4,551,138. The needle cover disclosed therein includes a hollow body made of a sterilizable plastic material. The needle cover includes a resilient “layer” made of a polymeric elastomer located near the proximal open end of the needle cover. The diameter of the cylindrical resilient layer at the proximal end of the cover has a diameter that is smaller than the diameter of the needle post engaged by the needle cover. The needle cover is placed over the needle and engages the post of the needle hub. According to U.S. Pat. No. 4,551,138, a hermetic seal is formed between the needle cover and the hub or post portion of the needle assembly.
While the above-described needle covers have worked satisfactorily, they are not without drawbacks. For example, the need for a needle cover that is sufficiently rigid to protect the needle from damage (which may occur during shipping) often means having to use a plastic material that is less than ideally suited for effective steam sterilization. Consequently, this may result in longer sterilization cycles which may have a deleterious effect on other components of the blood processing set. In addition, a needle cover made of a more rigid plastic may also be less desirable in that contact between the needle tip and the hard plastic can result in dulling of the needle tip. On the other hand, while a needle cover made of different, preferably more resilient plastic may be more desirable from a sterilization and tip protection standpoint, it may not offer sufficient stability and protection against bending or bowing.
Thus, it would be desirable to provide a needle cover that is sufficiently rigid to protect the needle from damage or bending, but that still allows for effective sterilization, can still provide evidence of tampering, and is cost effective to manufacture.
In one aspect, the present invention is directed to a needle assembly that includes a hub assembly, a needle having a distal end and a proximal end, attached to the hub assembly at its proximal end. The needle assembly further includes an attachable and removable needle cover for enclosing the needle. The cover includes an elongated inner sleeve portion and elongated outer sleeve portion whereby the inner sleeve portion engages the hub assembly and provides evidence of tampering.
In another aspect, the present invention is directed to a needle cover for a medical needle. The needle cover includes a proximal end and a distal end. The needle cover further includes an outer sleeve portion made of a first plastic material having an open proximal end, and an inner sleeve portion associated with the outer sleeve portion that likewise includes an open proximal end. The outer sleeve portion has an inner diameter greater than the outer diameter of the inner sleeve portion at their proximal ends.
In another aspect, the present invention is directed to a needle cover for a medical needle where the cover includes a proximal end and a distal end. The needle cover includes an outer sleeve portion made of a first material having an open proximal end and an inner sleeve portion made of a second plastic material having an open proximal end. The needle cover further includes at least one window in the outer sleeve portion through which the inner sleeve is exposed.
In a further aspect, the present invention is directed to a needle cover for a medical needle that includes an elongated body having an outer surface and an inner surface and an open proximal end for receiving a needle and a closed distal end. The body of the needle cover defines an interior bore. The inner surface has a modulus lower than the modulus of the outer surface.
In another aspect, the present invention is directed to a medical needle assembly including a needle cover and a needle hub assembly. The needle hub assembly includes a hub and a needle post that extends through the interior of the hub. A medical needle is attached to the post. The post includes a beveled sealing ring adapted for engaging the needle cover. The hub includes gripping members on the outer surface thereof.
Turning now to the Figures,
Set 10 may further include a sampling unit, generally designated by reference numeral 30, for collecting samples of the donated blood. Sampling unit 30 may include a sampling container 32 and a sample tube holder 34. Flow control through the disposable set 10 is achieved by manipulating flow control clamps 38. Details of the blood collection, the collection set and blood sampling are described in U.S. Pat. No. 6,387,086, which is incorporated herein in its entirety by reference, and in the aforementioned U.S. patent application Ser. No. 10/956,296, previously incorporated by reference.
Needle 44 is attached to hub assembly 41. Hub assembly 41 includes hub 40, which is compact and easily manipulated between the fingertips of the technician. Hub assembly 41 may further include needle post 42 which, as shown in
Hub 40 further includes an inner bore 43, for receiving hollow needle post 42 which receives or is otherwise attached to needle 44. As shown in
In one embodiment, hub 40 may include an outwardly projecting ridge 48, which extends axially along one exterior surface of hub 40. Ridge 48 serves as a reference point for the proper alignment of the beveled end 45 of needle 44 during assembly, as shown, for example, in
Hub 40 is preferably made of a flexible material, compressible by the fingers of the technician. This enables the technician to effect a firm finger grip on the hub 40 and to carefully maneuver and control the hub for fast and comfortable venipuncture. Preferred materials for hub 40 include polyvinylchloride or thermoplastic elastomers. Particularly preferred is low modulus and low durometer polyvinylchloride.
Alternative embodiments of hub 40 are shown in
Proper needle orientation during assembly and venipuncture may be ensured by aligning the beveled end 45 of needle 44 with a selected surface of hubs 140, 240, 340 or 440. In one embodiment, hub surface 143, 243, 343 or 443 serves as a visual reference point to ensure that the needle bevel 45 and heel 47 are properly oriented (i.e., facing up). Although not shown in
Turning briefly to
As shown in
The needle assembly of the present invention further includes an attachable and removable cover 46. As shown in
Outer surface 56 of cover 46 may include one or more gripping members or gripping means to provide the user with a better grip of needle cover 46 during capping, recapping and uncapping. In one embodiment, outer surface 56 of cover 46 may be made with or subsequently treated to provide a rougher or coarser surface. In another embodiment, outer surface 56 may be provided with one or more gripping members. In a preferred embodiment, gripping member(s) may be one or a plurality of axially extending raised ribs 68 which project from the outer surface 56 of cover 46. Ribs 68 facilitate gripping of cover 46 by the user during removal and capping. The number of ribs can vary, although in a preferred embodiment, four ribs equally spaced (i.e., separated by 90° intervals) are preferred. Cover 46 may also include one or more windows 66 between ribs 68, discussed further below.
Turning now to
In one preferred embodiment, outer sleeve portion 60 is made of a polymeric material such as, for example, polyolefin, acrylic or other plastic material that is sufficiently rigid to protect needle 44 from damage, and that is compatible with the material of inner sleeve portion 62. For example, in one embodiment, the plastic material of outer sleeve portion 60 may have a Young's modulus of at least approximately 50,000 psi and a preferred Young's modulus of approximately 50,000-450,000. More preferably, the plastic material of outer sleeve 60 may have a Young's modulus of approximately 80,000-220,000 psi. Preferred materials include, but are not limited to high density polyethylene, polyacetal, PET, polycarbonate, rigid and semi-rigid polyvinyl chloride and polypropylene.
The material of outer sleeve portion 60 may have a hardness of at least approximately 95 Shore A. In one embodiment, the hardness of the outer sleeve material may be between approximately 100 Shore A and up to, for example, a Rockwell Hardness of 120 R Scale. In a preferred embodiment, outer shell sleeve 60 may be made of polypropylene with a Rockwell Hardness (durometer) of approximately 110 R Scale.
In addition to providing the desired rigidity, the plastic material of outer sleeve portion 60 should also be one that will not stick to other parts of the disposable blood processing set as a result of the sterilization process or simply from storage of the product prior to use. In this regard, polyolefins such as polypropylene, are preferred.
Inner sleeve portion 62 may be made of a medical grade plastic material that preferably is softer (and, thus, has a lower modulus) than the material of outer sleeve 60, and is also sterilizable by moist heat sterilization (i.e., autoclaving). Preferably, the plastic material of inner sleeve 62 may have a Young's modulus of less than approximately 50,000 psi, with a preferred Young's modulus range of approximately 1,000-50,000 psi and a more preferred range of approximatley 5,000-35,000 psi. The plastic material of inner sleeve portion 62 may also have a durometer of approximately 60-90 Shore A, with a durometer of 70-85 Shore A being preferred. Examples of suitable materials include, but are not limited to, elastomers such as Hytrel® and more preferably, polyvinyl chloride.
Of course, it will be appreciated that the present invention is not limited to the plastic materials (with the hardness and tensile properties) described above. The needle cover of the present invention may include an outer surface or outer sleeve made of any relatively more rigid (i.e., relative to the material of inner surface or inner sleeve portion 62) plastic material sufficient to protect the needle from bending, and an inner surface or inner sleeve in proximity to the needle made of relatively more resilient (lower modulus) material. The materials selected should be capable of being sterilized by the selected form of sterilization (e.g., moist heat), and compatible with each other and with other parts of the needle assembly and blood processing set.
As shown in
Turning now to
The internal diameter of inner sleeve 62 is preferably less than the outer diameter of sealing ring 54. However, because the inner sleeve 62 is typically made of a more resilient plastic material, such as polyvinylchloride, when needle 44 is inserted into cover 46, resilient inner sleeve 62 flexes outwardly as shown in
Because the inner sleeve material (example, polyvinylchloride) is generally compatible with the polymeric material of post 42 (e.g., polycarbonate), during steam sterilization, a thermal bond is formed along the concentric interface of the inner surface of inner sleeve 62 and sealing ring 54. The beveled surface of ring(s) 54 further serve(s) as energy directors during bonding. The thermal bond created is sufficient to allow for removal of cover 46 at the time of use without requiring excessive removal torque, while still providing a sufficient amount of resistance to indicate whether the needle assembly has been tampered with. In addition, the bond formed between post 42 and inner sleeve 62 serves as an effective sterile barrier in that it prevents ingress of bacteria and preserves the sterility and integrity of the closed system. In a preferred embodiment, cover removal should require between approximately 2-24 in.-oz. torque to break the bond.
The present invention provides several benefits over known and presently used needle covers. For example, the present invention provides a needle cover with a substantially rigid outer shell or surface that protects the needle from bending or other possible damage. At the same time, needle cover 46 provides a softer, more resilient interior surface along the entire axial length of the needle 44 which prevents damage to the needle shaft and dulling of the needle tip (which would be possible, due to contact with an otherwise rigid plastic material). The needle cover of the present invention provides these advantages without diminishing the effectiveness of steam sterilization or requiring longer sterilization cycles by allowing for substantial permeation of the needle assembly by the moist heat of the sterilization process (e.g., through windows 66). Thus, the needle can be protected from damage by a relatively rigid outer surface and the needle assembly can still be sufficiently and adequately exposed to the moist heat of steam sterilization, thereby ensuring complete and thorough sterilization of the needle assembly.
In addition, the two-piece construction of the needle cover of the present invention and the preferred molding process by which it is formed (including the proximal gap between the outer and inner sleeves) allows for the secure and hermetic sealing of the cover to the needle post in a way that does not unduly stress the needle cover and results in acceptable removal torque.
The needle assembly of the present invention has been described in the context of its preferred embodiments. The description set forth above is by no means intended to limit the invention, which is recited in the appended claims. Further advantages of the present invention will be apparent to those of ordinary skill in the art.
