Patent Description:
Uncontrolled hemorrhage from trauma remains a major cause of death, both on the battlefield and in civilian situations. Untreated, extreme bleeding as in the case of arterial bleeding can cause hypovolemic shock within just minutes.

Tourniquets are well-known devices used to stop blood loss from trauma. When properly deployed, they provide life-saving support in emergency situations when an injured victim is alone or cannot reach immediate medical attention. A standard tourniquet is a tightly tied or wound band applied around an injured limb in an attempt to increase pressure around the limb, above the injury and stop severe bleeding or uncontrolled hemorrhaging. Rapid application of a tourniquet above the site of injury is paramount to effective hemorrhage control, as is rapid incremental release of a tourniquet once medical assistance is available to provide next-step trauma management.

Many known tourniquets are of the "windlass" type. Such tourniquets typically include a strap threaded through a windlass handle and coupled to a tourniquet base. In order to tighten the tourniquet around the limb, the strap is threaded through a buckle and the windlass handle is twisted creating a knot between the windlass and the base and causing the strap to constrict circumferentially about the limb. It is important to apply and maintain sufficient pressure to the limb to occlude blood flow until the tourniquet is removed.

A drawback to some of these known tourniquets is that sometimes the knot created in the compression strap as the tourniquet handle is twisted becomes too bulky and the windlass tends to fall to one side, limiting the ability to further turn and create additional pressure. If the knot becomes too bulky, it may be difficult for the user to apply sufficient torque.

Even when the user is able to apply sufficient pressure, most windlass tourniquets experience pressure loss or creep of up to <NUM>% during the first five minutes after the tourniquet is applied.

Accordingly, there is a need for a windlass tourniquet that facilitates the application of circumferential pressure and that compensates for natural pressure creep that occurs within minutes of tourniquet application.

From e.g. <CIT> a tourniquet is known, comprising a base, a compression strap, a windlass handle, a locking strap, a triangular shaped handle lock and a strap connector assembly.

The present invention provides a tourniquet with the features according to claim <NUM>. Further preferred embodiments are described in the dependent claims.

Some embodiments of the present invention are illustrated as an example in the accompanying drawings and are described in sufficient detail to enable those skilled in the art to practice the invention. It is to be understood that other embodiments may be utilized and that structural changes based on presently known structural and/or functional equivalents may be made without departing from the scope of invention. The above and other objects, advantage and features of the present invention will be more readily apparent when read in conjunction with the following drawings wherein:.

Now, referring to the <FIG>, a tourniquet <NUM> according to the invention includes a constricting band or compression strap <NUM> attached to/engaged with a base <NUM>. Compression strap <NUM> preferably has a width of between about <NUM>,<NUM> (<NUM> inch) and about <NUM>,<NUM> (<NUM> inches), and more preferably a width of between about <NUM>,<NUM> (<NUM> inch) and about <NUM>,<NUM> (<NUM> inches). In an embodiment, compression strap <NUM> has a width of about <NUM>,<NUM> (<NUM> inches). Compression strap <NUM> has a length that, at a minimum, is sufficient to allow the strap to be wrapped around the limb of an average size adult male.

Base <NUM> is preferably wider than compression strap <NUM>. In accordance with an embodiment of the invention, base <NUM> has a width of at least <NUM>,<NUM> (<NUM> inches).

A first end of compression strap <NUM> is fixedly attached, e.g., stitched, to base <NUM> at an attachment point proximate to a first end of base <NUM>. Compression strap <NUM> extends across and parallel to the base <NUM> by a sufficient distance to, at a minimum, allow compression strap <NUM> to be wrapped around the limb of an average size adult male.

A tourniquet handle <NUM> is provided for tightening tourniquet <NUM>. The tourniquet handle <NUM> is a windlass. In the illustrated embodiments, tourniquet handle <NUM> is generally cylindrical and may include locking grooves <NUM> disposed proximate first and second handle ends. In other embodiments, tourniquet handle <NUM> may be free from locking grooves.

Tourniquet handle <NUM> further includes an aperture through which compression strap <NUM> is threaded. As illustrated in <FIG>, compression strap <NUM> is stitched to itself by a stitch pattern <NUM> to form a strap loop <NUM> which engages tourniquet handle <NUM>. As tourniquet handle <NUM> is tightened, compression strap <NUM> accumulates and forms a twist or knot <NUM> (<FIG>) which creates circumferential pressure. However, when the twist <NUM> is too bulky, tourniquet handle <NUM> has a tendency to fall to one side, thereby limiting the ability to continue to turn and create further circumferential pressure.

The present inventors have determined that the stitch pattern <NUM> impacts the size of twist <NUM>. In keeping with the invention, stitch pattern <NUM> may be triangular where the triangle is generally centered along a width of compression strap <NUM> and the base of the triangle extends transversely along the width of compression strap <NUM> generally parallel to tourniquet handle <NUM> as illustrated in <FIG>. The stitch pattern <NUM> has a maximum widthwise dimension of between ¼ to ½ of the width of compression strap <NUM>. In some embodiments, stitch pattern <NUM> may include various stitch patterns generally centered along the width of compression strap <NUM> including diamond, T, I and V shaped patterns. These patterns are believed to create different size twists but each is believed to markedly reduce the tendency of tourniquet handle <NUM> to fall to one side when it is tightened thereby making it easier to turn the handle and apply additional circumferential pressure.

A cap <NUM> overlays a portion of compression strap <NUM> and is fixedly attached to base <NUM> such that compression strap <NUM> is sandwiched between cap <NUM> and base <NUM>. A handle stop <NUM> and a handle lock <NUM> are attached to cap <NUM> via locking strap <NUM> which is fixedly attached to cap <NUM> at first and second ends. Handle lock <NUM> is optional and may be omitted from all embodiments of the invention.

In accordance with an aspect of the invention, stop <NUM> and handle lock <NUM> are configured to slide freely along locking strap <NUM> between first and second ends. That is, both the lock <NUM> and the stop <NUM> are subject only to minimal friction forces exerted by locking strap <NUM> as they slide along locking strap <NUM>. Neither lock <NUM> nor stop <NUM> are provided with any attachment mechanism to grip locking strap <NUM>. As shown in <FIG>, in one embodiment, handle stop <NUM> is a generally C-shaped member having a strap aperture <NUM>. Locking strap <NUM> passes through strap aperture <NUM>. Strap aperture <NUM> is sufficiently wide that at most only one of the upper boundary and the lower boundary of strap aperture <NUM> contact locking strap <NUM> at any given time thereby allowing handle stop <NUM> to freely slide. Lock <NUM> may comprise a ring, e.g., a triangle ring or a D-ring. Locking strap <NUM> passes through the ring opening thereby allowing lock <NUM> to freely slide.

In use, tourniquet handle <NUM> is twisted to generate a desired amount of torque and inserted into handle stop <NUM> to maintain the desired torque. Handle lock <NUM> may be engaged with one of the grooves formed proximate to an end of tourniquet handle <NUM> to lock tourniquet handle <NUM> in place. However, within about <NUM> minutes after tourniquet application, circumferential pressure loss of up to about <NUM>% may occur due to weave stretch and settling. The present invention provides an advantage in that the user can increase pressure by up to about <NUM>% without removing the tourniquet handle by sliding stop <NUM> and/or stop <NUM> up and away from twist <NUM>. Illustrating this principle, <FIG> depicts tourniquet <NUM> secured in a first position where stop <NUM> is proximate to twist <NUM> and <FIG> illustrates tourniquet <NUM> secured in a second position where stop <NUM> has been slid away from twist <NUM>.

In some embodiments, base <NUM> is substantially rigid and therefore maintains its integrity as tourniquet handle <NUM> is twisted. By substantially rigid, it is meant that base <NUM> is sufficiently rigid to avoid binding or crushing when tourniquet handle <NUM> is twisted while being flexible enough for use on a limb and facilitating tourniquet carriage and storage. In a particular embodiment, base <NUM> is made of a <NUM>"×8½" section of central webbing member, a <NUM>"×8½" of looped end Velcro® affixed to the underside of the central webbing member, and a <NUM>"×<NUM>" strip of upper webbing member affixed to the upper side of the central webbing member. <NUM>" equals <NUM>,<NUM>. The central webbing member section may be made of a <NUM> point heavy weight polypropylene material or its equivalent. The upper webbing member may be made of nylon scuba webbing or its equivalent but each can be made of any other suitable material. For example, upper webbing member may be made of a plastic material. A nonskid or non-slip fabric or any other suitable material may be substituted for the looped end Velcro®.

The separate sections can be joined or combined by sewing, bonding or by using any suitable means. In the present embodiment, the looped end Velcro® section and the central webbing member are sewn together. The looped end of Velcro® is positioned so the bottommost layer of loop is in contact with the limb when the tourniquet <NUM> is used. Looped end of Velcro® is used in this embodiment to increase friction between the tourniquet <NUM> and the limb and to provide padding between the central webbing member and the tissue of the limb. Looped end of Velcro® also helps protect the skin and soft tissue from pinching and bruising that can be associated with the use of the tourniquet <NUM>. Looped end of Velcro® also helps the user in applying tourniquet article <NUM> by holding the tourniquet in place and allowing the user to apply article <NUM> with one hand.

The upper webbing member may be attached to the upper facing side of the central webbing member about <NUM>" in distance from the end of the upper webbing member and positioned beneath the handle <NUM>. In some embodiments, nylon scuba webbing may be used for the upper webbing member to increase the rigidity of the base <NUM> and to minimize binding or crushing of base <NUM> when handle <NUM> is twisted or turned. In other embodiments, multiple sections of scuba webbing can be combined to form the upper webbing member, and this can further facilitate the needs of rigidity while still being flexible enough for use with a limb in addition to making tourniquet <NUM> easier to store and carry. The loop end Velcro® member, central webbing member and upper webbing member may each be constructed of scuba webbing and, each member of base <NUM> can be lengthened, shortened, narrowed or widened. Additional padding may also be added to base <NUM>, or individually to loop end Velcro member, central webbing member or upper webbing member. One or more adhesive strips may also be used to bond one or more of the members comprising base <NUM>.

The tourniquet <NUM> further includes a strap connecting assembly <NUM> for releasably connecting compression strap <NUM> to itself. Strap connecting assembly <NUM> includes a slider buckle having a frame <NUM> with a self-cinching slide member <NUM> engaged with frame <NUM> and a buckle connector <NUM> attached to base <NUM> and configured to releasably engage frame <NUM>. As depicted in <FIG>, frame <NUM> includes a first aperture <NUM> configured to engage buckle connector <NUM> and a second aperture <NUM>. Second aperture <NUM> is defined by first and second longitudinal sides <NUM> and <NUM> and first and second axial sides <NUM>. In accordance with an aspect of the invention, self-cinching slide member <NUM> comprises a cuff or bar that extends across the second aperture <NUM> is externally mounted to first and second axial sides <NUM>. Second aperture <NUM> is sized to minimize slippage and provide smooth strap take up. In accordance with an embodiment of the invention, second aperture <NUM> measures, for example, ¾" x 1½".

While described above is particular embodiment of base <NUM>, in keeping with the invention, base <NUM> may comprise other structures and materials and need not be substantially rigid.

Self-cinching slide member <NUM> includes a longitudinal center section <NUM> and first and second C-shaped end pieces <NUM>. The first and second axial sides <NUM> fit snuggly within the crescent of the C-shaped end pieces allowing the self-cinching sliding bar to slide along opening in the axial direction. In keeping with the invention, self-cinching slide member <NUM> includes a strip gripping vane <NUM> that extends longitudinally from and protrudes radially along self-cinching member <NUM>.

As shown in <FIG>, compression strap <NUM> is looped over self-cinching slide member <NUM> including over strap gripping vane <NUM> such that by simply pulling compression strap <NUM>, the self-cinching slide member <NUM> slides along frame <NUM> until compression strap <NUM> is pinched between self-cinching slide member <NUM> and one of longitudinal sides <NUM> and <NUM>. While not being bound by theory, it is believed that strap gripping vane <NUM> reduces strap slippage while under tension at angles of <NUM> degrees or less by altering the path of travel of compression strap <NUM>.

In accordance with an aspect of the invention, buckle frame <NUM> and sliding member <NUM> are preferably comprised a material that is significantly more lubricious than metal yet strong enough to withstand forces normally encountered when using tourniquets. In some embodiments, buckle frame <NUM> and sliding member <NUM> comprises a glass fiber reinforced polyamide which can withstand pull tests of up to <NUM>,<NUM> (300lbs).

Strap connector <NUM> comprises a hook member <NUM> and a strap channel base member <NUM> as shown in <FIG>. Hook member <NUM> comprises a cuff having an interior surface. Hook member <NUM> extends from a strap channel base member <NUM> which defines a strap engaging aperture not shown in <FIG>. Strap channel base member <NUM> may have edges and includes a first substantially vertical side from which hook member <NUM> extends and a second side which is slightly curved.

In keeping with the invention, as illustrated in <FIG>, compression strap <NUM> is threaded through buckle connector <NUM> and fixedly connected to base <NUM>. This allows buckle connector <NUM> to slide freely along compression strap <NUM> between the point where compression strap <NUM> is attached to base <NUM> and stitch pattern <NUM>. It is believed that allowing buckle connector <NUM> to freely slide creates a mechanical advantage of up to <NUM>:<NUM> which reduces torque and makes the tourniquet easier to use particularly for users with weak grip strength.

In a further embodiment to any of the embodiments discussed above, the strap connecting assembly <NUM> may be substituted for strap connecting assemblies described in <CIT> or <CIT> or for any similar such assembly. In addition, any windlass handle having a central aperture may be substituted for windlass handle <NUM>.

Although particular materials have been identified for particular components and structural elements, one of ordinary skill in the art will appreciate that other materials may be substituted without departing from the scope of the invention. In at least one embodiment, slider buckle, the slide member and the buckle connector may comprise metal or plastic.

It will be further understood that the root terms "include" and/or "have", when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of all means plus function elements in the claims below are intended to include any structure, or material, for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope of the invention.

Claim 1:
A tourniquet (<NUM>), comprising:
a base (<NUM>) including at least first and second sections and having a cap (<NUM>) attached to one of the first and second sections;
a compression strap (<NUM>) attached to said base (<NUM>) and extending across said base (<NUM>), a portion of said compression strap (<NUM>) being sandwiched between said base (<NUM>) and the cap (<NUM>);
a windlass handle (<NUM>) having an aperture, said compression strap (<NUM>) being threaded through said aperture and stitched to itself by a stitch pattern (<NUM>) so as to form a strap loop (<NUM>);
a locking strap (<NUM>) extending across and attached to said cap (<NUM>);
a handle stop (<NUM>) engaging said locking strap (<NUM>) such that (<NUM>) said handle stop (<NUM>) freely slides along said handle strap (<NUM>); and
a strap connector assembly (<NUM>) including a buckle frame (<NUM>) and a self-cinching sliding arm (<NUM>) transversely extending from a first side of the buckle frame (<NUM>) to a second opposing side of the buckle frame (<NUM>), the self-cinching sliding arm (<NUM>) being configured to slide along the buckle frame (<NUM>), said compression strap (<NUM>) being threaded through said buckle frame (<NUM>), and a buckle connector (<NUM>) attached to said compression strap (<NUM>) configured to engage said buckle frame (<NUM>),
wherein the said compression strap (<NUM>) has a first width and said stitch pattern (<NUM>) is centered about a center of the first width,
characterized in that
the stitch pattern (<NUM>) has a maximum widthwise dimension that is between ½ to ¼ of the first width of said compression strap (<NUM>).