Abstract:
The tourniquet is a lightweight, compact, and highly efficient device that can be used to assist in the control of life threatening extremity hemorrhage. The tourniquet utilizes a ratchet mechanism to obtain a mechanical advantage when tightening the tourniquet. A ratchet assembly is located a distance away from a strap end of the tourniquet and overlays a contiguous portion of the strap, allowing the tourniquet to be tightened while minimizing pinch, and further includes an elongated ratchet lever for ease of use, requiring minimal, if any, fine motor skills. The design also includes an indicator region for assistance in use of the device and a sealed and tapered strap-end with indicator for efficient use.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to tourniquets and tourniquets that may be quickly deployed and tightened with a ratchet mechanism. 
     2. Background Information 
     Uncontrolled hemorrhage from an extremity is one of the leading causes of death in military combat and a significant problem in the civilian pre-hospital environment. This uncontrolled hemorrhage from an extremity is a preventable cause of death. 
     US Army research (Calkins et al, “Evaluation of possible battlefield tourniquet systems for the far-forward setting”, Military Medicine Vol. 165, 5:379, May 2000) defines the need for a light, compact, yet rugged tourniquet for far-forward battlefield use. Exsanguination can be reduced through the use of tourniquet technology if properly designed and implemented. The ratchet tourniquet design was deemed superior in performance, but lacked characteristics that allowed the tourniquet to have optimal effectiveness. The key features required for optimal performance of a tourniquet include: easy and quick placement, compact for storage and carrying by a soldier, simplicity of design, ruggedness, and ability to utilize the tourniquet for all extremities (one-handed use). 
     The increased use of battlefield tourniquets in the recent Iraq/Afghanistan wars has led to increasing acceptance of tourniquet use in the civilian pre-hospital setting. This acceptance is based on scientific research that has shown tourniquets to be useful and dispels previously held misconceptions about tourniquets (Kragh et al, “Practical use of emergency tourniquets to stop bleeding in major limb trauma”, J Trauma, 2008; 64:S38-S50). While the prior art has provided examples of features of tourniquets, there is always room for further improvement. 
     SUMMARY OF THE INVENTION 
     The novel design of the present tourniquet overcomes problems encountered with previous tourniquets utilizing a mechanical closure/ratchet device. 
     For a device such as the present field tourniquet for rapid use, a/k/a Rapid Field Tourniquet™ or RFT™, to be successfully utilized in the field or pre-hospital environment, it ideally has several characteristics. 
     1. Simple to operate in all conditions 
     2. Rugged 
     3. Reliable 
     4. Lightweight 
     5. Compact Size 
     6. Able to be applied to self 
     7. Able to be applied one handed 
     8. Able to be applied to trapped extremity 
     9. Require no or minimum fine motor skill 
     10. Provide a means to document application time 
     11. Cost effective 
     Numerous prior art tourniquets exist using various means to control bleeding. This includes mechanical closures, elastics, pneumatic bladders, and loop and windlass. 
     The present invention provides a tourniquet utilizing a strap and mechanical ratchet assembly mechanism to control bleeding from an extremity. This invention addresses the short comings of previous designs utilizing a ratchet mechanism/mechanical closure and strap. 
     In order for a tourniquet to control massive bleeding from an extremity it must exert enough circumferential pressure to occlude arterial blood flow. There are many means by which this is possible. The Rapid Field Tourniquet (RFT) uses a 2 stage process to achieve the required force to stop the bleeding. 
     The first stage is accomplished by tightening the strap around the limb. This will exert some degree of compression on the underlying tissue and blood vessels. This first stage also prepares the Rapid Field Tourniquet (RFT) for the second stage of compression which utilizes a ratchet mechanism. 
     The second stage utilizes a ratchet for mechanical advantage to achieve the required compression to help control bleeding from the extremity. 
     Prior art utilizing a ratchet or other means of mechanical closure place the ratchet or mechanical closure at the end of the strap. When the ratchet or mechanical closure is engaged, the device at the end of the strap becomes the leading edge where constriction occurs. In the previous designs this creates numerous problems which make the tourniquet ineffective. This is described in (U.S. Pat. No. 6,746,470 McEwen et al Jun. 8, 2004). 
     The previous designs that utilize the ratchet or mechanical closure system in this manner cause severe pain, pinching, friction between strap and limb, and entanglement of tissue/skin in the ratchet mechanism. The bulk of these tourniquets place the ratchet or mechanical closure in the traditional location at the end of the strap. Unfortunately placing the ratchet in the traditional position creates problems and is not effective. 
     The Rapid Field Tourniquet&#39;s design departs from typical devices. The Rapid Field Tourniquet utilizes a ratchet/mechanical closure placed on top of the strap and away from the leading edge of the strap, and utilizes an enlarged lever and other features for improved use. 
     This design overcomes several problems encountered as described in (U.S. Pat. No. 6,746,470 McEwen et al Jun. 8, 2004). By placing the ratchet mechanism/mechanical closure on top of the strap (overlaying the strap) and away from the ends the following problems are minimized or overcome: 
     1. No or minimal pinching occurs at the leading edge because the ratchet/mechanical closure is not at the end of the strap. 
     2. The ratchet/mechanical closure sits on top of a wide strap. This prevents or minimizes tissue/skin from becoming entangled in the ratchet/mechanical closure. 
     3. The ratchet/mechanical closure sits on top of a wide strap. This prevents or minimizes friction from occurring between the closure mechanism and underlying tissue/skin. 
     4. The ratchet/mechanical closure sits on top of a wide strap. This creates a simple and efficient system to rapidly apply the tourniquet with only gross motor skills and one handed if needed. 
     The present invention is directed toward a tourniquet using the above design together with having readily assessable features such as an extended ratchet lever for ease of use in stressful situations. The extended ratchet lever is broadened for improved grasping or hooking with a single thumb or forefinger or the side of a hand or glove. A further aspect of the invention includes use of an indicator placed on the extended ratchet lever. The indicator includes a color that is in contrast to the ratchet lever and that is also in contrast to the general color of the tourniquet. A further aspect includes the tapering and sealing of a distal end of the tourniquet strap. Such tapering and sealing accommodates for efficient handling and re-threading of the strap in an emergency situation. The tapered and sealed distal end is especially useful in cases where the tourniquet must be unthreaded and subsequently fed under or about an entrapped limb for wrapping around the limb (as opposed to where the tourniquet is simply placed over the end of the limb already looped through the buckle, such as sliding the tourniquet over the extremity of the injured limb). Further, the tapered and sealed distal end may also include an indicator. 
     The above summary of the present invention is not intended to describe each illustrated embodiment, aspect, or every implementation of the present invention. The figures and detailed description that follow more particularly exemplify these and other embodiments and further aspects of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention may be more completely understood in consideration of the following description of various embodiments of the invention in connection with the accompanying drawings, in which: 
         FIG. 1  is a perspective view of a tourniquet embodying the present invention. 
         FIG. 2  is a side perspective view of the tourniquet shown in  FIG. 1  where the tourniquet is wrapped for transport or storage. 
         FIG. 3  is a front end perspective view of the tourniquet of  FIG. 2 . 
         FIG. 4  is a side view of the tourniquet of  FIG. 1  in an unwrapped position. 
         FIG. 5  is a perspective view of the tourniquet of  FIG. 4 . 
         FIG. 6A  is a perspective view of a portion of the ratchet assembly separate from the tourniquet. 
         FIG. 6B  is a perspective view of a portion of the ratchet assembly separate from the tourniquet and with a portion of the ratchet strip retracted. 
         FIG. 6C  is a side view of a ratchet feature of the present invention. 
         FIG. 7  is a perspective view of a tourniquet embodying the present invention. 
         FIG. 8  is a perspective view of a prior art ratchet used in earlier designs. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A specific embodiment illustrated is not intended to be exhaustive or to limit the invention to the precise form disclosed. It is chosen and described in order to explain the principles of the invention and its application and practical use, and thereby enable others skilled in the art to utilize the invention. 
     The preferred embodiment is an improvement of the traditional ratchet tourniquet used to stop exsanguination from the extremities. Most currently used ratchet tourniquets have the ratchet assembly located at the end of the strap. In the preferred embodiment of the invention, the ratchet assembly is located a distance away from the strap end and overlays a contiguous portion of the strap, allowing the tourniquet to be tightened without the pinch point inherent in most current designs, and further includes an elongated ratchet lever. 
     Referring to  FIGS. 1 and 7 , the tourniquet device of this invention as illustrated in the various embodiments herein is generally designated as  20 . The invention has a strap  30 , with a proximal end  32  and a distal end  34 . The proximal end  34  of the strap  30  is attached to the buckle, generally designated as  40 . At the distal end  34  of strap  30  is a sealed and tapered polymeric end  36  which allows for ease of use in threading buckle  40 . The ratchet assembly, generally designated as  50 , is attached to strap  30  some distance from the buckle attachment of proximal end  32  of strap  30 . At the proximal attachment point for ratchet assembly  50 , on strap  30 , is a time indicator label, designated as  60  and labeled with the notation “TIME” on which a time of use can be written. At the distal attachment point for ratchet assembly  50  on strap  30  is a retainer wrap  70 . For illustrative purposes  FIG. 1  shows strap  30  wrapped back under itself such that tapered end  36  is projecting in the same general direction as is lever  52 .  FIG. 7  also shows strap  30  wrapped back or folded under itself such that tapered end  34  is projecting in a direction opposite lever  52 . 
     Referring to  FIGS. 2 and 3 , when not in use, tourniquet  20  is wrapped with retainer wrap  70  for compact and easy storage. 
     Referring to  FIGS. 4 and 5 , when an injured extremity is able to be accessed without having to un-loop distal end  34  of strap  30  from buckle  40 , tourniquet  20  can commence the first stage of tightening strap  30  around the limb without the buckle looping preparation step. It may be appreciated that tourniquet  20  may be placed around a limb where constricting loop  22  surrounds the limb. A user may then pull distal end  34  of strap  30  for the first stage of tightening. The design allows tourniquet  20  to be utilized even if the injured limb cannot be accessed at the end of the extremity by slipping the constricting loop over the extremity. Where a limb is entrapped the device must be un-looped since there is no access over the end of the limb. By un-looping strap  30  from buckle  40 , tourniquet  20 , or at least one end of strap  30 , can slide under the extremity and be re-looped before the first stage of tightening strap  30  against the limb. The sealed and tapered polymeric end  36  of distal end  34  of strap  30  allows for a semi-rigid end to be fed under the injured extremity, and such action may occur with one hand. Since distal end  34  is tapered and treated with a polymer material, it may be more easily threaded within buckle  40 . Preferably the polymer material is also an indicator and having a color in contrast with the remaining color of strap  30 . Preferably the indicator color is yellow. Colors or shades of red or pink should be avoided since the same would have a lesser effect in these situations where blood present. An indicator placed at the end of distal end  34  allows a user to more swiftly locate the end of strap  30  for faster insertion of strap within buckle  40 . 
     Referring to  FIGS. 6A ,  6 B, and  6 C, ratchet assembly  50  shows a ratchet  51  having a lever  52  configured with a ratchet base  54  which receives a ratchet strip  58  having a series of gears  59 . Lever  52  is depicted in a generally resting position. When lever  52  is lifted in the direction of Arrow A, ratchet strip  58  is ratcheted through ratchet  51  in the direction of Arrow B as is commonly understood. Release tab  55  allows a user to release the mechanism so that the strip  58  may travel in the direction opposite arrow B. Lever  52  is enlarged such that it reduces the need for fine motor skills to operate. With reference to  FIG. 4 , ratchet strip  58  overlays a contiguous portion  61  of strap  30 . It may be appreciated that strap  30  may form a constricting loop  22  even where strip  58  is removed from ratchet  51 . 
     In one aspect, ratchet base  54  includes a base extension  54 ′. Ratchet  51  may be secured to strap  30  in many ways. In one aspect ratchet  51  is secured to strap  30  by using a fastener, such as a rivet that may be inserted through base extension  54 ′ (See  FIG. 6   b ). It may be appreciated that a single fastener, such as a rivet or other fastener may be used to secure ratchet  51  to strap  30 . Ratchet strip  58  is also connected to strap  30 . In one aspect strip  58  is connected by using a fastener, such as a rivet  63  that may be inserted through strip  58  and into strip  30 . It may be appreciated that other types of fasteners may be used for such connection. 
     Lever  52  extends past base terminal end  56 . In one aspect lever  52  has a length L′ that is greater than a length L″ of ratchet base  54 . Lever  52  extends a length L″′ past base terminal end  56 . Preferably lever  52  extends past shoulder  57  such that a user may position more than one finger upon an underside  52 ′ of lever  52  when lever  52  is generally in a resting position. Preferably a user will be able to apply more than one finger to underside  52 ′ when lever  52  is generally in a resting position as shown in  FIG. 6   c . More preferably a user will also be able to apply the side of the hand or palm to the underside  52 ′ of lever  52 . In one aspect lever  52  extends past shoulder  57  at least ½ inch, and preferably greater than ¾ inch. In one aspect terminal end  56  may extend past shoulder  57  ½ inch. When lifted, lever  52  may receive two or more fingers, or the side of a hand or palm, so that an operator may grasp or push securely upon lever  52  and impart a strong tightening or ratcheting force. 
     Lever  52  also has a colored indicator  53  that improves the ease of identification and use in stressful or emergency medical situations. In designs of the prior art, for instance the prior art device  120  shown in  FIG. 8 , where a lever  152  was not enlarged and/or where no indicator was present, a user, especially under stress, may tend to be confused as to which side of the ratchet  151  was the side to lift for operation. The prior art ratchet assembly shown in  FIG. 8  has been used in conjunction with a ratchet strip  158  which overlays a contiguous portion of a tourniquet strap. In some designs, where a string or small pulling cord may be present, the situation was also troublesome since use of a cord is a disadvantage since a string or cord must be grasped with fingers (typically index finger and thumb), an action requiring grip and dexterity. The same is true with a twisting stick/windlass, or turning a dial as in other designs. Further, in some stressful situations, grasping a string or even a small-profiled lever is troublesome. Often a user will be wearing gloves, or will have cold fingers or other circumstances making operations difficult. The present invention, however, which utilizes an enlarged lever and which has a clear indicator  53 , and which may be manipulated with multiple fingers or the side or palm of the hand (or glove), provides for ease and a more rapid application. The device may be applied by a single person and may be applied by one&#39;s self. Lever  52  is operable with gross motor skills, and adjusts ratchet strip  58  having gears  59 , to increase or decrease tension on the strap  30 . The present design is also preferred over devices that use a string for pulling. Use of a string is counterproductive as it suggests to the user that the string should be pulled as opposed to an easier more efficient lifting of the lever of the present invention by use of multiple fingers or with the side of the hand or palm. Placing the indicator  53  on the lever, such as by painting or having a contrasting tip or end, informs the user that such end is the operations end of the lever that is to be lifted for the ratcheting operation. Indicator may also be of a glow-in-the dark variety. 
     A time indicator label  60  incorporated with the tourniquet is important since the label serves as a reminder to mark the time of application. If a tourniquet device is applied for greater than two hours, further medical complication may arise. In addition to operating as a reminder, label  60  provides a space for a user to actually record the time of day of the application. Recording such information is crucial in stressful situations where reference to time can be challenging or where individuals may enter into or out of consciousness or where assistants may come-and-go or may be distracted. 
     Tourniquet  20  is simple to operate in all conditions. Tourniquet  20  is designed to be operated in any environmental condition, day or night. Because a tourniquet may be utilized under combat conditions it might not be possible to operate the tourniquet visually. Large and tactile components such as lever  52  allow easy identification even without visual clues. Tourniquet  20  is easy to use under very stressful conditions, particularly where fine motor skills are impaired and only gross motor skill can be reliable. 
     Lever  52  has a distinct tactile feel. Lever  52  is easy to operate with cold fingers or even when wearing large bulky gloves. It also has indicator  53  with color coding to aid when visual cues may be utilized. 
     Distal end  34 , and particularly tapered end  36  is made with a unique process to apply a polymer to the end of strap  30  which passes through buckle  40  on first stage tightening. This polymer application allows strap  30  to be a single thickness yet provide some degree of firmness to facilitate passage of tapered end  36  when utilized on an entrapped limb or self-application. This polymer is also color coded to add identification if visual cues are able to be used. If vision is not able to be used the polymer application to the tapered end  36  has a distinct tactile feel that aids in use. 
     The simple design combined with rugged components allows tourniquet  20  to survive the rigors of field use. The design and components of tourniquet  20  allow it to be carried in the field and also remain usable after prolonged storage. Designs that utilize compression bladders, elastic, or complicated mechanisms are prone to failure in the field environment and after prolonged storage. 
     Tourniquet  20  is very reliable due to the simple and rugged design. Ratchet assembly  50  is able to operate even when covered in blood, snow, dirt or sand. The large controls aid in operation under stressful conditions. 
     The simple design and components allow tourniquet  20  to be applied to one&#39;s self easily. There are no complex motions or components. Tourniquet  20  may be applied using only a single hand. This is critical if tourniquet  20  must be applied to one&#39;s self on an upper extremity. 
     Often a tourniquet must be applied to a limb that is entrapped or under an object. This entrapment prevents a closed loop type system from being placed on the limb. Tourniquet  20  is easily opened to allow strap  30  to be placed around an entrapped limb and then secured and tightened. As shown in  FIG. 4  strap  30  may be fed through buckle  40 . Strap  30  may also be removed from buckle  40  so that it may be slid underneath a trapped limb (i.e., leg) and then rethreaded once strap  30  encircles the limb. The specially tapered and sealed distal end  36  accommodates this use and threading. The polymer accommodates a low profile for efficient threading. 
     Prior to application of a tourniquet an operator preferably obtains specific training in the indications and proper application of a tourniquet. Tourniquet  20  should be carried in a location that is readily accessible to either hand of a user in an emergent situation. Prior to application of tourniquet  20  preferably all clothing and other material should be removed from the affected area. Tourniquet  20  should be placed around the injured limb. This is accomplished by placing the limb through loop  22  which is generally made of a strap of about 1.5 inch webbing (such as nylon webbing). Or, if the limb is entrapped the 1.5 inch webbing is removed from the 1.5 inch tension buckle  40 , placed around the limb and rethread through the buckle  40 . Different widths and lengths of webbing (strap  30 ) may be used. 
     Once tourniquet  20  is on the limb and placed above/proximal to the injury site, it should be tightened. This is done by pulling on the webbing (the tapered end tip is color coated polymer) which will pull the webbing (strap  30 ) through the buckle  40  and tighten around the limb. It is important to pull strap  30  as tight as possible. This will provided the first stage of compression and prepare the further tightening by the ratchet assembly  50 . 
     Once strap  30  is tight ratchet assembly  50  may be utilized. Ratchet  51  having lever  52  as described above allows for the side of a hand or multiple fingers to grasp and lift lever  52 . This lifting of lever  52  in an arch like manner will incrementally tighten strap  30  by drawing ratchet strip  58  through ratchet  51 . This will effectively shorten the length of strap  30  and increase the circumferential pressure resulting in control of the bleeding. 
     Ratchet assembly  50  should be tightened until control of the bleeding has occurred. Once tourniquet  20  is tight the retainer wrap  70 , such as velcro tabs, may be secured over lever  52  for added security. Once tourniquet  20  is applied the time of application should be documented on time tag  60 . 
     Tourniquet  20  should not be covered once applied. The injured limb and tourniquet  20  should be re-assessed at regular intervals. A higher level of medical care should be sought immediately. 
     Tourniquet  20  may be removed or released by lifting release tab  55  and allowing ratchet strip  58  to retract which in turn loosens strap  30 . Ratchet assembly  50  can then be reset by depressing release tab  55  and then reapplied as needed as described above. 
     While a specific embodiment of the invention will be shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles. It is to be understood that the invention is not to be limited to the details herein given but may be modified within the scope of the appended claims.