JPH0224137B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a blood sample collection device for collecting blood samples for blood gas analysis. In summary, the present invention relates to a blood sample collection device for collecting a sample of blood from a patient without contaminating the blood sample with air.

In order to know the state of the air intake function and electrolyte metabolism of the human body, the PH value of the arterial blood, ie the respective oxygen saturation, must be determined by blood gas analysis. Quantitative analysis of electrolyte components in blood can also be performed at the same time. In such blood tests, if the blood sample to be tested comes into contact with air or if air is mixed into the blood sample, the measured value may differ from the true state of arterial blood. , have an adverse effect on the measured values. In its most simplistic terms, blood gas analysis primarily analyzes the
Measurement of _PO2 and _PCO2 . Here, P represents the partial pressure of a specific gas in the blood. Note that PH measurements are usually performed. This is the "SATA" test.
Samples must be refrigerated whenever there is any time between sample collection and testing. When the sample comes into contact with air, there are two consequences. First, it tends to increase the indicated frequency of PO ₂ where the sample is in contact with oxygen. At the same time, some of the _CO2 in the blood sample may be lost, and this will lower the displayed degree of _PCO2 . In short, contamination of air blood samples results in a disproportional change in the results obtained by increasing the PO ₂ reading and lowering the PCO ₂ reading. Anticoagulants, such as heparin, are commonly used to prevent the sample from clotting within the shank of the needle or the body of the syringe. The anticoagulant serves two purposes: to fill dead spaces within the syringe and to lubricate the movement of the plunger contained within the barrel.

Probably the most commonly used device for blood gas samples is a standard hospital syringe. The needle of these syringes is first inserted into an aqueous solution of an anticoagulant such as heparin. After the heparin is inhaled into the syringe, some of it is expelled. This prevents any air from remaining in the dead space within the syringe and fills the remaining dead space within the syringe with the needle and liquid heparin. The syringe is then injected into the artery. Arterial blood pressure (approximately 200 mmHg) will push the syringe plunger outward until stopped by the operator. For this reason, many samples are too large. Furthermore, if the plunger is not a water-tight fit within the barrel of the syringe, excess blood under arterial blood pressure will squirt out of the syringe body and onto the operator. Additionally, if the operator becomes distraught or does not stop the outward movement of the plunger,
The plunger is largely forced out of the barrel of the syringe, thus losing the entire sample. In this case, of course, the patient would have to be re-punctured and the equipment would also have to be thoroughly cleaned, which is overall highly undesirable.

Many proposals have been made in the patent literature and commercial market to solve such problems. For example, Hatsuno U.S. Pat. No. 3,930,492
A syringe is proposed that has a stopper that fits into a narrow portion of the proximal end of the syringe and has a rubber stopper at its proximal end. The stopper is punctured by a needle contained in the holder until it reaches a dead space containing liquid heparin. The heparin is then expelled through the needle body, thus expelling the air from within the syringe and filling the hollow shaft of the needle with heparin, so that the device is ready to take a sample. The blood sample collection device sold under the trademark TERUMO also includes the use of an adapter for a blood gas analyzer, thus requiring a procedural change for the practitioner.

An arterial blood sample collection device is proposed in US Pat. No. 4,041,934 to Genese of Abbott Laboratories. This device is extremely complex and, to the inventor's knowledge, has not been commercially produced. The device includes a bayonet that punctures a membrane at the rear of the syringe, the membrane forming a chamber containing heparin. Therefore, when the plunger is pushed proximally, heparin is ejected by the bayonet into the front of the syringe. Further depression of the plunger causes excess heparin to be injected into the needle attached to the protruding neck of the syringe. Moreover, the arterial pressure of the blood will force the stopper 18 distally until the appropriate amount of sample is taken.

Also, Emde Corporation
Corporation) by “Mosquito Bladder”
Gas Sampler” (MOSQUITO BLOOD
A device sold under the name GAS SAMPLER was launched on the market. This device is US Patent No. 4133304
listed in the number. The Mosquito Blood Gas Sampler uses a capillary blood collection device. Crystalline heparin, rather than an aqueous solution, is used within the barrel and needle hub. Additionally, the device uses an air vent in the form of a monofilament fishing line placed between the tube and the rubber stopper. Removal of the monofilament fishing line leaves a sufficient vent in the rubber stopper to vent the air within the tube. However, even when performed under perfect conditions, blood comes into contact with the air when the air in the syringe is evacuated. Since this device is not always bubble-free, the inside of the syringe and stopper are treated with silicone to minimize residual air bubbles. Another disadvantage of the device relates to the changes in practice required of the therapist. Underfilling occurs. This leaves an air vent between the stopper and the inner barrel wall, making it difficult, if not impossible, to apply subatmospheric pressure to the syringe to complete the sample collection once the monofilament thread is removed. It is.

Additionally, Marquest Medical Products, Inc. has marketed a device called ``OMNISTIK'' or ``MINISTICK,'' which uses similar technology.

The last device on the market, known as the "Deseret System", uses a plunger with an axially disposed hole. This syringe uses a hydrophobic membrane. This membrane closes the pores that first come into contact with blood. Therefore, it is necessary to keep the injection needle vertical in this device. This is because injecting at 45° will lead to underfilling and will produce larger bubbles than at 90°. This poses considerable practical problems since most punctures or injections are performed at 45° rather than 90°. Furthermore, this device leads to the fact that the blood sample itself expels residual air from the barrel of the syringe, thus opening the way to sample contamination through contact with the expelled air.

Referring in detail to the drawings, the injection needle N is of standard construction consisting of a point (or piercing end) 1, a hollow shaft 2, a transparent plastic hub 3 and a connecting collar 4. The inner body of the syringe consists of a transparent barrel B having a graduated tube-shaped portion 6 of uniform inner diameter, which can be made of glass or plastic. Disposable plastic tubes are particularly contemplated for the present invention.

A nozzle 7 with a reduced diameter is provided at the base end of the cylinder B. The nozzle 7 has a protruding neck 10 which is adapted to fit into the hollow part of the hub 3 of the injection needle N. A collar 11 is cast on the protruding neck 10 (that is, formed using a mold).
is provided. The collar 11 has a large thread 12, known as a "LEUER LOCK", which engages the coupling collar 4 of the hub 3 of the needle N.

The cylinder B has a flange 1 extending laterally at the other end.
It has 4. For convenience in the description of this application, the needle end of the syringe, including the nozzle portion and the protruding neck, will be referred to as the "proximal end", whereas the other end having a circular laterally extending flange 14 will be referred to as the "proximal end". The part shall be referred to as the "terminal part."

The expanded seal ring 16 is located inside the main body of the cylinder B.
and preferably rubber (i.e. rubber)
Alternatively, a floating stopper 15 made of elastic polymer is inserted. The floating stopper 15 is made to fit snugly against the inner wall of the tubular part 6 of the chamber formed by the cylinder B, but is allowed to move smoothly and easily up and down within said inner wall. For convenience of explanation, the space or chamber between the floating stop 15 and the nozzle neck 10 is designated 18, and the space or chamber between the distal end of the floating stop 15 and the plunger 20 is designated 19.
Plunger 2 inserted into the inside of cylinder B in the axial direction
0 has an axially arranged gas passage 21 or hole. At the end of the plunger 20, a rubber stopper 22 operatively connected thereto and having a sealing ring 23 effectively seals the plunger 20 and the tube B with the inner wall and facilitates the easy reciprocation of the plunger 20 within the tube B. It has been inserted so that it can be exercised. A gas passage (ie, vent) 21 is provided in communication with the chamber 19, extending through the rubber stopper 22 and opening to the outer portion of the device via an orifice 25.
Plunger 20 is formed with a raised annulus 26 and further includes a laterally extending flange 24. When the plunger 20 is in the depressed position, the flange 24 is aligned with the laterally extending flange 14 of the barrel B.

As previously stated, the purpose of the present invention is to obtain samples of arterial blood for blood gas analysis. As previously mentioned, it is particularly desirable to collect samples in which the arterial blood has been kept free from contact with air. One goal of the invention is therefore to keep air out of the chamber 18 between the proximal end of the floating stopper 15 and the narrow portion of the nozzle 7 as much as possible. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a method for completely eliminating air from dead spaces within chamber 18.

As mentioned earlier, heparin H is usually used as an anticoagulant to prevent blood collected within the hollow shaft 2 of the needle end or within the narrow part of the nozzle of the syringe body from coagulating. has been done.
As can be seen in FIG. 2, when the present invention is used in a prepackaged condition, liquid heparin H is deposited in the space or chamber between the distal end of the floating stopper 15 and the protruding neck 10 of the nozzle 7. 18 can be pre-packaged.

Other methods that can be used to inject heparin into the chamber 18 of the syringe while filling the hollow shaft 2 of the needle with anticoagulant and removing air from the dead space chamber 18 are commonly available in hospitals. Insert the tip 1 of the syringe needle into a sterilized anticoagulant bottle and draw a small amount into the chamber 18.
The needle is then inverted so that it is facing upward, and the air and residual heparin are expelled, leaving the heparin in the last part of the dead space in the chamber 18 and in the hollow shaft 2 of the body of the needle N.

The sample amount is indicated by scale 8. Cylinder B
The scale 8 on the surface takes into account the amount of displacement of the floating stopper 15. Therefore, by positioning the proximal end of the stopper 22 at a position on an appropriate scale corresponding to the desired sample amount, when the injection needle N is punctured into the artery in a standard manner, the floating stopper 15 is caused by the arterial blood pressure. When pushed towards the distal end, the rubber stopper 22 and the plunger 20 act as a stop for the floating stopper 15 and thus simultaneously evacuate the air in the chamber 19. According to this method, arterial blood never comes into contact with air. The professional can inject the sample into a blood gas analyzer or refrigerate the sample for later testing.

As mentioned earlier, blood gas analysis is performed for the purpose of evaluating the air intake function of the cardiovascular system. The measurements made by blood gas analysis are primarily of the PO ₂ and PCO ₂ concentrations of arterial blood samples.

When contamination of the sample by air or oxygen enters the sample in any form,
It tends to increase the displayed degree of PO ₂ , and also
PCO ₂ incidentally by letting CO ₂ escape into the air
Decrease the display frequency. Therefore, when using the device in which the dead space chamber 18 in the syringe body is filled with prepackaged heparin or is filled with aqueous heparin and the residual air is then evacuated before administering the injection. , contact of the arterial blood sample with air or oxygen is completely eliminated. Furthermore, since the plunger 20 is preset according to the desired sample amount, it is possible to repeatedly collect samples without losing them, without getting blood around the rubber stopper 22, and without contaminating the rubber stopper 22. can.

However, in many cases the patient is in critical condition. Therefore, when bodily functions are in a state of marked decline, or during coronary artery occlusion or after surgery, blood pressure drops dramatically and sometimes cannot be measured. In such cases, it is necessary to apply subatmospheric pressure to the syringe in order to collect the sample. Furthermore, by using this device, it is possible to perform bimanual injections when arterial blood pressure is so low that even locating a blood vessel is difficult. In these cases tubular adapters can be used. This is connected to a tube 34 including the connecting member 30 in FIG.
Shown as The connecting member 30 is formed by a hollow boss having an outer diameter complementary to the gas passage 21 and having a flange 33 which can be fitted into the gas passage 21 and acts as a stop. Ru. A hollow conical adapter (ie, attachment device) 35 attached to the other end can be easily mated with a mouthpiece 39 or with an aspirator valve 38. In these cases, the proximal end of the rubber stopper 22 of the plunger is set to an appropriate scale and the injection is performed. Subatmospheric pressure is applied by oral suction through tube 34 or by actuating a suction valve 38. The floating stopper 15 is then drawn toward the distal end and comes into contact with the proximal end of the plunger stopper 22.

It is necessary to aspirate the sample in other cases, such as when underfilling occurs due to an obstruction in the hollow shaft 2 of the injection needle N or due to other problems. This can be done by simply placing your finger over the end of the gas passage 21 and pressing the plunger 2 as shown in FIG.
This can be done extremely easily by adding reciprocating motion to zero. According to Boyle's law, room 19
The pressure within will cause the floating stop 15 to move relative to the plunger stop 22. This is shown by the imaginary line. In either case, by closing the gas passage 21 with a finger or with the stopper member 42 and then aspirating with the plunger 20, the sample can be aspirated until proper blood flow is resumed. The stopper member 42 includes a solid boss 43 and a flange 4 having an outer diameter that complements the gas passage 21.
4, and a nipple 45 which is adapted to be easily removed by the fingers.

Some experts oppose the use of aqueous heparin when taking blood samples. Such thinkers argue that air contamination is possible through contact of blood with aqueous heparin solutions. They therefore propose a syringe containing dry heparin within the hollow shaft 2 of the barrel and needle. This embodiment can be designed using the present invention as shown in FIG. It will be appreciated that floating stop 15 is shown in FIG. 3 as including a projecting boss 17. As shown in FIG. This protruding boss 17 is connected to the end of the floating stopper 15 and the neck 1 of the syringe.
It fills most of the chamber 18, which is the dead space between 0 and 0. When using this device, pre-fill the syringe with liquid heparin and expel the aqueous solution so that the device is pre-heparinized.
The protruding boss 17 of the floating stopper 15 can then be used to minimize residual air in the dead space chamber 18. Heparin prevents blood from coagulating and also serves to some extent as a lubricant for the floating stopper 15 and rubber stopper 22 within the barrel of the syringe body. In this variant, it is not always possible to completely remove residual air. However, if the walls are siliconized, the least amount of bubbles will remain. If bubbles appear, invert the injection needle so that it is facing upwards and tap barrel B with your finger, and the bubbles will usually disappear. Such a minimal amount of air bubbles will not have a significant sub-effect on the displayed power if the air bubbles are immediately dissipated and prevented from contaminating the sample entering the blood gas analyzer.

While many variations may occur to those skilled in the art from the detailed description set forth above, the foregoing description is illustrative and non-limiting in nature, and equivalents within the scope of the claims are intended to cover the present invention. include.

[Brief explanation of drawings]

FIG. 1 shows an elevational view of a device according to an embodiment of the invention, FIG. 2 shows a partial sectional view of the device according to a modified embodiment of the invention, and FIG. 3 shows another modified embodiment of the invention. 4 shows a perspective view of a tubular adapter that can be used in conjunction with the device of the present invention, and FIG. 5 shows a perspective view of a tubular adapter that can be used in conjunction with the tubular adapter of FIG. 4. 6 shows a front view of a mouthpiece, FIG. 6 shows a front view of an aspirator valve that can be used in conjunction with the tubular adapter of FIG. 4, and FIG. FIG. 8 shows a front view of a stopper member that can be used to
An elevational view, partially in section, showing the device shown in use, with solid lines showing the plunger and floating stop in the depressed position and phantom lines showing the plunger and floating stop in the withdrawn position. Indicated by location. B...Cylinder (cylindrical member), H...Heparin, N...
Injection needle (hollow needle), 1... point (i.e., piercing end), 2... hollow shaft (hollow shaft part), 3... hub (connection hub), 6... tube-shaped part (tube-shaped member) , 8... Scale, 10... Cervical, 15
...Floating stopper, 16...Seal ring, 20
...Plunger (plunger member), 21...
...Vent passage, 22...Rubber stopper (seal device), 23...Seal ring, 25...Orifice (external orifice), 30...Connection member (hollow connection device), 34...Tube (tube-shaped member), 35 ...adapter (i.e., attachment device), 39...mouthpiece, 42...stopper member (rubber stopper), 43...solid boss (protruding boss).

Claims (1)

[Scope of Claims] 1. A cylindrical member defining a tube-like member of uniform inner diameter and having an inner wall portion and a proximal end portion of reduced inner diameter including a protruding hollow neck; and a piercing end portion, an elongated hollow. a hollow needle having a shaft portion and a connecting hub connected to the hollow neck of the tubular member; and at least one outer circumferential sealing ring slidingly engaged with an inner wall of the tubular member; a floating stopper movable in both directions along a directional axis; a plunger member in intimate sliding contact with the inner wall of the tubular member; and a sealing device extending axially through the plunger member and within the tubular member. a plunger member having a central vent opening directly into the plunger member and having an openable external orifice for introducing and expelling air. 2. A blood sample collection device according to claim 1, wherein the barrel member is made of a transparent material so as to directly indicate the first passage of blood into the sample chamber. 3. A blood sample collection device according to claim 1, wherein the connecting hub of the hollow needle is formed of a transparent material so as to directly indicate the first passage of blood entering the device. 4. The device according to claim 1, wherein the sealing device of the plunger member includes at least one sealing ring and a centrally bored air passage aligned with the central air passage of the plunger member. A blood sample collection device including a rubber stopper having a rubber stopper. 5. The device according to claim 1, wherein the device comprises: a hollow coupling device for attaching to the proximal end of the central air passage of the plunger member; a tubular member including an attaching device; A blood sample collection device having an auxiliary device including a mouthpiece for attachment to the device. 6. A blood sample collection device according to claim 1, wherein the device includes a closure device for closing an axially disposed central vent passageway orifice at a distal end of the plunger member. 7. The device according to claim 6, wherein the closure device for closing the orifice of the axially arranged central air passageway comprises a projecting boss having an outer diameter complementary to an inner diameter of the central air passageway. A blood sample collection device that is a rubber stopper.