Abstract:
Ergonomic handle for a syringe intended for puncturing blood vessel walls and establishing blood path connections. The typical syringe comprises a tube body and a needle body. The handle prevents unintended displacements between the tube body and the needle body and permits placement of the thumb and forefinger at the side and the tip of the puncture needle for more precision in use.

Description:
TECHNICAL FIELD 
     The invention relates to an ergonomically designed handle for a syringe that includes a tubular body and a needle body which is used to puncture blood vessels and establish blood path connections. 
     BACKGROUND ART 
     In the medical field, it is frequently required to establish a connection between blood vessels (veins and arteries) and injectors or containers of different kinds. The connection must be made with total sterility. Leakage must be avoided as far as possible. Examples of treatments requiring blood vessel contact are blood transfusion inclusive blood giving, blood sampling with the assistance of test containers under negative pressure, and intravenous supply of medicine, nourishment or just liquid for blood volume expansion, commonly called a drip. In all these applications it is essential that the puncture of the vessel wall can be done without damage to the surrounding tissues. Failures are unpleasant, even under the best circumstances, but may cause serious damage as well. 
     A common syringe for insertion in blood vessels of different kinds is shown in FIG.  1 . The syringe consists of a tube body ( 1 ) with a channel that continues in a thin plastic tube ( 3 ). The rear opening of the tube body is designed with a conical widening for attachment to a syringe or a catheter. The opening is at the beginning filled by the hollow needle ( 4 ), which continues with the needle body ( 5 ), the rear part of which has a transparent room, which gets filled with blood, when satisfactory blood vessel contact has been established. Through the channel runs the hollow puncture needle ( 4 ) with a beveled, sharpened tip, which extends a few millimeters in front of the front end of the thin plastic tube. 
     When establishing a blood vessel connection, one chooses a suitable, superficial blood vessel (vein or artery, depending upon type of treatment) and tries to direct the tip of the puncture needle to penetrate the skin just over the chosen blood vessel so that the tip hits the vessel centrally. After penetration of the vessel wall the puncture needle with the plastic tube can be directed axially obliquely into the blood path. When the above mentioned transparent room behind the needle starts filling with blood the needle body with the belonging puncture needle is kept still, while the tube is advanced so that the needle tip no longer is in front of the end of the plastic tube. This is done to prevent the needle tip from hurting the vessel wall, when the plastic tube afterwards is brought forward into the blood path, to the main part of its length, with the aid of the tube body. When the plastic tube has reached the desired position in the blood path, the tube body is kept still. The puncture needle, which, so far, has prevented leakage by its close fit to the inner wall of the plastic tube, is withdrawn with the needle body and the desired connection to the syringe, container or catheter is made. 
     For reasons of sterility the plastic tube must not be touched before or during the insertion into the blood lumen. The distance from the needle tip to the grip around the needle body is long. The grip surfaces are not well defined, especially as the hands most frequently have to be provided with gloves. The insertion demands a number of complicated changes of direction. After the skin penetration there is no visible indication of the position of the needle tip. Moreover, the blood vessels are frequently badly fixed under the skin and have troublesome tendencies to “roll away”. 
     In spite of these, from the ergonomic point of view, very unfavorable circumstances, experienced nurses with daily training become very skilled and seldom fail. The circumstances are different for doctors, nurses, ambulance crews and apprentices, who are infrequently put to the task. Failures will cause the patient discomfort and are embarrassing to the operator. Further, loss of valuable material will arise. 
     Amendment proposals concerning the ergonomics at the establishment of vein and artery connections and similar operations can be found in the German “Offenlegungsschriften” 2306068 and 4244563. The solution of the problem according to the former is applicable to injection needles without a surrounding plastic tube only. While it is true that the latter reference mentions the possibility of combination with a plastic tube, the proposed design causes large risks of damages as no firm connection between the needle body and the tube body exists. As will be explained below unintended displacements between those parts cause serious moments of risk. 
     SUMMARY OF THE INVENTION 
     The invention concerns a handle ( 6 ) for a syringe, the syringe comprising a needle body ( 5 ) with a hollow needle ( 4 ) of suitable material and a tube body ( 1 ) with a thin plastic tube ( 3 ) intended for the puncture of blood vessel walls and the establishment of blood path contact. The handle is designed to admit placement of the thumb and the forefinger at the side of the tip of the needle ( 4 ) and in its proximity and prevents unintended displacements between the needle body ( 5 ) and the tube body ( 1 ) during the puncture phase. 
     In a preferred embodiment of the invention, the grip part ( 7 ) of the handle is designed so other parts of the hand can help the governing of the syringe. Examples of such embodiments of the invention are shown in FIGS. 2 and 3. 
     Further, the handle ( 6 ) should be designed to permit one to easily disengage the tube body, without an essential change of position of the thumb/forefinger grip and without influencing the stable fixation to the needle body. When the tube body has been disengaged, it may by the other hand of the operator be advanced into the lumen to a suitable position without changing the position of the needle body and with it the puncture needle position. The handle may be provided with an indication stick ( 8 ) that shows the position of the tip of the puncture needle and may be of good assistance to operators without daily training. 
     When the tube body ( 3 ) has been advanced to the desired position, the puncture needle ( 4 ) is removed. To prevent blood flow through the tube body&#39;s rear end, which until now has been made tight by the needle body, the operator begins the removal by compressing the skin area above the front end of the plastic tube with his or her other hand. This is done until he or she has withdrawn the puncture needle, let go the handle with the puncture needle and placed the stopper, intended for this purpose, in the rear end of the tube body. Now the operator has both hands free and can fix and flow-test the tube body and separate the needle body ( 5 ) from the handle, which may be taken care of for cleaning, autoclaving and repackaging. 
     The handle grip ( 7 ) must, besides being ergonomically pleasant, provide a comfortable but firm and stable fixation to the needle body ( 5 ), suitably to the shield ( 9 ), and to the tube body ( 1 ), suitably to one of its wings ( 2 ). In this way a sure protection against unintended displacement of the needle tip in relation to the tube end is obtained. The needle tip is very sharp. Undesired displacements of their mutual position may cause the sharpened edges to cut loose plastic fragments from the tube tip. The fragments may get into the blood path. This may have incalculable consequences. 
     When the handle grip has been mounted, the operator may begin a skin and vessel puncture after the usual hygienic preparations. As shown in FIG. 4, the thumb/forefinger grip near the needle tip is ergonomically favorable and permits use of the fine motor movements of the hand. The bigger muscle groups in forearm, upper arm and trunk need normally not take part. The person who so wishes may get guidance at and after the vessel wall penetration by the indication stick ( 8 ), which may be provided on the handle. 
     A handle with the qualities mentioned above may be designed in several different ways. A couple of those different embodiments are shown in FIGS. 2 and 3. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIGS. 1A-B shows two parallel projections, in two perpendicular planes of a so-called VENFLON®-syringe, which is suitable for use with the handle of the invention. VENFLON is a registered trade mark; 
     FIGS. 2A-C shows an embodiment for carrying out the invention; 
     FIGS. 3A-N shows another embodiment for carrying out the invention; and 
     FIG. 4 shows use of the handle with a syringe by an operator. 
     FIGS. 5A-B shows the handle attached to a syringe that does not have a shield. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 2 shows a handle ( 6 ) comprising two straight beams both with an almost uniformly curved section and joined by a border ( 10 ), of a suitable polymer material with springy hinge function, and provided with a snap lock ( 11 ) at the back end. The beams are designed to enclose one wing of the tube body ( 2 ) and fix it with the aid of the snap lock ( 11 ). One of the beams, preferably the one below, is provided with a projecting squeeze arrangement ( 14 ) suitable to be placed over the shield ( 9 ) of the needle body ( 5 ) from the side or from above, at which the rear half of the squeeze arrangement ( 14 ) first meets the back surface of the shield ( 9 ) to prevent tendencies for backward movement of the needle body ( 5 ). In the squeezed position the shield ( 9 ) becomes fixed not just in height and side position but also in a defined direction essentially parallel to the squeeze arrangement ( 14 ). With the preserved thumb/forefinger grip the snap lock ( 11 ) shall allow opening with the little or ring finger, at which the tube body&#39;s wing ( 2 ) is let free and the tube body ( 2 ) may be advanced, while the needle body ( 5 ) still may be controlled and manipulated by the preserved thumb/forefinger grip. As shown in FIG. 5, the handle is attachable to a syringe that does not have a shield. The squeeze arrangement  14  contacts the tube body where the shield would be located. 
     FIG. 3 shows a handle constructed as a hollow hexagonal rod with a function similar to a clothes-pin. The hexagonal rod is, except the piece ( 15 ) of the back wall ( 16 ) which serves as a springy hinge, cut longitudinally through the front wall ( 17 ) and the mentioned back wall ( 16 ). The front part of the rod is cut obliquely to form shanks ( 18 ) of the clothes-pin. The shank angles may preferably be larger at the front ( 17 ) to give a bit larger opening of the rear front wall cut of the rod. The rear part of the front wall ( 17 ) of the rod has a pair of projecting jaws ( 13 ) preferably provided with one or more teeth intended to fix one wing of the tube body firmly. At an upper wall, the rear part of the rod has a squeeze arrangement ( 14 ) suitable for the shield ( 9 ) of the needle body ( 5 ). This is in relation to the longitudinal cut. The rear half of this squeeze arrangement ( 14 ) is made to contact the rear wall of the shield ( 9 ) to prevent the tendency of the needle body ( 5 ) to move backwards in relation to the tube body ( 1 ). The squeeze arrangement ( 14 ) is designed to give a firm fixation of the shield ( 9 ) in the desired needle direction and height and side. 
     The design provides that one, with an unchanged thumb/forefinger grip, first can securely direct the skin and blood vessel puncture and after that can open the clothes-pin to let the tube body wing ( 2 ) free. They may then with ease advance the tube body ( 2 ), while the needle body ( 5 ) is still fixed in the handle in an unchanged position, until the needle body ( 5 ) can finally be withdrawn and the rear end of the tube body ( 1 ) made tight by the stopper that until now has been sitting at the rear end of the needle body. 
     The figure shows the possibility of attaching the earlier mentioned indicating stick ( 8 ) to show the position of the needle tip and profiles with the object first to prevent the gloves of the operator from contaminating the plastic tube or the needle tip and second to reinforce the shanks of the clothes-pin. In the example, a hexagonal rod has been chosen and this is, from the grip point of view, the preferred design. However, other polygonal and circular crosscuts are just as useful even if less grip-friendly. 
     A handle according to the invention may be designed as a single-use item. Then nothing prevents designing the handle as permanently bound to the needle body ( 5 ) and temporarily bound to and easily disengaged from the tube body ( 1 ). As the invention primarily is intended as expedient to operators that due to deficient training otherwise may have difficulties performing blood vessel punctures in the correct way, designing as a separate attachment and article for repeated use is preferred. 
     As shown in FIG. 3, attaching the handle for repeated use to a syringe is done as follows: The rear half of the squeeze arrangement ( 14 ) is brought into contact with the back side of the shield ( 9 ) and to prevent backward movements of the puncture needle ( 4 ) in relation to the plastic tube ( 3 ). After that, the jaws ( 13 ), intended to enclose one wing ( 2 ) of the tube body, are opened by pressing together the shanks ( 18 ). The wing is brought into the gap between the jaws ( 13 ) and fixed there by letting go of the pressure on the shanks ( 18 ). During the entire procedure the rear half of the squeeze arrangement ( 14 ) rests against the back side of the shield ( 9 ). After the fixation of the tube body&#39;s wing ( 2 ), the handle is turned around an axis, which is roughly parallel to the axis of the syringe and runs through the joint of the wing ( 2 ), until one reaches the desired grip position while the squeeze arrangement ( 14 ) is brought to its final position at the needle body ( 5 ) and fixed there. Mounting the handle as shown in FIG.  2  and variants of the exemplified handles are done in the same way as far as applicable.