Needle protector sheath

A needle protector sheath comprises a body having a top wall, sidewalls and open ends. A slot is formed in each sidewall to slidingly receive a needle wing extending through each of the slots. Typically the slots extend through one end of the protector sheath. The protector sheath also defines an open, bottom aperture extending from end to end of the body, to permit the sheath to be laterally applied to tubing connected to a winged needle and to be advanced to a position where the needle tip is recessed in the sheath and the needle wings extend through the slots. In another embodiment an elongated anchor member may extend forwardly from the body to be manually pressed to retain the protector sheath as the needle is being withdrawn from the skin of a patient. The anchor member may have an outer end portion that bends away from the patient in position of use. Also, a novel sheath design and slot arrangement is disclosed.

BACKGROUND OF THE INVENTION 
Utterberg et al. U.S. Pat. No. 5,112,311 discloses a sliding body or sheath 
which is carried on a tubular set such as a fistula set for hemodialysis, 
having a winged needle at the end. There is a significant need to provide 
the maximum amount of protection to medical personnel against needle 
sticks, especially with respect to needles that are used in contact with 
blood. The sliding sheath of the cited patent can be brought forward to 
enclose the needle as the needle is retracted from the patient, so that 
the needle is immediately secured against accidental needle sticks by the 
sliding device. The wings of the needle, which are commonly used in 
conjunction with a variety of intravenous needles, slide within opposed 
slots of the needle protector of the cited patent, and are locked in place 
when the needle is fully withdrawn into the sliding sheath as described. 
By this present invention, improvements are provided to the device 
disclosed in the above-cited patent. Specifically, the device of the prior 
art is typically placed on a needle set prior to use and the wings engaged 
in the slots. Even when the sliding sheath is retracted away from the 
needle as much as possible, medical personnel have found its presence to 
be inconvenient during the process of venipuncture and taping of the 
needle wings to the skin of the patient. 
Also, by this invention, improvements in functioning are achieved by a 
modification of the shape of the slots of the sliding sheath or body 
through which the needle wings penetrate. Particularly, withdrawal of the 
needle from the patient can be facilitated in an axial movement, reducing 
the potential for the point to cause a hematoma. Also, advancement of the 
sheath about the needle is facilitated. 
Thus, significantly improved needle protector sheaths are provided, some of 
which can be applied to a needle and attached tubing after the needle has 
been inserted into the vein of a patient. Additionally, other improvements 
over the prior art are found herein. 
DESCRIPTION OF THE INVENTION 
In accordance with this invention, a needle protector sheath is provided 
which comprises a body having a top wall, side walls, and at least 
partially open ends. A slot is formed in at least one of the walls, and 
preferably in each side wall, to slidingly receive a needle wing extending 
through each of the slots. The protector sheath may define an open, bottom 
aperture extending from end to end of the body to permit the sheath to be 
laterally applied to tubing connected to a winged needle. After such 
lateral application, the sheath or body can be advanced in sliding manner 
along the tubing to a position where the needle tip becomes recessed in 
the sheath, and the needle wing or wings extend through the slot or slots 
present. Thus some types of the sheath of this invention can be mounted on 
a needle set after the needle has been placed in a vein or a fistula. 
Detents may be provided on the side walls adjacent the bottom aperture to 
help retain a winged needle, and its connected tubing, within the body of 
the protector sheath. The bottom aperture is proportioned to permit a 
needle, needle hub or its connected tubing to be inserted through the 
bottom aperture for laterally installing the protector sheath onto the 
tubing of the needle set. 
The body of the protector sheath may further define a needle tip retaining 
wall which is typically formed between the top and side walls adjacent to 
one end of the body. Such a retaining wall may be positioned substantially 
parallel to the longitudinal axis of the body to define a closed pocket 
with the remainder of the body, for receiving a pointed needle tip which 
is carried within the protector sheath. This provides an added, desired 
sequestering of the needle tip for improved safety. Alternatively, the 
retaining wall may be positioned at an acute angle, for example about 
30.degree. to 60.degree. to the longitudinal axis of the body, which also 
defines a closed pocket with the remainder of the body for needle tip 
retention. If desired, the retaining wall may be essentially perpendicular 
to the longitudinal axis of the body (or in fact, it may be a partial 
front wall) to form a barrier wall against which the needle tip may 
impinge, for further protection against accidental needle sticks. 
It also is desirable for the slots of the protector sheath body to extend 
toward the sheath bottom as they extend toward an open slot end at one end 
of the body. This has been found to facilitate the easy withdrawal of a 
needle emplaced in the venous system of a patient, with the needle tip 
directed in the direction of the one end of the body. As the needle is 
withdrawn, the needle protector can receive the needle wings in the slots. 
Because of the curve of the slots toward the bottom of the body, the 
needle wings are more easily received and engaged by the slots as the 
needle is withdrawn, with the needle protector sheath being held 
stationary, so that the needle may be withdrawn rearwardly into the needle 
protector sheath. The slots preferably extend through one end of the body 
at the slot end nearest the bottom aperture. 
As another aspect of the inventions disclosed herein, an elongated anchor 
member can extend forwardly from the body to be manually pressed to retain 
the protector sheath as the needle is being withdrawn from the skin of a 
patient, as broadly disclosed in the cited U.S. Pat. No. 5,112,311. By 
this invention, the anchor member may have a straight, major portion 
comprising most of the length of said anchor member. Also, the anchor 
member may define an outer end portion that bends away from the patient in 
position of use, typically as a curved shape rather like the tip of a ski. 
Thus, when the sheath of this invention is being advanced toward a 
position to receive the needle when the needle is to be withdrawn from the 
patient, the anchor member more easily slides over adjacent bandages and 
the like. 
Preferably, the anchor also comprises a substantially flat, sheath-like 
extension of the top wall. Also, the anchor may join the top wall at a 
junction line which is defined by a line of bending weakness, to 
facilitate its downward bending when manually pressed. 
The body of the protector sheath, which may be rectangular in 
cross-section, is preferably tapered by about 0.2 to 5 degrees to define a 
forward end of the body that is of less cross-sectional dimension than a 
rear end of the body. This small amount of tapering or "draft" facilitates 
the molding of the sheath. 
It is also a preferred embodiment for the slots to extend through a forward 
end of the body with the slots each defining upper and lower surface. A 
major portion of the slots preferably defines an acute angle to the 
longitudinal axis of the needle protector sheath so that most of the 
extent of the slots extends in such an acute angular relationship. Forward 
end portions of the lower slot surfaces extend at an acute angle to the 
longitudinal axis of the body, to intersect the forward body end at a 
position that is substantially maximally spaced from the top wall. In 
those circumstances where a bottom wall is present, the lower slot 
surfaces preferably merge with the inner surface of a forward end portion 
of the bottom wall, to achieve such maximal spacing. The forward end 
portions of the upper slot surfaces may diverge from the lower slot 
surfaces and extend toward the top wall. Thus, wide slot portions are 
provided in each sidewall at the forward body end, which slot portions 
taper inwardly to communicate with the remainder of the slots, which 
remaining portions are substantially narrower. Thus, it becomes easy to 
advance the sliding sheath so that the front end thereof engages and 
captures the projecting wings of a needle hub, with the wings projecting 
outwardly through the slots. 
Preferably, a major portion of each of the slots defines an acute angle to 
the longitudinal axis. Also, most of the length of the slots may be 
straight. 
Thus, needle protector sheaths are provided which exhibit significant 
improvements in structure and functioning over those of the prior art. 
The terms "top", "bottom", and "side" as used herein are relative and 
exemplary in intent, and are not intended to exclude the use of a 
protector sheath of this invention in a different or varying position of 
spatial orientation.

DESCRIPTION OF SPECIFIC EMBODIMENTS 
Referring to FIGS. 1 through 8, a needle protector sheath 10 is disclosed, 
being generally similar in structure and function to the needle sheaths 
shown in U.S. Pat. No. 5,112,311 except as otherwise described herein. 
Sheath 10 comprises a body 12 which has a top wall 14 and side walls 16, 
18, plus an optional gripping rib 20, integral with top wall 14, to 
facilitate manual gripping of the protector sheath. Apart from the 
presence of gripping rib 20, body 12 is shown by FIGS. 3 and 4 to be of 
generally U-shaped or C-shaped cross-section, defining an open bottom 
aperture 22 which extends from end to end of body 12. 
Sheath 10 also defines a pair of slots 24, each slot 24 being defined in a 
separate side wall 16, 18, with each slot 24 extending through an end 23 
of body 12. The purpose of slots 24 is to receive therethrough the wings 
26 of a winged needle hub 28 projecting therethrough which, in conjunction 
with needle 31, is generally referred to herein as a "winged needle" 30. 
The winged needle 30 is shown to be connected to flexible tubing 32 of a 
fistula set used in hemodialysis, for example. 
In the cited prior art patent, the needle protector sheath shown therein 
may be mounted upon tubing of a fistula set or the like from the needle or 
tube end of the set, to enclose completely the needle and/or hub with at 
least one end of the guard. It is then advanced distally to enclose the 
needle as the needle is being withdrawn from the patient. Specifically, 
the prior art protector sheath can be mounted on the winged needle of a 
set by passing the needle through the proximal end of the needle protector 
sheath, and then moving the sheath rearwardly out of the way of the 
needle, with the wings sliding into and along the slots of the protector 
sheath. 
Locking detents 25 are provided with a distally facing angled surface 27 
and a proximally facing perpendicular surface 29, so as to provide snap 
fit retention for the wings sliding in slots 24 after the winged needle 30 
has entered into fully enclosed relationship with protector sheath 10, as 
shown in FIG. 1, for the substantially permanent enclosing of the needle 
in the sheath. 
As an advantage, the protector sheath of this invention is capable of being 
mounted on the tubing 32 of a fistula set from the side, even after the 
needle has been positioned in the vascular system of a patient, without 
the need for access to an end of the set. Instead, one can simply place 
the protector sheath laterally about tubing 32, with the tubing being 
retained to an extent by detents 34. Then, the protector sheath may slide 
forwardly relative to the needle as the needle is withdrawn, so that the 
needle becomes immediately enclosed by the protector sheath. This can be 
accomplished, as taught in the previously cited patent, by pressing a 
finger against projecting anchor 36, which may be an integral part of 
protector sheath 10, so that as the needle is withdrawn, the protector 
sheath is held in stationary position, causing the needle to retract into 
the sheath. 
Because slots 24 may have a downward curve at their forward portions 38, it 
becomes easier for the forward open slot portions 38 to each engage a 
respective wing 26 as the winged needle 30 and body 12 are brought 
together, as implied by the different needle positions of FIGS. 6 and 7. 
Body 12 is of identical design to that of the previous embodiment except 
for the deletion of anchor 36. Thus, the proximity of the forward end 38 
of each slit 24 to the lower edge of body 12 facilitates convenient 
engagement of the needle wings for withdrawal of the needle without 
excessive movement of needle 31 in the tissue 40 of the patient. Hence, 
the protector sheath of this invention can be applied to a needle which is 
being withdrawn with less patient discomfort. Also, forward slot ends 38 
may be outwardly flared to more easily engage and receive the respective 
wings 26. 
It can also be seen that slot 24 has a rear or proximal end 42 which also 
exhibits a slope toward the bottom edge 43 of body 12. The effect of this 
slope is to cause needle 31 to tilt upwardly as shown in FIG. 7. Then, 
body 12 can be retracted again relative to needle 31 to cause needle 31 to 
reside in the pocket 44 which is defined by needle tip retaining wall 46, 
as particularly shown in FIG. 8. 
Needle tip retaining wall 46 is shown to be positioned substantially 
parallel to the longitudinal axis of body 12, to define a closed pocket 44 
with the remainder of the body, for retention of the pointed tip of needle 
31. Alternatively if desired, retaining wall 46 may extend at about a 
45.degree. angle to the axis of body 12, as shown in dotted lines in FIG. 
7 to provide a more open pocket 44. Also if desired, retaining wall 46 may 
be substantially perpendicular to the axis of body 12, while being short 
enough to not completely obstruct the forward aperture 48 of body 12, to 
provide an obstructing wall for the needle point. 
Referring to FIG. 9, a protector sheath 10a is shown having a body 12a 
which may be of a design similar to that of the previous embodiments. In 
this particular embodiment, slots 24a on both sides of the side walls 
curve downwardly to pass through the lower edge 43a of body 12a, rather 
than passing through the end thereof as in the previous embodiments. 
Beyond that, the construction and use of protector sheath 10a can be 
similar or identical to the construction and use of the previous 
embodiments. 
Referring to FIGS. 10 through 12 another embodiment of the protector sheath 
10b is shown, being similar in structure and function to the embodiment of 
FIGS. 1 through 8 except as otherwise disclosed herein. 
Body 12b is of U-shaped configuration as shown in FIG. 12, defining open 
bottom aperture 22b as before. Slots 24b are defined in each sidewall, 
while anchor 36b is also provided as before. 
In this embodiment, locking detents 25b are an integral part of the 
remainder of sheath 12b, but in this embodiment, the locking detents do 
not project outwardly to the side, but rather project into each slot 24b 
in such a manner that a retracting wing of a needle can cause deflection 
to pass through locking detents 25b to be permanently secured in distal 
slot section 50 to lock the needle therein. It can be seen in this 
embodiment that needle tip retaining wall 46b does occupy an acute angle 
to the longitudinal axis in a manner previously discussed with respect to 
an earlier embodiment. 
Detents 34b are used in a manner similar to the corresponding detents of 
the previous embodiments to releasably retain the needle hub 30 or the 
tubing attached thereto within the U-shaped protector sheath. 
Also, the needle protector sheath 10b carries a pair of spaced gripping 
flanges 52 instead of a single gripping member as in previous embodiments, 
the gripping flanges 52 being positioned adjacent the proximal end of the 
sheath. This better facilitates the gripping of the sheath, which is 
rather small. A single, central gripping member would have to be unduly 
large relative to the typically fairly small sheath of this invention. 
Gripping members 52 facilitate gripping of the sheath without the need for 
an oversized, single gripping member which would resemble a huge dorsal 
fin. 
Referring to FIGS. 13 through 18, sliding needle protector sheath 60 is 
shown as a single molded piece comprising a body 62 having a top wall 64, 
a pair of sidewalls 66, a bottom wall 67, and open ends as shown in FIGS. 
16 and 18. Body 62 is shown to be of rectangular shape, defining an inner 
bore 69 for receiving a winged medical needle. 
A slot 70 is defined in each of sidewalls 66, with each slot being of 
substantially identical shape and positioning to the other slot in the 
other sidewall 66. It can be seen that each slot 70 is open to the forward 
end 68 of body 62 particularly, intersecting the forward end 68. Each slot 
70 defines upper and lower surfaces 72, 74. Most of the pair of lower slot 
surfaces 74 of the respective slots 70 are shown to extend straight and at 
an acute angle to longitudinal axis 76 of body 62, to encounter the 
forward body end 68 at a position that is substantially maximally spaced 
from top wall 64; i.e., the distance between bottom wall 67 and lower slot 
surface 74 at end 68 is preferably a substantial practical minimum in 
light of the particular engineering and economic considerations for 
manufacture of the specific sheath 60. Typically, the spacing between 
surface 74 and the bottom surface of bottom wall 67 will be no more than 
about 3 millimeters at end 68, preferably no more than about 1 millimeter. 
The forward end portion of the upper slot surfaces 72 of the respective 
slots 70 can be seen to diverge from the forwardly positioned lower slot 
surfaces 74, to define a pair of wide slot portions 76 at forward body end 
68. The respective portions 76 of slots 70 taper inwardly as the slot 
portions extend rearwardly from forward end 68, to communicate with the 
remaining portions 78 of slots 70. It can be seen that remaining portions 
78 of slots 70 comprise the major portions of the respective slots 70, and 
in this embodiment are substantially straight along most of their length. 
A wing-catching slot recess 80 receives and retains the respective needle 
wings when protector sheath 60 is advanced into needle-enclosing position. 
Slot recess 80 may be shaped to receive the desired needle wings, and to 
effectively permanently hold them in retained relation so that the sheath 
is locked in place around the needle in a manner similar to that of the 
prior art. 
Thus, as sheath 60 is advanced along a set tube to effectively "swallow." a 
winged needle which is emplaced in a patient, the forward end 68 of bottom 
wall 67 can easily slide underneath the emplaced needle hub without 
causing the patient pain. At the same time, the wide, tapered slot portion 
76 effectively facilitates the capture of the wings, to guide them to the 
straight portion 78 of each slot 70 as sheath 60 is advanced. The major 
portion of slot 70 occupies an acute angle to axis 77 to approximate the 
orientation of the needle in the patient, so that the needle is not bent 
or twisted as sheath 60 is advanced. 
Anchor member 82 is carried as an extension of top wall 64, extending 
forwardly of sheath body 62, as shown, and used as described in U.S. Pat. 
No. 5,112,311. In this embodiment anchor 82 comprises a flat, 
substantially sheetlike extension of top wall 64, separated therefrom by a 
junction line 86 which defines a line of bending weakness, produced by the 
presence of a transverse groove extending partway through the plastic wall 
to create a hinge effect. 
Also, anchor member 82 defines an outer end portion 88 which bends away 
from the patient in position of use, bending also away from bottom wall 
67, as shown in FIG. 15. Thus, anchor 82 is rather of the shape of the 
front end of a ski, with curved end 88 functioning in the manner of a ski 
to pass over bandages of varying thickness and the like as the sheath 60 
is advanced toward the needle while emplaced in the patient. Projections 
89 facilitate manual retention while the anchor is being pressed against 
the patient and the needle being withdrawn. Junction line 86 facilitates 
the downward bending of anchor member 82 as it is pressed against the 
patient. 
Thus, one may manually and easily press anchor 82 against the patient's 
skin and intervening bandages to retain protector sheath 60 as the needle 
is being withdrawn from the skin of the patient. The wings of the needle 
hub are captured by and move rearwardly along slots 78 until they enter 
slot portions 80, where they are locked in place. In this position, the 
needle is enclosed within the body 62 of the sheath, safely away from the 
risk of inflicting harm. 
The rectangular cross-section of this embodiment permits the needle sheath 
to stand up easily on a surface, while at the same time the needle is 
completely enclosed within sides of the body 62 after the sheath has been 
advanced around the needle. 
The above has been offered for illustrative purposes only, and is not 
intended to limit the scope of the invention of this application, which is 
as defined in the claims below.