WO2005076733A2

WO2005076733A2 - Dual-operation blood sampling device

Info

Publication number: WO2005076733A2
Application number: PCT/IL2005/000171
Authority: WO
Inventors: Uri Carmi
Original assignee: Uri Carmi
Priority date: 2004-02-17
Filing date: 2005-02-10
Publication date: 2005-08-25
Also published as: WO2005076733A3

Abstract

A blood sampling device allowing for the technician to select a syringe-type operation or a vacuum-sealed sampling tube-type operation for drawing blood. The device includes a hollow plunger movably disposed inside a barrel. The barrel has an exterior needle connected thereto. The plunger has an interior needle positioned therein in fluid communication with an air-tight space between the barrel and plunger. Coupling a sampling tube to the interior needle while the exterior needle is in a vein causes drawing and collecting of blood into the sampling tube. Controlled movement of the plunger while the exterior needle is in a vein but prior to coupling of a sampling tube to the interior needle results in drawing of blood into the air-tight space. Blood can thus be drawn from small or weakened veins in a syringe-like manner, eliminating the risk of self-stabbing, and minimizing the risk of vein collapse and hemolysis.

Description

DUAL-OPERATION BLOOD SAMPLING DEVICE

FTELD OF THE INVENTION

The present invention relates to generally to the field of blood sampling devices. More specifically, the present invention relates to a dual-operation device for the collection of multiple blood samples from a vessel.

BACKGROUND OF THE INVENTION

There are two types of blood sampling methods in use today. The first is the more traditional syringe method, which is mainly used for elderly or pediatric patients, patients with chronic illness, or patients undergoing chemotherapy. Veins of such individuals tend to be smaller, injured or difficult to access. For these patients, blood must be drawn using a syringe, since when using a syringe, the amount of vacuum force applied to the vein can be controlled in order to prevent collapse of the vein and hemolysis. Using a syringe also has the advantage that the technician can ascertain whether the vein has been properly accessed when the needle is inserted. Additionally, using a syringe allows for a blood culture to be performed. The risk of using a syringe is, however, that when blood is transferred from the syringe to the sampling tube, the technician can accidentally stab himself. This is of crucial significance, especially when the patient has an infectious disease. In the second method, blood is collected into a plurality of vacuum-sealed sampling tubes via a "Vacutainer" type device, such as that produced by the Becton Dickinson Company. Such a device is illustrated in PRIOR ART Fig. 1. Device 30 includes an evacuated and sealed blood sampling tube 32 into which blood is collected. Tube 32 includes an opening 36 which is sealed by stopper 34. Device 30 also includes a first needle 38 for puncturing the skin and the underlying vein, and a second needle 40 located inside of a housing 42, and covered by a sleeve 48, for facilitating passage of blood to sampling tube 32. A connector 46 provides a continuous blood flow path between first needle 38 and second needle 40. In usage, first the target vein is punctured with needle 38. Then tube 32 is inserted into housing 42 such that second needle 40 pierces through stopper 34 and into tube 32. Due to the vacuum force of tube 32, blood is then drawn to tube 32 via needle 38, connector 46 and needle 40. When the required amount of blood is obtained, tube 32 is removed and re-sealed. Additional tubes are used for obtaining further blood samples. Many Vacutainer type devices are known in the art, for example, U.S. Patent No. 4,409,990 to Mileikowsky entitled "Fluid sampling needle assembly and method of use thereof, and U.S. Patent No. 5,360,01 1 to McCallister, entitled "Blood sample collection." The McCallister reference describes a blood collection system including a plunger having cruciform flanges and a tubular opening extending tlirough the plunger for allowing blood to flow from a syringe to a vacuum-type blood collection tube. A blood tube holder is connected to the upper extremity of the plunger. The blood tube holder is adapted for being secured around a transfer needle that transfers blood from the tubular opening of the plunger to a tube inserted into the blood tube holder and coupled with the transfer needle. The McCallister invention is awkward and inconvenient to use clue to the arrangement of the transfer needle and blood tube holder on the upper extremity of the plunger. When the tube holder is not attached to the plunger, the transfer needle is exposed and thus presents a safety hazard to the technician. When the tube holder is attached, it can be difficult to pull on the plunger in order to draw blood, A further disadvantage is that the McCallister system is relatively large and thus takes up a lot of space when disposed of in a sharps container. Yet another disadvantage is that the transfer needle is long and thus contains "dead space" with air inside so that the first test tube attached to the transfer needle partially fills with air from the transfer needle. The Vacutainer method is highly advantageous for two main reasons. It allows for multiple blood samples to be collected in relatively quick and convenient manner. Fmlhermore, there is also a much smaller risk of the technician stabbing himself when compared to the traditional syringe method. There are many disadvantages to the Vacutainer method, which make it ill- suited for some patients. Firstly, since the technician cannot control the vacuum force applied to the vein, there is a high risk of hemolysis due to the collapse of the vein in patients with small or weakened veins. Also, the technician cannot ascertain whether the needle is indeed inside the vein, since it -is often happens that the needle does penetrate the vein but does not stay inside, and so flashback is seen at the upper tip of the needle but blood does not flow when the vacuum sampling tube is put in. In an opposite case, the vein may be too small so that blood will not flow to the upper tip of the needle to show a flashback, even though the needle is indeed inside the vein. In this case the technician assumes that the needle is not in the vein even though it is. Another disadvantage is that switching of the tubes while the needle is still inside of the vein can cause pain or discomfort to the patient, since it causes the needle to move. Furthermore, the Vacutainer method is not suitable for performing a blood culture. Yet another drawback is that the vacuum sampling tube can sometimes be destroyed due to air penetration. This happens when the teclmician, after inserting the tube, tries to fix the position of the needle in order to place it inside the vein, in cases where the needle has penetrated the skin but not the vein so that there is no blood flow. While trying to fix the position of the needle, the needle often escapes the skin and the tube is filled with air. Thus, each method used for blood sampling has both advantages and disadvantages. Overall, the Vacutainer is more suited for patients with strong and easily accessible veins while a syringe is more suited for elderly, pediatric or chronically ill patients. Yet, it is often difficult to tell into which category a certain patient belongs, until the vein can actually be accessed. It is generally more desirable to use a Vacutainer device, since the risk of self-stabbing is much lower, and since multiple samples can be collected quickly and easily. It would be desirable to provide a blood sampling device which would allow for the technician to select between two modes of operation, a syringe-type operation, or a Vacutainer-type operation. This would depend on the strength of the vein and the risk of hemo lysis, which often can be ascertained by the teclmician only after the vein is punctured with a needle.

SUMMARY OF THE INVENTION

Accordingly, it is a principal object of the present invention to provide a blood sampling device that provides the advantages of both the syringe method and the Vacutainer method, while overcoming the disadvantages of both. In accordance with a preferred embodiment of the present invention, there is provided a dual-operation blood sampling device adapted for enabling the technician to select between a syringe-type operation or a vacuum-sealed sampling tube-type operation for causing the drawing of blood from a vein. In the syringe-type operation, blood is drawn from the vein and into the device due to the vacuum force created by the outward movement of a plunger inside of a barrel. Blood can subsequently be collected from the device and into a plurality of sampling tubes. In the vacuum-sealed sampling tube-type operation, blood is drawn from the vein, through the device, and collected directly into a sealed sampling tube as a result of the vacuum force of the sealed sampling tube that is inserted into the device. Tn a preferred embodiment of the present invention, the device comprises: (a) a circular barrel having an open first end and a second end: (b) a hollow plunger movably disposed within the barrel, the plunger having an upper end and a lower end, the lower end contacting the sides of the barrel so as to form an air-tight space therebetween; (c) an exterior needle for penetrating a vein, the needle being attachable to the second end of the barrel, the needle being positioned such that blood drawn from a vein passes from the exterior needle to the air-tight space (the exterior needle is preferably a standard syringe needle); (d) an interior needle extending through said hollow plunger and having a proximal end and a distal end, the proximal end being covered by a sleeve and the distal end being comiected to the lower end of the plunger, the interior needle being in fluid communication with the air-tight space via an opening in the lower end of the plunger; (e) a vacuum-sealed sampling tube adapted for being inserted into the upper end of the plunger such that the proximal end of the interior needle enters the sampling tube (such sampling tubes are preferably standard evacuated tubes' that are well known);

The device can be used in one of two manners, according to the condition of the vein. In the first mode of operation, the device is used like a syringe. In this case, while the exterior needle is positioned in a vein but prior to coupling of a vacuum- sealed sampling tube to the interior needle, controlled pulling of the plunger results in drawing of blood into the air-tight space. As the plunger is pulled upward, and blood is drawn into the air-tight space, and the air-tight space enlarges. A sampling tube is then inserted into the plunger in order to collect the blood "from behind" after the exterior needle was taken out of the vein. In the second mode of operation, the device is used in a manner similar to a Vacutainer. In this case, coupling the sampling tube to the interior needle while the exterior needle is positioned in a vein results in drawing of blood into the device and collecting the sample into the sampling tube. When it is used as a syringe, the device of the present invention overcomes the primary disadvantage of using a traditional syringe, namely, the relatively high risk of self-stabbing by the teclmician. This is of special significance, since a plethora of methods and devices have been developed in an attempt to overcome this problem, (for example, the Becton Dickinson Vacutainer-Bood transfer device or SARATEDT S-Monovette). A further advantage when the device is used in this manner is that patient discomfort or pain is reduced since the tubes are inserted after the exterior needle is taken out of the vein. When it is used as a Vacutainer-type device, the present invention overcomes the main disadvantage of Vacutainer devices currently employed, that is, the lack of indication that the needle is in the vein. By pulling slightly on the plunger after the needle has been inserted into the vein, the teclmician is given a clear indication of whether the needle is inside the vein. Using the device of the present invention, the teclmician can select, after accessing the vein, the blood sampling method that is to be employed. This way the advantages of both methods can be provided and the disadvantages of both methods can be overcome. There is a reduced overall risk of self-stabbing and hemolysis. Multiple samples can be obtained in separate sampling tubes, regardless of whether the Vacutainer method or the syringe method was chosen. Also, in either mode of operation, a clear indication is provided when needle is inside of the vein, and loss of tubes due to air penetration is reduced. A further advantage of the device of the present invention is that patient discomfort or pain is reduced. Other features and advantages of the' present invention will become more readily apparent and understood from the detailed description section that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention with regard to the embodiments thereof, reference is made to the accompanying drawings, in which like numerals designate corresponding elements or sections throughout and in which: Fig. 1 is a cross-sectional view of a Vacutainer-type device of the prior art; Fig. 2 is an exploded view of a blood sampling device, according to a preferred embodiment of the present invention; and Fig. 3 is a cross-sectional view of a blood sampling device, according to a

preferred embodiment of the present invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Referring now to Figs. 2 and 3, there is shown a preferred embodiment for a blood sampling device 70, constructed and operated in accordance with the principles of the present invention. Blood sampling device 70 includes a hollow plunger 50 that is slidably engaged inside of a barrel 52. Hollow plunger 50 includes a plunger cap 62, preferably formed from rubber, that contacts the sides of barrel 52 so as to form a substantially air-tight barrel space 66 inside of barrel 52. As plunger 50 is moved upward with respect to barrel 52, barrel space 66 is enlarged. A vacuum-sealed sampling tube 54, preferably a standard vacuum sampling tube, is adapted for being inserted inside of hollow plunger 50. Sampling tube 54 comprises an opening 92 and a seal 90 covering opening 92. It will be appreciated that the opening of the plunger is adapted in size for receiving standard size sampling tubes. Device 70 also includes an exterior needle 60, adapted for attachment to barrel 52 via needle attacliment element 72, and an interior needle 56, located inside of plunger 50. Exterior needle 60 is preferably a standard syringe needle, and needle attachment element 72 is a standard attachment element for use with needles or cateters. Interior needle 56 includes a proximal end 74 for piercing and entering sampling tube 54 and a distal end 76 that is connected to plunger cap 62 via a needle holder 64. Needle holder 64 comprises flange members 94 which limit the extent to which sampling tube 54 may be inserted into plunger 50, Flange members 94 may

alternatively be located on the inner side of plunger 50. It will be appreciated that the exterior needle is a standard needle and the sampling tube is a standard evacuated sampling tube, both of which are readily available on the market. The blood sampling device is sized so as to enable usage of the device with such needles and tubes. The proximal end 74 of needle 56 is covered by a sleeve 58 made of rubber or any other suitable material. Sleeve 58 prevents penetration of air to air-tight barrel space 66 while plunger 50 is pulled and also prevents blood from spilling out of airtight space 66into the hollow interior of plunger 50. An opening 86 in plunger cap 62 maintains interior needle 56 in fluid communication with barrel space 66. Hollow plunger 50 is provided with outwardly extending plunger handles 82, 84, for facilitating movement of plunger 50 by the teclmician. Movement of plunger 50 is limited by a first safety element 78 which is located on the lower exterior surface of plunger 50, and which extends circumferentially around plunger 50, and by a second safety element 80, which is located on the upper interior edge of barrel 52, and which extends circumferentially around the inner circumference of barrel 52 (see Fig. 2). When plunger 50 is pulled upward first safety element 78 abuts second safety element 80, thereby preventing further upward movement of plunger 50 and preventing it from being drawn completely out of barrel 52.

Barrel 52 is provided with an angled upper edge 88, which extends only slightly outward with respect to barrel 52. This is in contrast to plunger handles 82, 84, which extend substantially from plunger 50 for facilitating pulling thereof. Angled edge 88 provides the technician with a way to firmly hold the device while blood samples are being taken.

An optional safety component 68 may be provided between barrel 52 and needle attachment element 72. Safety component 68 functions as a one-way flap which allows entry of blood into barrel space 66 when plunger 50 is pulled upward but which prevents flow of blood from barrel space 66 to needle attacliment element 72 and needle 60 if plunger 50 is accidentally pushed downward. The operation of device 70 will now be explained with reference to Figs. 2 and 3. The teclmician first penetrates the skin and pierces a vein of the patient using needle 60. To ascertain that the vein was indeed penetrated, the plunger is pulled back very slightly and gently. If a flash of blood is seen at the end of the needle in air-tight barrel space 66, this is an indication that a vein has been properly reached. The technician now assesses the condition of the vein and decides whether to proceed to draw blood in a syringe-like method or in a Vacutainer-like method. If the vein appeal's to be weakened or small, then there is a risk of collapse if a strong vacuum force is applied. The determination as to whether the vein is weakened can be made by pulling on the plunger. If pulling the plunger strongly yields no blood flow while pulling the plunger slightly produces smooth blood flow, then it can be concluded that the vein is weakened and has a tendency to collapse. In such cases the device teclmician uses the blood sampling device in a manner similar to a conventional syringe. To draw blood from the vein in a manner similar to a syringe, plunger 50 is slowly pulled upward, and blood flows into barrel space 66 through needle 60. As plunger 50 is pulled upward, barrel space 66 enlarges and fills with blood. When the required amount of blood is obtained, needle 60 is removed from the vein and needle 60 is recapped appropriately or disposed of. In some cases, a plug may be placed on the needle attachment element 72. It will be appreciated that in this method, the vacuum force on the vein is controlled by the teclmician as he pulls the plunger. Blood flow can thus be monitored and the risk of vein collapse and hemolysis is relatively minimal. Next, vacuum-sealed sampling tube 54 is inserted into plunger 50 such that the proximal end 74 of needle 56 penetrates sleeve 58 as well as seal 90 and enters into sampling tube 54. The vacuum force of sampling tube 54 causes blood in barrel space 66 to flow through opening 86, tlirough needle 56, and into sampling tube 54. When the required amount of blood is obtained in sampling tube 54, sampling tube 54 is removed, thereby removing the vacuum force such that blood stops flowing upward, Further vacuum-sealed sampling tubes are then employed in the same manner until the necessary number of samples have been collected. In case the technician attempts to expel blood from air-tight space 66 through exterior needle 60 by pushing plunger 50, and exterior needle 60 or needle attacliment element 72 is blocked by a blood clot, then there is a risk that blood will be splashed onto the technician's face. To prevent this, sleeve 58 can optionally be designed to be long enough, such that when tube 54 pushes sleeve 58 towards interior needle 56, sleeve 58 will bend and the hole created on the sleeve will be on the side of sleeve 58 and not on top. This assures that if the teclmician mistakenly uses the device in the manner described above, the blood will splashed towards the side of plunger 50 and not to the teclmician' s face. In the second mode of operation, if, when penetrating the vein, the vein appears to be strong, then the technician proceeds to use device 70 in a Vacutainer- type manner. This means that instead of pulling on the plunger in order to draw blood into barrel space 66, as in the syringe-like method, a vacuum-sealed sampling tube 54 is immediately inserted into plunger 50, so as to couple with needle 56 as described above. The vacuum force of the vacuum-sealed sampling tube causes blood to be drawn from the vein, tlirough exterior needle 60, through opening 86, and through interior needle 56, so as to collect in sampling tube 54. When sampling tube 54 is filled with the needed amount of blood, sampling tube 54 is removed and re-sealed. Sleeve 58 then returns to its original position and additional tubes are used for obtaining further blood samples, as they are required. It will be appreciated that sleeve 58 which protects interior needle 56 returns to its original position whenever a sampling tube 54 which has been filled is removed from plunger 50. Thus, this occurs whether the device is being employed in a syringelike mamier or in a vacuum sampling tube-type manner. In the syringe-type operation, the amount of blood, and thus the number of tubes employed, is limited since the exterior needle has already been removed from the vein. However, in the Vacutainer- type operation, any number of sampling tubes may be filled, one after the next, with blood, with the sleeve 58 returning to its original position each time a sampling tube is filled with blood and removed. Thus, the device of the present invention provides a very significant advantage when compared with devices of the prior art. Namely, it gives the technician the ability to choose, depending on the strength of the vein, the method that is to be employed for drawing blood from the vein. The technician can ascertain whether the vein has been reached and the risk of vein collapse and hemolysis is significantly reduced. Also, by using the device in a syringe-like blood drawing method, the risk of self-stabbing is significantly reduced when compared to regular syringes. This is of special significance, since the medical community has been strictly cautioned against

the use of standard syringes due to the safety aspect. The U.S. Department of Labor Occupational Safety and Health Administration (OSHA) has warned that, "A situation may exist which necessitates tising a syringe to draw blood and transfer the collected blood into a test tube before disposing of the contaminated syringe. In such a situation, a syringe with engineered sharps injury protection must be used. Removal of the safety-engineered needle must be accomplished after activation of the safety feature and using safe work practices (including use of mechanical means of removal whenever possible). Transfer of the blood from the syringe to the test tube must be done using a needle-less blood transfer device." The present invention overcomes the need for extra safety measures employed when using regular syringes, since the device can be used in a syringe-type operation, but without the safety hazard of a conventional syringe. The present invention provides a much safer solution for cases where the patient's veins are weakened or small, and a syringe must be used instead of a Vacutainer, since using a Vacutainer significantly increases the risk of vein collapse and hemolysis. Having described the invention with regard to certain specific embodiments thereof, it is to be understood that the description is not meant as a limitation, as further modifications will now become apparent to those skilled in the art, and it is intended to cover such modifications as fall within the scope of the appended claims.

Claims

Claims:

1. A dual-operation blood sampling device adapted for enabling the teclmician to select between a syringe-type operation or a vacuum sampling tube-type operation for performing drawing of blood from a vein, the device comprising; (a) a circular barrel having an open first end and a second end; (b) a hollow plunger movably disposed within said barrel, said plunger having an upper end and a lower end, said lower end contacting the sides of said barrel so as to form an air-tight space therebetween; (c) an exterior needle for penetrating a vein, said needle being attachable to said second end of said barrel, and being positioned such that blood drawn from a vein passes from said exterior needle to said air-tight space; (d) an interior needle extending within said hollow plunger and having a proximal end and a distal end, said proximal end being covered by a sleeve and said distal end being connected to said lower end of said plunger, and said interior needle being in fluid communication with said air-tight space via an opening in said lower end of said plunger; (e) a vacuum-sealed sampling tube adapted for being inserted into said upper end of said plunger such that the proximal end of said interior needle enters said sampling tube; wherein coupling said vacuum-sealed sampling tube to said interior needle while said exterior needle is positioned in a vein results in drawing and collecting of blood into said sampling tube, and wherein controlled pulling of said plunger while said exterior needle is positioned in a vein but prior to coupling of a vacuum-sealed sampling tube to said interior needle results in drawing of blood into said airtight space.

2. The device of claim 1, wherein said barcel comprises an angled upper edge for facilitating gripping of the device by the technician.

3. The device of claim 1, further comprising a one-way flap positioned at the second end of said barrel for preventing accidental expelling of blood from said air-tight space back out through said exterior needle.

4. The device of claim 1, further comprising a first safety element positioned on said plunger and a second safety element positioned on said barrel, wherein said first and second safety elements are adapted for abutting one another during upward movement of said plunger so as to limit the movement of said plunger within said barrel.

5. The device of claim 1, further comprising a needle holder for securing said interior needle to said plunger.

6. The device of claim 1, wherein the sleeve is formed from rubber.

7. A method for drawing blood from a vessel and for collection into at least one tube, comprising; (a) providing a dual-operation blood sampling device adapted for enabling the technician to select between a syringe-type operation or a vacuum sampling tube-type operation for effecting drawing of blood from a vein, the device comprising;

(i) a circular barrel having an open first end and a second end; (ii) a hollow plunger movably disposed within said barrel, said plunger having an upper end and a lower end, said lower end contacting the sides of said barrel so as to form an air-tight space between said plunger and said barrel; (iii) an exterior needle for penetrating a vein, said needle being attachable to said second end of said barrel; (iv) an interior needle extending through said hollow plunger and having a proximal end and a distal end, said proximal end having a sleeve covering and said distal end being connected to said lower end of said plunger, and said interior needle being in fluid communication with said air-tight space via an opening in said lower end of said plunger; (v) a vacuum-sealed sampling tube adapted for being inserted into said upper end of said plunger such that the proximal end of said interior needle enters said sampling tube;

(b) penetrating a vein using said exterior needle;

(c) pulling gently on the plunger so as to determine that the vein was properly reached; (d) choosing, based on the strength of the vein, whether to continue to draw blood from the vein using a syringe-type method, or alternatively performing drawing of blood using a vacuum sampling tube-type method.

8. The method of claim 7, further comprising the steps of; (a) pulling the plunger upward in a controlled mamier so as to cause blood to be drawn from the vein and into the air-tight space; (b withdrawing the exterior needle from the vein: (c) inserting a vacuum-sealed sampling tube into the plunger such that said proximal end of said interior needle enters inside said tube and such that the vacuum force of said sampling tube causes blood from located in said air-tight space to pass from said air-tight space, through said interior needle, and into said sampling tube, and removing said sampling tube when the required amount of blood is obtained in said tube.

9. The method of claim 8, further comprising repeating step c of claim 8 any appropriate number of times until the blood is said air-tight space is used up.

10. The method of claim 8, further comprising disposing of the exterior needle prior to step c.

11. The method of claim 7, further comprising the step of inserting a vacuum-sealed sampling tube into said plunger such that said proximal end of said interior needle enters inside said tube and such that the vacuum force of said sampling tube causes blood to be drawn from the vein, through the interior needle, and collected directly into said sampling tube, and subsequently removing said sampling tube from said plunger when the required amount of blood is obtained in said tube.

12. The method of claim 11 , further comprising repeating the step of claim 11 any appropriate nmnber of times so as to obtain the required number of samples, and subsequently withdrawing the exterior needle from the vein.