WO1992004867A1

WO1992004867A1 - A blood sampling device

Info

Publication number: WO1992004867A1
Application number: PCT/SE1991/000617
Authority: WO
Inventors: Anders Trell; Erik Trell; Sven Gustafsson
Original assignee: Anders Trell
Priority date: 1990-09-17
Filing date: 1991-09-16
Publication date: 1992-04-02
Also published as: SE9002960L; SE9002960D0; SE467442B

Abstract

The present invention relates to a blood sampling sleeve which is intended for coaction with a blood sampling tube in which an internal subpressure prevails and which is sealed at one end thereof against the ingress of air and liquid by means of a sealing device that can be pierced or penetrated by a needle. The sampling sleeve is a one-piece structure intended for one-time-use only. The sleeve is also patient-friendly and is risk-free to the user, and can be handled quickly and easily. The sleeve includes an inner needle (16) which is intended to pierce the sealing device (14) fitted to the sampling tube (12), and an outer, conical standardized connector (22) which is intended for connection to a standard vein-puncturing needle. An inner channel (20) connects the connector orifice with the needle orifice and an inner valve (26) is provided in the channel (20). The valve (26) is closed when in a non-activated state and is intended to be opened automatically by the sealing device (14) of the sampling tube when the sealing device is penetrated by the needle (16).

Description

A Blood Sampling Device

Technical Field

The present invention relates to a blood sampling sleeve intended for coaction with a sampling tube in which a subpressure prevails and which is sealed in an airtight and liquid-tight fashion by a sealing device which is capable of being penetrated or pierced by a needle. The sampling sleeve is a one-piece structure intended for one-time-use only, i.e. a so-called disposable sleeve. The sleeve is also friendly to the patient, risk-free to the user and can be manipulated quickly and easily.

Background Art

Various types of devices for collecting blood samples in one or more containers, by inserting a needle into a vein of a patient are known to the art. Sampling of blood is a standard procedure which is carried out on a very large scale and which places particular demands on the instruments used. The instruments, or equipment, used must be both simple and inexpensive and capable of being handled effectively and simply. Furthermore, present-day instruments of this kind must be capable of enabling samples of body fluid, such as blood, to be taken without the risk of contaminating the personnel concerned.

Samples are generally taken effectively by collecting blood in separate, evacuated vacuum sampling tubes which are sealed against the ingress of air and liquid by means of an appropriate sealing device, such as a rubber stopper. The vacuum sampling tube is used together with a cylindrical sampling sleeve, which is open at one end thereof and provided with a throughpassing, double- pointed needle at the other end thereof.

The outer needle point is inserted into a patient's vein and the vacuum sampling tube then pushed into the cyl¬ indrical sample sleeve, so that the inner needle point will penetrate or pierce the rubber stopper fitted to the tube. The subpressure prevailing in the sampling tube causes blood to flow through the open passage of the hollow needle and into the tube. The subpressure in the sampling tube may also be generated by fitting a sealing plunger to the other end of the tube and by drawing the plunger out towards the opposite end of the tube, when taking a sample.

An instrument of this kind intended for one-time-use only is described and illustrated in US-A-3,520,292. The sleeve is provided with a two-directional needle, wherein the inner needle is protected against contamina¬ tion by a displaceable seal provided at the opposite end of the sleeve, this seal accompanying the rubber stopper when moving the sampling tube axially in the sleeve. The outer part of the needle is protected against con- tamination by a removeable protective cap, which is removed from the needle prior to inserting the needle into the patient's vein.

A similar disposable instrument intended for veterinary use is described and illustrated in EP-A-0026679. This instrument is delivered as a complete sampling instru¬ ment with the needle and vacuum tube mutually assembled.

US-A-4,326,541 and SE-B-425943 describe different exam- pies of how valves are formed in known sampling instruments. The valve taught by US-A-4,326,541 func- tions to close the connection or passageway between the outer and the inner needle when the valve is in its normal, closed position, and opens the passageway from the patient to the sampling tube in response to exter- nal, manual activation. SE-B-425943 teaches an automa¬ tic non-return valve, which is disposed between the outer and the inner needle, and a resilient and self- sealing protective sleeve which surrounds the inner needle. The protective sleeve is pierced by the needle when the sampling tube is pushed into the sleeve, and springs back to its original position when the sampling tube is removed for replacement with a fresh tube, so as to stop the flow of blood through the needle. The instrument is also provided with indicator means which indicates the successful puncturing of a vein, when blood flows into the instrument.

The aforedescribed sampling instruments are encumbered with a number of drawbacks and none of these known instruments fulfils the particular demands that can be placed on instruments of this kind. A sleeve intended for repeated use and provided with a double-pointed disposable needle, possibly contaminated, is moved from patient to patient, which is both unhygienic and risky. Since the sleeve in this case can be used repeatedly, it must be extremely well constructed and dimensioned, conditions which render the instrument expensive. The double-pointed needle cannot be handled easily by the personnel concerned, who are more accustomed to handling single-pointed needles in other contexts. The risk of injury when changing needles is high, particularly since the inner needle may have been contaminated by a previ¬ ous sample. Such needle changes thus place the person¬ nel concerned at risk, a circumstance which should be avoided. Blood sampling often requires more than one sampling ^■tube -to be filled, which involves an exchange of sam¬ pling tubes when only one vein puncture is made in the patient concerned. When the needle is left in the vein, a tube change unavoidably results in the spillage of blood, unless protective measures are taken. In order to take care of blood spillage, the inner needle is often surrounded by an elastic casing which is pierced by the needle together with the rubber stopper fitted to the sampling tube, as taught by SE-B-425943. When a sampling tube is changed, the blood spillage is collect¬ ed in the elastic casing and is also deposited on the enclosed needle point. This blood spillage fastens to the rubber stopper on the next sampling tube, therewith creating hygiene problems for the nursing personnel concerned. As before described, it is known to provide internal valves for the purpose of stopping the flow of blood when changing from one sampling tube to another. The provision of such valves with conventional double- pointed needles, however, is both complicated and expen¬ sive and consequently not suited for instruments that are intended for one-time-use only.

Blood sampling procedures are often accompanied by the need for subsequent intravenous treatment of the patient, which when using known conventional sampling instruments necessitates further insertion into the vein of the patient, which can at times be troublesome and painful. Because the known sampling instruments require more expensive, double-pointed needles for sampling purposes, the less expensive, sterile vein-needle type of instrument normally used for puncturing a vein cannot be used in this connection. This precludes the possi¬ bility of choosing between different needle dimensions

in accordance with the particular conditions of a patient when sampling with known instruments.

Disclosure of the Inventive Concept

An object of the present invention is to solve the aforesaid problems by providing a disposable sampling sleeve which is friendly to the patient and which can be handled safely and easily by the user. The inventive sampling sleeve is comprised of one or a few simple components, all of which can be produced from readily machined materials of low kilo price.

According to the present invention, a sampling sleeve of the kind described in the introduction is characterized in that it includes an inner needle which is intended to pierce the sampling-tube sealing device, and an outer, conical, standardized connector intended for connection to a standard vein-puncturing needle. The connector orifice is connected with the needle orifice by an internal channel having arranged therein an internal valve which is closed when in an inactivated position and which is intended to be opened automatically by the tube sealing device when said device is pierced by the needle.

Further advantageous characteristics of the invention will be evident from the following description and from the dependent Claims.

The external, standardized connector is formed inte¬ grally with the sampling sleeve and enables the use of needles selected from a conventional assortment of needles for sampling purposes. Since the cost of such needles only constitutes a fraction of the cost of the double-pointed needles, this solution affords a considerable reduction in the sampling cost for each patient treated. The use of the simpler form of needles also results in a considerable simplification and there¬ with in more rapid handling of the sampling instrument, which also contributes towards a reduction in cost.

When it is necessary to subject the patient to intra¬ venous treatment after taking a sample of the patient's body fluid, the same insertion and standard needle as that used to take the sample can be used in said subsequent treatment, thereby relieving the patient of painful, repeated puncturing of the vein and also providing for quicker and more effective handling of the treatment. The possibility of using a standard needle assortment also enables needles of different dimensions to be used with different patients.

The simple construction of the sampling sleeve from one or a few components produced from simple and inexpensive materials renders the sleeve viable for one-time-use only. The structural design of the sleeve also enables simple valve means to be used, and in accordance with a preferred embodiment, the sleeve also includes an auto¬ matic non-return or check valve which prevents blood from flowing back from the sampling tube. The simple sleeve construction also enables the provision of a simple blood indicator for indicating when a vein has successfully been punctured.

Brief Description of the Drawings

The invention will now be described in more detail with reference to the accompanying drawings, in which

Figures la and lb are axial section views of the inventive device, where Figure la illustrates the sampling sleeve without the sampling tube connected thereto, and Figure lb illustrates the sampling sleeve with the sampling tube connected;

Figures 2a and 2b are section views taken on the lines 2a-2a and 2b-2b respectively in Figures la and lb;

Figures 3a and 3b illustrate two alternative embodi¬ ments of the flow valves included in the embodiments of Figures 1 and 2, with the valves being shown in their closed and open states respectively;

Figure 4 is an axial section view of an alternative embodiment of the invention;

- Figure 5 is an axial section view of a further alter¬ native embodiment of the invention;

Figures 6a and 6b illustrate still another alterna¬ tive embodiment of the invention illustrated in Figure 1;

Figures 7a and 7b illustrate a further alternative embodiment of the invention illustrated in Figure 1, and Figure 7c is a sectional view taken on the line 7c-7c in Figure 7a;

Figures 8a and 8b illustrate an alternative embodi¬ ment of the invention illustrated in Figure 1, including a non-return valve and blood indicator, and Figure 8c is an enlarged vertical sectional view of the valve head; and

- Figure 9a is a side view of an alternative embodiment of the cylindrical part of said sleeve, and Figure 9b is a sectional view taken on the line 9b-9b in Figure 9a. Detailed Description of Preferred Embodiments of the Invention

Figures la,b - 2a,b illustrate an embodiment of a dis- posable sleeve 10 which incorporates a valve function, in accordance with the invention. The open end of a sampling tube 12 is sealed by an elastic stopper 14, for instance a rubber stopper, in an airtight and liquid- tight fashion. The stopper is formed so that it can be pierced by a needle and so that the hole formed by the needle will reseal automatically as the needle is with¬ drawn from the stopper. The sampling tube 12 is evacu¬ ated of air, so as to generate an internal subpressure.

The disposable sleeve 10 is preferably a one-piece structure manufactured from a plastic material, and is open at one end thereof so as to enable the sampling tube 12 to be pushed into the cylindrical sleeve 10. The other end of the sleeve 10 is provided with an end- part 15 which is provided with a centrally positioned, inwardly directed needle 16 and a preferably eccentri¬ cally positioned outwardly extending connector 22. An angled channel 20 extends from one orifice in the con¬ nector 22, along the end-part 15 and through the inter- nal needle 16.

The connector 22 is a standardized fitting for standard injection needles and consists, for instance, of a Luer, Record or like standard fitting to which needles from a standard needle assortment can be connected. When taking a sample from the vein of a patient, the needle is preferably inserted in a direction which is as paral¬ lel as possible with the direction of the vein, since otherwise there is a risk of also piercing the back wall of the vein, particularly in the case of fine veins. An eccentrically positioned connector 22 with a so-called Loeb-fitting, enables the standard needle connected to the connector 22 to be inserted at a better angle than otherwise, therewith facilitating puncturing of the vein. The connector 22 may also be placed centrally on the end-part 15, although the eccentric positioning of the connector is preferred, among other things because it facilitates puncturing of a vein, and because the lateral position of the connector provides more space for accommodating both a valve function and an indicat- ing function, as described in more detail herebelow.

The sampling sleeve illustrated in Figures 1-2 solves the problem of blood spillage when changing sampling tubes with one and the same needle inserted in the patient's vein, in that the inner needle 16 is formed inte-grally with a flow valve 26. This inner flow valve 26 is formed in the needle between the obliquely cut needle point 18 and the end-part 15 of the sleeve, wherein in its non-activated state, the flow valve functions to close the passage through the angled chan¬ nel 20 between the connector 22 and the point of the needle. The needle is made from a resilient material, and the flow valve is formed by biasing the walls into abutment with one another in one section of the needle, see Figures 2a-b, so as to close the channel and prevent blood from flowing therethrough. When the sampling tube, with its rubber stopper 14, is pushed into the sleeve 10, the needle point 18 pierces and perforates the stopper. When the stopper reaches the valve section 26 of the needle, the elastic material from which the stopper is made presses against the end-parts 30 of the valve so as to open the inner passageway 20, as shown in Figure 2b, whereupon blood will be drawn into the sam¬ pling tube as a result of the subpressure prevailing therein. The valve section 26 may also take other forms in its non-activated state, for instance the forms illustrated in Figures 3a and 3b. When the sampling tube is full and is withdrawn or pushed from the sleeve together with the rubber stopper, the valve section will return to its original non-activated form, therewith immediately shutting-off the blood flow.

Figures 4 and 5 illustrate two further valve means, both of which are formed integrally with the sampling sleeve 10. In the Figure 4 embodiment, the valve 26 has the form of a tongue 24 which forms an integral part of the end-part 15 above the channel 20, said tongue lying against the angled edge 25 of the channel such as to stop the flow of blood when the valve is in its non- activated state. When the stopper 14 in the sampling tube is penetrated by the needle 16, the tongue 24 is forced up by the stopper, therewith opening the valve and allowing blood to flow through the channel. In the case of the Figure 5 embodiment, the needle is twisted about itself, so that the inner channel 20 is closed when the needle is in a non-activated state. As the twisted needle penetrates the rubber stopper, the needle is untwisted and therewith opens the channel 20.

Figures 6a and b illustrate a further alternative em- bodiment of the flow valve 26. In this case, two dia¬ metrically positioned wings 32 are formed integrally on the outside of the needle 16. The channel 20 is provid¬ ed with two mutually opposing lips 34 which are formed integrally with the channel walls and which function to close the channel 20 when the wings 32 are in their non- activated, mutual positions, i.e. extend horizontally. As the sampling tube 12 is pushed into the disposable sleeve 10 and the rubber stopper is pierced by the needle, the wings 32 are forced upwards so as to mutual- ly separate the inner lips 34 and therewith open the channel 20. When the sampling tube is removed from the sleeve, the wings return to their neutral positions, and thus also the lips 34, therewith closing the channel.

In the case of the embodiment illustrated in Figures 7a-c, the valve 26 is comprised of two separate parts, one of which is a centric pin 36 which is formed in¬ tegrally with the sleeve and the outer part of which widens into a spherical head 38. As will be seen from Figure 7c, the neck 40 of the pin 36 is provided with a number of symmetrically positioned grooves 42. Firmly welded to the periphery of the inner end-part 15 of the sleeve 10 is a relatively rigid, but slightly elastic, plastic diaphragm 44. The diaphragm 44 is curved around the head 38 and therewith forms an abutment surface 46 which, in a neutral position, sealingly abuts the spherical head 38 of the valve so as to close the blood passageway through the sampling sleeve. The diaphragm continues from the abutment surface 46 to form a widened cavity 48 and thereafter tapers to form a pointed needle 16. The bottom of the sleeve 10 is also provided with internal grooves 50, the function of which will be described herebelow. Figure 7b illustrates how the valve 26 is opened when the sampling tube, together with the rubber stopper, is pushed into the sleeve. Thus, the diaphragm 44 is pushed up against the bottom of the sleeve and in its furthest inserted position lies against the grooves 50 on said bottom surface. The grooves 50 on the bottom surface and the grooves 42 on the pin ensure that blood will flow uniformly through the passageway.

Although not shown, the sampling sleeve illustrated in Figure 7 may be provided with a non-return valve, for instance in the form of a flexible, funnel-shaped flange mounted on the underside of the spherical head. The downwardly hanging flange is forced to one side by the blood that flows into the cavity 48 and from there into the sampling tube. If, on the other hand, there occurs a drop in pressure in the vein or an increase in pres¬ sure in the sampling tube, the soft and pliant flange is forced out into sealing contact with the inner walls of the cavity, therewith preventing backward flow of the blood.

Figures 8a-8σ illustrate a preferred embodiment having a valve means 26 which, in this case, also functions as an automatic non-return valve. The valve means operates automatically in the event of a drop in pressure in the vein or in the event of a pressure increase in the sampling tube. This function is particularly important when using sampling tubes that contain different mixture substances which must not be allowed to flow back to the patient. The valve means 26 is displaceably mounted in an annular flange 52 formed integrally with the bottom of the disposable sleeve, as illustrated in Figure 8a. When the valve 26 is in the operational state illustrated in Figure 8a, the valve seals against the side of the annular flange so as to stop the flow of blood through the passage. As will be seen more clearly from Figure 8c, the valve body is comprised of two parts, partly a resilient, elastic rubber body 54 having a tubular lip 56, and partly a needle part 58. The needle part 58 is preferably made of a plastic material and consists of the needle 16 which is intended to penetrate or pierce the rubber plug 14 of the sampling tube, and of a sleeve 60 which is open at one end there¬ of and the outer diameter of which is slightly smaller than the inner diameter of the annular flange 52. The sleeve is provided with an opening 62 through which blood is intended to flow when the valve is open. The tubular lip 56 is arranged within the sleeve 60, as shown in Figure 8c. As the tubular tube 12 is pushed into the disposable sleeve 10 and the needle penetrates the rubber stopper 14, the valve body 26 is pressed against the end-part 15 of the sleeve. The elastic body 54 is thereby com- pressed, as shown in Figure 8b, so as to uncover the opening 62 in the valve sleeve 60 earlier covered by the sealing annular flange 52, such that the opening dis¬ charges into the channel 20. Blood will then flow through the channel and force the lip 56 to one side and continue down into the sampling tube. Alternatively, parts of the end-part 15 may be formed so as to spring- up slightly under the pressure exerted by the valve body, as shown in broken lines in Figure 8b. In the event of an increase in pressure in the sampling tube, or in the event of a pressure drop in the vein, the occurrent pressure difference causes the tubular lip 56 to be pressed against the inner wall of the sleeve 60, thereby closing the passage 62 and preventing the flow of fluid back to the patient. When a subpressure pre- vails in the sampling tube 12, as is normally the case, the lip 56 is flexed to one side so as to permit the flow of fluid. When the sampling tube 12 is withdrawn from the needle, the elastic body 54 and/or the resil¬ ient end-part 15 will spring back so as to again cover the opening 62 in the valve body with the inner walls of the annular flange 52.

In order to enable successful insertion of a needle into the vein of a patient to be verified, prior to connect- ing a sampling tube 12 to the sampling sleeve 10, a blood indicator 66 is arranged in the channel 20. In this case, the end-part 15 of the sampling sleeve is made of a transparent plastic material, so as to enable the indicator to be seen from the outside. It is imper- ative that the indicator will offer the minimum of resistance to flow, so that venous blood is able to flow into the indicator without the assistance of a subpres¬ sure in the sampling tube. This is achieved in accord¬ ance with the present invention by mounting in the channels 20 a bag-membrane 68 which is essentially empty of air and which when successfully penetrating a vein is filled with blood in the absence of any appreciable flow resistance. The blood-filled bag-membrane can be seen from outside the sampling sleeve, through the plastic material, thereby indicating that a vein has been punc- tured successfully and allowing the sampling tube to be connected to the sampling sleeve. Alternatively, the blood indicator may have the form of a part of the channel 20 which can be seen through the plastic materi¬ al of the end-part and which is connected to an expand- able hose which is empty of air and which can accommo¬ date the air that is displaced by the blood entering the blood indicator, such that said channel part will be filled with blood in the absence of any resistance when a vein is successfully punctured.

Figures 9a and 9b illustrate an embodiment of the dis¬ posable sleeve 10 in which the cylindrical part of said sleeve is adapted to accommodate sampling tubes of mutually different dimensions, for example so-called pediatric tubes of smaller diameter. In this embodi¬ ment, the cylindrical part of the disposable sleeve 10 is replaced with a thin cylindrical wall 70 which is stiffened by a plurality, preferably four, support bars 72 which extend along said wall, as shown in Figure 9b. The thin cylindrical wall 70 is free from the end-part

15 and is connected solely to the support bars 72. When using a sampling tube of smaller dimension, the thin wall parts located between the support bars are pressed inwards, as shown by the broken lines in Figure 9b, such that the previously convex wall-parts between respective support bars 72 now take a concave shape. These wall-parts are thereby able to act as supports when connecting sampling tubes of smaller dimensions.

In order to enable the sleeves to be stacked one in the other, one of the support bars 72 may be disconnected from the end-part 15. The disconnected support-bar 72, together with the encircling thin wall-parts 70, can then be pressed in against the opposite part of the cylindrical wall, so that the previously cylindrical sleeve now assumes a stackable U-shape. When the sleeve is to be used for taking a sample, the free support bar 72 and the encircling wall-parts are pressed back to their original positions.

It will be understood that the invention is not restric¬ ted to the aforedescribed and illustrated embodiments and that several modifications are conceivable within the scope of the following Claims. For example, a flexible tongue or flap may be attached to the wall of the channel 20 in some suitable manner, inwardly of the connector 22, such as to form a non-return valve.

Claims

1. A blood sampling device intended for coaction with a sampling tube having an internal subpressure and provid¬ ed with a sealing device that can be pierced by a needle, c h a r a c t e r i z e d in that the device includes an inner needle (16) which is intended to pierce or penetrate the sealing device (14) of the sam- pling tube (12), an outer, conical standardized con¬ nector (22) intended for connection with a standard vein-puncturing needle, an inner channel (20) which connects the connector orifice with the needle orifice, and an inner valve (26) which is arranged in the channel (20) and which is closed when in a non-activated state and which is intended to be opened automatically by the sampling-tube sealing device (14) when said device is penetrated by said needle (16).

2. A sampling device according to Claim 1, c h a r ¬ a c t e r i z e d in that the sampling device has the form of a cylindrical sleeve (10); and in that the inner needle (16) and the outer connector (22) are formed integrally with the sleeve (10) and are made from the same material as said sleeve.

3. A sampling device according to Claim 1, c h a r ¬ a c t e r i z e d in that the inner needle (16) is mounted centrically in the sleeve (10); and in that the outer connector (22) is mounted eccentrically in said sleeve.

4. A sampling device according to Claim 2, c h a r ¬ a c t e r i z e d in that the inner valve (26) is formed integrally with the sleeve (10), the needle (16) and the connector (22) and is made from the same materi¬ al thereas.

5. A sampling device according to Claim 1, c h a r - a c t e r i z e d by a blood indicator (66) provided in the channel (20), said indicator (66) including an expandable bag-membrane (68) which is substantially empty of air.

6. A sampling device according to Claim 1, c h a r ¬ a c t e r i z e d in that the inner valve is comprised of a valve head (26) which is provided with an opening and which is displaceably mounted in an annular flange (52) arranged centrally in the sleeve (10), said head being displacable against the action of a spring force

(54), wherein the opening (62) is closed by said annular flange (52) in a non-activated position and displaced into the channel (20) against the force of the spring means (54).

7. A device according to Claim 6, c h a r a c ¬ t e r i z e d in that the valve head (26) is comprised partly of the spring means (54), on which an elastic lip (56) is provided, and partly of a needle-part (58) which comprises an open sleeve (60) in which said opening (62) is arranged, and said needle (16) being intended to penetrate said sealing device; and in that the elastic lip (56) is intended to sealingly close the opening (62) in the event of an increase in pressure in the sampling tube (12) and to flex away from the opening when a sub¬ pressure prevails in said sampling tube (12).

8. A device according to Claim 5, c h a r a c ¬ t e r i z e d in that the blood indicator (66) is mounted in the channel (20) beneath a transparent part of the sleeve (10) and between the connector (22) and the valve head (26).

9. A device according to Claim 1, c h a r a c ¬ t e r i z e d in that the cylindrical wall of the sleeve (10) consists of thin, flexible wall-parts (70) which are fixedly attached to a plurality of supporting bars (72) which extend symmetrically along the mantle surface of said sleeve.