WO2017049363A1

WO2017049363A1 - Volumetric dispensing of blood

Info

Publication number: WO2017049363A1
Application number: PCT/AU2016/050898
Authority: WO
Inventors: Damien CONWAY; Patrick Dunn; Huw Wallis; Willem Mees Van Der Bijl
Original assignee: Venipoc Pty Ltd
Priority date: 2015-09-23
Filing date: 2016-09-23
Publication date: 2017-03-30

Abstract

A blood dispenser, including an interface for receiving a sample tube containing blood and forming a fluid communication with said tube, a pump for transferring the blood from the tube to a dispensing chamber, and a control mechanism to permit an operator to select a volume of blood to be dispensed, so that the operator selects a volume of blood to be dispensed and operates the pump to release the selected volume of blood to said dispensing chamber.

Description

VOLUMETRIC DISPENSING OF BLOOD

Technical Field\

[0001 ] The present invention relates to the safe and controlled dispensing of blood, particularly for point of care testing and similar applications.

Background of the Invention

[0002] Pathology tests, such as blood tests, have traditionally been provided using large, centralised pathology laboratory facilities, whether within hospitals or using private providers. These operations continue to play an important role.

[0003] However, there has been a growth in recent years of point of care (POC) tests. These are tests that are provided typically by the clinical personnel providing care to a patient, rather than being conducted in a central facility. POC tests provide clinical personnel with rapid results, to facilitate treatment in a timely way. The range of available tests is increasing significantly and may be expected to continue to increase with further developments.

[0004] POC tests typically use a test cartridge or test strip, with blood usually taken using a finger prick technique using a disposable lancet. The blood is applied to the test, in some cases a buffer is added, and over a period of seconds to minutes a result is obtained. Each test requires a minimum quantity of blood, which could be any volume between 2.5 and 300 μΙ, but is usually below 100μΙ.

[0005] Because of the increasing diversity and speed of POC tests, there are many clinical situations in which it is useful to conduct multiple POC tests. For example, in cases of acute chest pain, acute abdominal pain or any other situation in which the conduct of haematology and biochemistry POC tests with rapid provision of results to the clinicians caring for the patient is critical for making a diagnosis and providing appropriate treatment.

[0006] Another example of the utility of POC tests is in acute febrile illness and suspected cases of infectious disease, where there are several POC tests available which allow clinical staff to determine whether the patient has any one of a number of infections which may require rapid assessment, isolation, treatment and contact tracing.

[0007] To conduct multiple POC tests, one conventional approach is to obtain multiple finger prick blood specimens using a lancet from many of the patient's fingers. This is not a convenient process, as it results in a patient with multiple lancet punctures on the patient's fingers. It is relatively time consuming and distressing for the patient to receive multiple finger pricks, with accompanying massaging and handling by the medical staff. This is often not practical for elderly patients, or for a patient whose skin is calloused or poorly perfused with blood.

[0008] Another approach is to take a blood sample by venepuncture in the conventional way, as for conventional pathology laboratory tests. However, while this provides a sample, the sample is generally in a container that is specifically designed not to be opened at the point of care and treatment. In some cases, it has been known for staff to pry open the stopper of the blood tube, in order to access the specimen inside with a syringe. This represents a biohazard and blood exposure risk for the operator and their colleagues. Further, this does not provide any mechanism for dispensing the blood in a controlled way.

[0009] Products exist which enable the operator to access a blood specimen taken by venepuncture inside a vacuette®, vacutainer® or similar tube. These devices are intended for providing a smear of blood or blood film on a microscope slide, for microscopy or similar purposes. Such devices are not suitable for providing specimens for use with POC tests, and do not allow for accuracy in or control of the volume dispensed.

[001 0] Another alternative is access the blood specimen in the blood tube with a blood transfer device which allows aspiration of blood into a syringe, which can then be dispensed onto the required POC tests. This approach requires the operator to dispense the blood from a syringe onto the POC test device. This process involves multiple steps and components and does not facilitate the dispensing of a specific measured volume of blood in a safe controlled way. This procedure is not reliable in terms of providing accurate volumes of blood for POC tests and it represents an exposure risk for the operator and their colleagues.

[001 1 ] It is an object of the present invention to provide a device and method for safely dispensing controlled volumes of blood, particularly for point of care testing situations.

Summary of the Invention

[001 2] In a broad form, the present invention provides a blood dispenser, which receives a tube of blood taken by conventional venepuncture. The dispenser is able to dispense controlled volumes of blood, for example for different POC tests, without requiring any unsafe blood transfer techniques by the operators. [001 3] In one broad form, the dispenser uses the tube and the corresponding seal as part of a pump for dispensing controlled volumes of blood.

[0014] According to one aspect, the present invention provides a blood dispenser, including an interface for receiving a sample tube containing blood and forming a fluid communication with the tube, a pump for transferring the blood from the tube to a dispensing chamber, and a control mechanism to permit an operator to select a volume of blood to be dispensed, so that the operator operatively selects a volume to be dispensed and operates the pump to release the selected volume of blood.

[001 5] Accordingly, it can be seen that implementations of the present invention allow for the safe dispensing of measured volumes from one blood specimen, using a device which is a single use, disposable product. This allows for various applications, particularly the use of a single venepuncture sample for multiple POC tests.

[001 6] Further, in preferred implementations, entirely conventional venepuncture blood sample techniques and apparatus are used to take the sample from the patient. These procedures are well known and controlled, and have established safety protocols and procedures. This is particularly important when dealing with a potentially hazardous material such as blood. The sample tube of blood produced from this procedure is then received in a device according to implementations of the present invention.

Brief Description of the Drawings

[001 7] Illustrative implementations of the present invention will now be described with reference to the accompanying figures, in which:

[001 8] Figure 1 is a series of photographs illustrating the use of an implementation of the present invention;

[001 9] Figures 2A to 2F are views in section showing the operation of the implementation of figure 1 ;

[0020] Figures 3A to 3C shows external views of an implementation of the present invention;

[0021 ] Figure 4 is a detailed sectional view illustrating the spike and vent operation of the implementation of figure 2;

[0022] Figure 5 is a view of a suitable blood tube for use with the present invention; [0023] Figure 6 shows detailed views of the valve components of figure 2; and [0024] Figure 7 is an exploded view of the implementation of figure 2. Detailed Description of the invention

[0025] The present invention will be described with reference to various implementations. It will be appreciated that the implementations described are provided solely for the purposes of illustration, and are not limitative of the scope of the invention.

[0026] Whilst the implementations will be described primarily with respect to the vacuette® and vacutainer® products, available from Becton Dickinson, it will be appreciated that the invention is in no way limited to such products. In suitable alternative implementations, other forms of blood sample tube could be used, for example the products supplied by Sarstedt.

[0027] The tubes may be of the evacuated type, in which the blood is drawn in partly under vacuum, or of a non-evacuated type. While commercially available products are preferred, the implementation could use custom products. Modifications to the implementation would be required, as would be understood by those skilled in the art, corresponding to the design of the sample tubes and their seals.

[0028] The general concept of the implementations to be described is that a sample of blood is taken from the patient by a conventional venepuncture procedure. The sample is in a tube, which tube is then connected to the dispenser according to the present invention. This enables selected volumes of the sample to be dispensed from the tube through the dispenser, in order to provide blood for multiple POC tests. The blood could be used for other tests, stored, or otherwise dealt with, if required. That is, the usage of the dispenser, and accordingly the scope of the present invention, should not be considered as limited to POC tests. However, the primary context is the use of the blood for multiple POC tests.

[0029] Figures 3A, 3B and 3C illustrates the overall design of an implementation of the present invention. The dispenser, generally designated as 10, includes a body 1 1 . A recess 14 allows for a sample tube 20 to be inserted. A discharge tube 1 3 extends from body 1 1 . The outside of body 1 1 is threaded , and carries a dosage collar 12, which is moved up and down to select the required volume of blood to be dispensed. A slot 38 is visible in figure 3C, which allows for dosage collar 12 to interact with the internal mechanism of the dispenser, as will be described in more detail below. [0030] The dosage collar 12 travels along the thread in body 1 1 . Volumetric markings 19 can be seen. Key 1 7 serves as a stop, so that the tube/plunger assembly stops when it hits the dosage collar 1 2. Key 17 includes a tab that protrudes through slot 38 in body 1 1 which allows for key 17 to contact dosage collar 12. Handle 29 acts as a stop when spring 1 8 pushes key 17 and needles 31 and 32 upwards. The end of the slot in body 1 1 acts as a stop when depressing tube 20 if dosing collar 12 is set to 100μΙ or rotated even further.

[0031 ] Figure 7 is an exploded view of the implementation of figure 3. It can be seen that tube 20 has an associated seal 26. In use, vent/spike assembly 30 passes through the seal into tube 20. Valves 23, 24 serve to create the appropriate pressure changes for discharge, as will be described in more detail below. Plunger 40 is attached to vent/spike assembly 30 and operatively travels inside discharge tube 13, against the return force of spring 1 8.

[0032] Figure 5 shows in more detail a suitable 4 ml blood tube 20, with a seal 26 at the top. In this device, seal 26 retains the specimen of blood within the tube, as well as the partial vacuum inside the tube.

[0033] Figure 1 illustrates, by a series of successive images, the process to be followed when operating a device according to figure 3. Figure 1 shows dispenser 10 ready for use at step 1 . A vacuette® tube 20 is inserted into recess 14 at step 2.

[0034] In order for the pump and dispensing mechanism to operate correctly, dispenser 10 must have air removed and blood commencing to flow within the device. To achieve this, tube 20 is depressed, released, and pressed again. In the implementation described, this will remove the air from the dispensing mechanism. This is shown in the 3 images associated with step 3.

[0035] The user then sets the required dosage by rotating dosage collar 12 to the corresponding volume marking, visible on the side of dispenser 10. This may be, for example printed on the inside (if transparent) or outside of the dispenser, or over-moulded in another colour or as applied as an in-mould decoration or applied externally as a sticker, and provides a guide for the operator.

[0036] It is emphasised that in preferred implementations, the present invention is intended to provide the user with greater control over the volume dispensed than current methods such as using a syringe or a pipette. However, the present invention could be implemented as a less accurate device to allow for reasonable approximate volumes to be dispensed, in order to split a sample among multiple POC tests. For example, the present invention could be implemented so as to dispense a fixed volume, rather than an adjustable volume.

[0037] At step 5, the priming cap 15 is removed and discarded. This serves to keep the discharge tube 1 3 clean and free from contamination in storage and the tip and valves protected in transport. It also serves to ensure that there is no accidental discharge of blood until the operator is ready to dispense. To prime the device, the user will need to depress and release tube 20 two or three times and will see blood flow through passage 16 inside transparent discharge tube 13 and into transparent priming cap 15.

[0038] At step 6, the tube 20 is depressed and acts as a pump to force the required volume, as selected by the dosage collar 12, from the discharge tube. This may be placed directly onto the test material of a POC test (not shown). This may be repeated as many times as required, consistent with the volume requirements for particular tests, and the quantity of blood in tube 20. The entire assembly is then disposed of in a sharps receptacle or similar facility, as the dispenser and blood tube contain blood and are accordingly a biohazard.

[0039] POC tests typically have a specific required volume of blood for their correct operation. A typical venepuncture sample will have 2.7ml to 1 0ml of blood. POC tests can require a specific volume between 2.5 and 300 μΙ, but most are less than 1 00μΙ and many are less than 50μΙ. It can be seen that the present approach will readily allow for multiple tests to be done in a typical situation.

[0040] For some applications, it is preferred that the blood tube has an anti-coagulant inside, for example EDTA or lithium heparin, as is commonly the case commercially, to prevent the blood clotting inside the device prior to application. POC test.

[0041 ] The present implementation is intended for use after a blood sample has been taken by venepuncture, in any conventional way. Millions of such samples are taken in clinics, hospitals and pathology laboratories every day, and so no further discussion of this well-known and widely practiced technique will be provided.

[0042] The example uses a threaded exterior surface to allow for the adjustment of a selected volume using a dosage collar. Alternative dose selection mechanisms could be used. For example, the collar may include corresponding internal indents, which align with external ribs on body 1 1 , creating a stepped dosing system instead of a continuous thread.

[0043] Figure 2 illustrates the mechanism of the present implementation, partly in section. Figures 2A to 2F correspond to the stages outlined in figure 1 . [0044] In figure 2A, the device is ready for use. Priming cap 15 is in place. Discharge tube 13 includes passage 16 for blood to pass through in use. Through recess 14, the vent/spike assembly 30 and tube seal 22 can be seen. As will be explained in more detail below, vent/spike assembly 30 allows for blood 21 to exit tube 20, and for air to enter to prevent a pressure lock in the tube.

[0045] In figure 2B, tube 20 has been attached, and seated inside tube seal 22. This seats the tube so that blood will not discharge backwards through recess 14. Tube 20 and seal 22 form a plunger type structure, with the inside of body 1 1 as the barrel, travelling up and down along with vent/spike assembly 30.

[0046] Figure 2C illustrates the first step in priming. Tube 20 is pressed down and then released twice. Spring 1 8 provides a return force to take the tube seal 22 and attached plunger 40, and hence tube 20 back to the top. As this occurs, valve 24 is shut. This action creates a vacuum in discharge tube 13 which pulls blood from tube 20, through, spike 32 and key 17, forces valve 23 open and which allows blood to flow into the discharge tube. This will not fill the discharge tube in one go as the volume that is moved is equal to the internal area of the discharge tube 20, not the internal area of the discharge tube 20 plus the internal areas of key 20 spike 32 and key 17, valve 23. Therefore priming the device two or three times is required. Figure 2D illustrates the return to the top.

[0047] Figure 2E illustrates the dose selection process. The user rotates the dosage collar 1 2 along the external thread, as discussed above, and selects the required volume. The higher up dosage collar 1 2 is rotated, the smaller the travel of tube 20 and hence the smaller the volume dispensed.

[0048] Once the dosage is selected, tube 20 is again depressed. This action forces plunger 40 and seal 22 through the discharge tube. Valve 23 is forced shut by the pressure and valve 24 opens allowing for the selected volume of blood to be expelled from the device from the discharge tube 13.

[0049] A series of valves are used to ensure correct operation. As can be seen in figure 2E, as tube 20 is depressed for priming, valve 23 closes and valve 22 opens. In figure 2D, as the tube is released and hence a vacuum is created in discharge tube 1 3 which opens valve 23 and valve 24 closes. Figure 2F shows dispenser 1 0 in the process of discharging blood (not shown) from discharge tube 13. Note filter 33, which serves to clean the incoming air so as to prevent contaminants from entering the blood specimen, and prevent any drips or backflow from the vent/spike assembly 30 exiting the device. It may be of any suitable type, for example a LOGICA 24 hour filter, or a cut section of PTFE filter paper, for example rated for 0.2 micron particles. [0050] The valves can be seen in more detail in figure 6. Top seal 23, which is illustratively a duckbill seal, and could also be, but not limited to a ball valve or silicone disc check valve, seals when tube 20 is depressed, and blood is being dispensed ( or used to prime the dispenser). Lower seal 24 seals when the tube 20 is released, and the spring forces the plunger back up.

[0051 ] Figure 6 also shows more detailed views of the tube seal 22, which acts as a plunger for the tube /seal assembly in use.

[0052] Figure 4 illustrates the operation of vent / spike assembly 30. This may be a pair of tubes, or a single tube divided laterally, or even a co-axial arrangement. Spike 32 allows blood 21 to exit the tube when a reduced pressure is created by spring 18 pushing tube 20 back up, as shown by arrow 34. The vent passage 31 is connected to the external air via filter 33. Thus, as blood 21 is forced out, air is permitted to enter equalising the pressure in tube 20.

[0053] Implementations of the present invention may be constructed from any suitable materials. It is noted that it is highly preferred that the device be disposable, and consequently long-term durable materials are not required. However, it is critical that the materials chosen do not contaminate or alter the blood specimen in any way which will interfere with the intended tests. Most of the parts of the implementation described may be formed from a suitable hard polymer material, for example ABS, polypropylene or similar materials. Seal components may be formed from appropriate conforming materials, for example silicone, EVA or TPE. The spike, including the long section on the plunger, through which blood will pass, vent and return spring, may be suitably formed from stainless steel. Of course, the invention is not confined to particular materials and any suitable material may be used.

[0054] Implementations of the present invention may be formed from any suitable material. It is preferred that the discharge tube at least is transparent, so that the blood can be seen when the device is primed and the operator can be sure that the intended volume can be dispensed.

[0055] While a specific implementation has been described, it will be appreciated that the invention, in the broadest sense, requires the insertion or connection of a sample tube into the device, and a controlled volume pump mechanism to allow blood to be dispensed. In one implementation, the dispenser may produce a fixed quantity of blood, rather than allow for a quantity to be selected by the operator. [0056] An alternative pump mechanism may be used, and in particular, a different sequence and set of seals and valves used. The details of the vent/spike, for example, will depend upon the mechanism and structure of the blood sample containers in use.

[0057] Other variations and alternatives will be apparent to those skilled in the art, and are encompassed within the general inventive concept disclosed.

Claims

1. A blood dispenser, including an interface for receiving a sample tube containing blood and forming a fluid communication with said tube, a pump for transferring the blood from the tube to a dispensing chamber, and a control mechanism to permit an operator to select a volume of blood to be dispensed, so that the operator selects a volume of blood to be dispensed and operates the pump to release the selected volume of blood to said dispensing chamber.

2. A blood dispenser according to claim 1 , wherein the interface for receiving the sample tube and the sample tube operatively form part of the pump.

3. A blood dispenser according to claim 2, wherein the pump is a reciprocating structure including the sample tube.

4. A blood dispenser according to any one of the preceding claims, wherein the control mechanism is an adjustable stop on the exterior of the dispenser.

5. A blood dispenser according to claim 1 , wherein the dispenser is adapted to be primed by the pump structure.

6. A blood dispenser according to claim 1 , wherein the control mechanism permits a fixed blood volume to be dispensed.

7. A blood dispenser according to any one of the preceding claims, wherein the interface includes a first passage for transferring blood from the tube, and a second passage for allowing air into the tube as blood is transferred.