WO2009087374A1

WO2009087374A1 - Locking system for blood bags

Info

Publication number: WO2009087374A1
Application number: PCT/GB2009/000028
Authority: WO
Inventors: Paul Lawrence Cervi
Original assignee: Basildon And Thurrock University Hospitals Foundation Trust
Priority date: 2008-01-09
Filing date: 2009-01-08
Publication date: 2009-07-16
Also published as: GB0800283D0

Abstract

This invention relates to a method for ensuring transfusion of blood to the correct patient, wherein the method comprises: (a) providing the patient with a first identification tag and a second identification tag; (b) allocating a blood bag to the patient containing the type of blood required by said patient; (c) directly attaching a locking mechanism to an outlet of the blood bag; (d) locking the locking mechanism with a signal generated by the first identification tag; and (e) unlocking the locking mechanism on the blood bag with a signal generated by the second identification tag. The invention also relates to a kit for ensuring transfusion of blood to the correct patient, wherein the kit comprises a first identification tag, a second identification tag and a locking mechanism.

Description

LOCKING SYSTEM FOR BLOOD BAGS

This invention relates to a method and kit for ensuring the transfusion of blood to the correct patient.

Transfusion of the wrong type of blood to a patient can lead to adverse reactions and possible fatal consequences. As a result, the transfusion step is tightly controlled to ensure that the patient receives a compatible blood type.

However due to the number of blood transfusions that occur each year (between 2 -3 million in the UK alone) , there is always the potential for error. For example, the medical worker may misread the type of the transfusion blood or the type of the patient's blood and administer the blood to the wrong patient. Errors may also be made when recording the patient's blood type in the patient record.

In the UK, five patients died as a result of being given incompatible blood, and this type of error contributed to the deaths of a further nine patients between 1996 and 2004. Consequently, there is a need for a new invention that can reduce or eliminate the possibility of error in delivery of a compatible blood type to the patient.

Thus, according to a first aspect of the invention there is provided a method for ensuring transfusion of blood to the correct patient, wherein the method comprises:

(a) providing the patient with a first identification tag and a second identification tag;

(b) allocating a blood bag to the patient containing the type of blood required by said patient; (c) directly attaching a locking mechanism to an outlet of the blood bag; (d) locking the locking mechanism with a signal generated by the first identification tag; and

(e) unlocking the locking mechanism on the blood bag with a signal generated by the second identification tag.

The invention provides the advantage of reducing human error factors related to delivery of the correct type of blood to the patient.

As used herein, the signal generated by the first identification tag which locks the locking mechanism may be referred to as the locking signal.

As used herein, the signal generated by the second identification tag which unlocks the locking mechanism may be referred to as the unlocking signal.

In one embodiment, the first identification tag comprises:

(i) electronically readable data, which may be used to generate the locking signal; and

(ii) a signal generator capable of converting the electronically readable data into the locking signal.

In one embodiment, the second identification tag comprises:

(i) electronically readable data, which may be used to generate the unlocking signal; and

(ii) a signal generator capable of converting the electronically readable data into the unlocking signal.

It will be appreciated that the electronically readable data on the first identification tag corresponds to the electronically readable data on the second identification tag. In one embodiment, the electronically readable data comprises an identifying number, e.g. a randomly generated alphanumeric password. In one embodiment, the code on the first identification tag is identical to the code on the second identification tag.

In another embodiment, the electronically readable data comprises patient identification information. As used herein, patient identification information is selected from one or more of the patient ID number, surname, forename, date of birth, gender, diagnosis and blood requirements, e.g. blood type (A, B, O) , rhesus factor and other requirements, such as antibody negative, leucocyte depleted, irradiated, CMV negative blood and/or a unique number for the specific transfusion episode.

In another embodiment, the electronic readable data comprises the results of a biometric scan, e.g. a retinal scan, thumb print, voice identification, and the like.

In one embodiment, the first identification tag and the second identification tag may be a Radio Frequency Identification (RFID) tag, a magnetic swipe card, a password system, a biometric device (such as a retinal scanner, thumbprint reader, voice identification unit, or the like) , or a linear or two-dimensional barcode using any one of many common barcode formats with a bar code reader.

In a further embodiment, the first identification tag is an RFID tag, and the second identification tag is an RFID tag.

As used herein, an RFID tag is an object that can be applied to or incorporated into a product, animal, or person for the purpose of identification using electromagnetic radiation that lies between audible and infrared radiation. An RFID tag contains at least two parts. One part is an integrated circuit for storing and processing information, modulating and demodulating a (RF) signal and can also be used for other specialized functions. The second part is an antenna for receiving and transmitting the signal, which can be read from several metres away.

RFID circuitry is well known to those skilled in the art and may be provided in a plurality of configurations, for example, passive and active. A passive tag requires no internal power source and depends for activation and operating power upon the signal emitted by a reader, whereas an active RFID tag includes an internal power source, which is used to power the integrated circuits and broadcast the signal to the reader. An active tag typically has a much longer range (approximately 500 m) and larger memory than a passive tag, as well as the ability to store additional information.

In one embodiment, the first identification tag and/or the second identification tag are passive RFID tags. In an alternative embodiment, the first identification tag and/or the second identification tag are active RFID tags. It will be appreciated that any commercially available RFID tag may be used. In a further embodiment, the RFID tag may have networking capabilities that would allow it to connect to a central server.

In a further aspect of the invention, there is provided a patient identification device, comprising a wristband, which is fixedly attached to the second identification tag. In one embodiment, the patient identification device is attached to the patient. The patient identification device decreases the risk of a patient switching the identification tag with another patient and being misidentified. As used herein, the term fixedly attached means the second identification tag may be permanently attached to the wristband. In yet a further embodiment, the second identification tag may form part (e.g. a unitary part) of the wristband.

In yet a further embodiment, the patient identification device additionally comprises the first identification tag wherein the first identification tag is detachably attached to the wristband.

As used herein, the term detachably attached means that the first identification tag is attached to the wristband in such a manner that enables it to be removed when required. It will be appreciated that it will be attached securely such that it cannot be removed accidently.

In one embodiment, where the patient's blood requirements, e.g. patient's blood type (A, B, O) and Rhesus blood group are unknown, the method additionally comprises collecting a blood sample from said patient and testing said blood sample to determine the type of blood required by the patient prior to step (b) .

In one embodiment, the patient identification device additionally comprises a blood sample receptacle, e.g. blood tube. This embodiment provides the advantage that each patient will have an associated identification tag with a blood sample receptacle for enhancing the blood typing and matching process . In the embodiment wherein the patient identification device additionally comprises a blood sample receptacle, a first identification tag may be fixedly attached to the blood sample receptacle.

The blood sample may be collected into the receptacle using standard blood sample collection techniques. In one embodiment, the first identification tag is removed from the patient and attached to the receptacle once the sample is collected into the receptacle. In an alternative embodiment, the blood sample receptacle may include the first identification tag (e.g. the first identification tag may be attached (e.g. fixedly attached) to the blood sample receptacle) . In such an embodiment, the blood sample receptacle may be detachably attached to the wristband.

It will be appreciated that wherein the first and second identification tags are not pre-configured to be identical, the electronically readable data may be copied and transferred from the second identification tag to the first identification tag.

Once the blood sample is collected, it is analysed to determine the characteristics of the patient's blood, for example the patient's blood type (A, B, O) and Rhesus group and also to determine if there are any other particular requirements for the patient, such as antibody negative, irradiated, or CMV negative blood. It will be appreciated that these procedures are well known in the art.

In one embodiment, the patient identification information is updated to record the results of the blood analysis, e.g. the blood type selected and the specific characteristics of the blood. This updated information may include the time and date of the test and any identifying number assigned to the blood sample. The updated patient identification information may then be transferred to the first identification tag and the second identification tag if it forms part of the electronically readable data.

In one embodiment, the blood bag is selected from the blood bank by comparing the compatibility of the transfusion blood with the patient's blood. Particular care is paid to selecting blood transfusion units of the correct ABO type and Rhesus group as errors in the assignment of these groups may lead to serious and potentially fatal transfusion reactions.

In another embodiment, the blood bag has a third identification tag, containing or encoding the blood group identification data of the transfusion unit, which would allow checking whether the transfusion blood type is compatible with the intended recipient.

In one embodiment, the locking mechanism comprises an electrically actuated lock. As the lock is transported with the assigned blood transfusion unit, it may be portable and battery powered.

In one embodiment, the lock controls the opening and closing of a clamp which seals the outlet ports of the blood transfusion unit. In a further embodiment, the locking mechanism comprises clamping means which, upon actuation, are configured to obstruct the outlet tube(s) of the blood bag and prevent transfusion. Thus once clamped, the blood cannot be connected to the patient. In an alternative embodiment, the lock may seal a transparent container, such as a plastic bag which must be opened to allow access to the transfusion unit.

In the preferred embodiment, where RFID tags are used as the identification tag mechanism, the lock also comprises an electronic printed circuit board (PCB) , which communicates with the RFID tags via an antenna. In the preferred embodiment, the RFID tags must be brought preferably to close proximity (less than 100 mm) of the antenna for the RFID tag signal to be read and recognised.

The PCB can be programmed to recognise/actuate only following the recognition of highly restricted specific tag identification signals. Such programming can be achieved by interfacing the PCB with a computer, or by using a remote control unit with infrared command signalling.

In one embodiment, the PCB is capable of reading the identification signal generated by the first identification tag, restricting the actuation of the locking mechanism to the identification signal of the first and second identification tags for one transfusion episode only. Thus the lock is controlled by an electronic circuit board which communicates with the locking mechanism and is capable of receiving the locking signal uniquely generated by the first identification tag and the unlocking signal uniquely generated by the second identification tag.

In a further embodiment, the locking mechanism comprises a sound-emitting device, for example, a speaker, a piezzo buzzer or the like. In a further embodiment, the locking mechanism additionally, or alternatively, comprises light emitting means, such as one or more LEDs, which may be the same or different colours (e.g. red, green, and/or yellow) . This would provide the benefit of a visual or aural indication to the user that the locking mechanism had been locked or unlocked.

It will be appreciated that the locking mechanism is locked by the locking signal. In one embodiment, the locking mechanism stores the signal in memory. Once the locking mechanism is locked, blood cannot be obtained from the blood bag in the normal manner.

It will be appreciated that the locking mechanism is unlocked by the unlocking signal. In a further embodiment, unlocking of the locking mechanism may occur when the electronically readable data stored within the locking mechanism is matched with the electronically readable data stored on the second identification tag.

If the electronically readable data stored within the locking mechanism does not match with the electronically readable data stored on the second identification tag, the locking mechanism will not unlock, and will therefore not allow blood to be drawn from the blood bag.

In a further embodiment, the sound-emitting device emits an alarm and/or the light emitting means emits a light, e.g. a red light, if the electronically readable data does not match. This ensures that the right blood unit has been selected for the patient. It is well understood in the art that blood should be refrigerated, i.e. at a temperature of approximately 4⁰C, and should not be out of refrigeration for longer than an acceptable time, e.g. not more than 4 to 5 hours, to minimise bacterial growth. It is therefore important that blood should be transfused to a patient as soon as possible after removal from refrigeration.

Thus in one embodiment, the locking mechanism also comprises one or more sensors, such as a sensor for temperature, humidity, shock/vibration, light, radiation or time. The one or more sensors can be used to calculate the time that the blood has been outside of refrigeration. The sensor may then compare this calculated time with certain allowable time limits. If the blood unit has been outside of refrigeration for more than the allowable time limit, the locking mechanism cannot be unlocked by the unlocking signal or alternatively the locking mechanism may automatically lock itself - preventing the further transfusion of blood. In a further embodiment, the sound-emitting device emits an alarm and/or the light emitting means emits a light, e.g. a red light, if the blood unit has been outside of refrigeration for more than the allowable time limit.

In a further aspect of the invention there is provided a kit for ensuring transfusion of blood to the correct patient, wherein the kit comprises: a first identification tag as defined hereinbefore; a second identification tag as defined hereinbefore; and a locking mechanism as defined hereinbefore.

In yet a further aspect of the invention there is provided a kit for ensuring transfusion of blood to the correct patient, wherein the kit comprises: a locking mechanism as defined hereinbefore; and a patient identification device as defined hereinbefore. The invention will now be described, by way of example only, with reference to the accompanying drawings of which:

Figures 1 to 5 show an embodiment of the invention.

Figure 1 shows a patient identification device 100 comprising a wristband 110 that is detachably attached to a blood tube 120. The wristband 110 is fixedly attached to a second RFID tag 140, which encodes an identifying number, and the blood tube 120 is fixedly attached to a first RFID tag 130, which encodes the same identifying number as the second RFID tag 140.

In alternative embodiments, the first RFID tag 130 may be detachably attached to the wristband 110. In further embodiments, not shown, the patient identification device 100 may be provided with alternative types of identification tag.

The patient identification device 100 comprising the assembly of blood tube 120 and wristband 110 is supplied from the manufacturer with matching first 130 and second RFID tags 140 that are ready for use by the phlebotomist.

When a patient is identified as requiring a blood transfusion, a new sample of blood may be drawn, even if the blood group is already known to the laboratory. As soon as the blood is obtained from the patient, the blood tube 120 and wristband 110 are labelled together according to standard hospital procedure.

Figure 2 shows the wristband 110, with the second RFID tag attached 140, detached from the blood tube 120, and the wristband 110 applied to the patient

150 where it may remain for several days. The blood tube 120, with first RFID tag 130 attached and filled with patient blood 160, is transported to the laboratory where standard procedures are undertaken to identify the patient blood ABO and Rhesus groups.

When it is decided that a blood transfusion is required, a request which may be written or verbal, is made to the laboratory to provide the required number of units for transfusion. The laboratory technician uses standard laboratory procedure to select compatible blood transfusion units for the intended patient.

As shown in Figure 3, a clamp 170 is applied to each transfusion unit 180 and is sealed by an electrically actuated lock 190, which is programmed to be locked by the first RFID tag 130. Such programming can be achieved by using a remote control unit 200 with infrared command signalling. It will be appreciated that a person skilled in the art will readily know how to implement such an arrangement. It is possible to program several locks for the same intended patient, in the same manner, if more than one transfusion unit 180 is requested.

One programmed lock 190 with clamp 170 is applied to each transfusion unit 180, and then placed in the blood fridge awaiting collection. The one or more sealed transfusion units 180 are then collected from the fridge and transported to the patient area, where the identification of blood transfusion units and intended recipient are checked by suitably qualified and trained hospital staff according to standard hospital procedure.

As shown in Figure 4, the blood transfusion unit 180 must be detached from the clamp 170 before the blood can be accessed. This can only be achieved by bringing the lock 190 into close proximity with the second identification tag 140, which is fixedly attached to the patient 150 via the wrist band 110. This unlocks the lock 190, opens the clamp 170 and releases the correct unit for transfusion at the bedside of the correct patient 150 - thus ensuring that the correct unit of blood is transfused to the correct recipient. After the blood transfusion unit 180 has been detached from the clamp 170 and lock 190, it is connected to the patient 150 as shown in Figure 5.

In this embodiment of the invention, the blood locks are returned to the laboratory, where they can be reprogrammed and used repeatedly for further transfusions episodes and the pairs of identification tags are used only once per transfusion episode and then discarded.

The majority of errors which lead to accidental transfusion of incorrect blood result from misidentification of the patient at the time of initial blood sampling, at the time of collection of blood from the blood fridge, or at the time of administration of blood. It will be appreciated by those expert in the art of transfusion practice, that the present invention adds an additional unique identification parameter to existing established transfusion checking procedures, and therefore does not interfere with or detract from existing procedures. The critical identification time points are when the blood sample is withdrawn from the patient and secondly when donor blood is to be administered to the patient, and this invention ensures that an identification loop is established that ensures that the same patient is identified at the beginning and the end of the process - and that the procedure is physically secured by a uniquely programmed lock.

Claims

1. A method for ensuring transfusion of blood to the correct patient, wherein the method comprises: (a) providing the patient with a first identification tag and a second identification tag;

(b) allocating a blood bag to the patient containing the type of blood required by said patient;

(c) directly attaching a locking mechanism to an outlet of the blood bag; (d) locking the locking mechanism with a signal generated by the first identification tag; and

2. The method of claim 1 wherein the first identification tag comprises:

(i) electronically readable data, which may be used to generate a locking signal; and

3. The method of claim 1 wherein the second identification tag comprises:

(i) electronically readable data, which may be used to generate an unlocking signal; and

4. The method of claim 2 or claim 3 wherein the electronically readable data comprises patient identification information selected from one or more of the patient ID number, surname, forename, date of birth, gender, diagnosis and blood requirements, e.g. blood type (A, B, O) , rhesus factor and other requirements, such as antibody negative, leucocyte depleted, irradiated, CMV negative blood and/or a unique number for the specific transfusion episode.

5. The method as defined in any preceding claims wherein the first identification tag and the second identification tag may be a Radio Frequency

Identification (RFID) tag, a magnetic swipe card, a password system, a biometric device (such as a retinal scanner, thumbprint reader, voice identification unit, or the like) , or a linear or two-dimensional barcode using any one of many common barcode formats with a bar code reader.

6. The method as defined in claim 5 wherein the first identification tag is an RFID tag, and the second identification tag is an RFID tag.

7. The method as defined in claim 6 wherein the first identification tag and/or the second identification tag are passive RFID tags.

8. The method as defined in any preceding claims wherein the code on the first identification tag is identical to the code on the second identification tag.

9. The method as defined in any preceding claims which additionally comprises collecting a blood sample from said patient and testing said blood sample to determine the type of blood required by the patient prior to step (b) .

10. The method as defined in any preceding claims wherein the blood bag has a third identification tag, containing or encoding the blood group identification data of the transfusion unit.

11. The method as defined in any preceding claims wherein the locking mechanism comprises an electrically actuated lock.

12. The method as defined in claim 11 wherein the locking mechanism comprises a sound-emitting device, for example, a speaker, a piezzo buzzer or the like or a light emitting device, such as one or more LEDs.

13. The method as defined in claim 12 wherein the sound-emitting device emits an alarm and/or the light emitting means emits a light, e.g. a red light, if the electronically readable data does not match.

14. The method as defined in any of claims 11 to 13 wherein the locking mechanism additionally comprises one or more sensors, such as a sensor for temperature, humidity, shock/ vibration, light, radiation or time.

15. The method as defined in any of claims 11 to 14 wherein the locking mechanism additionally comprises an electronic printed circuit board (PCB) , which is configured to communicate with the first and second identification tags via an antenna.

16. The method as defined in claim 15 wherein the PCB is configured to read the identification signal generated by the first identification tag, restrict the actuation of the locking mechanism to the identification signal of the first and second identification tags for one transfusion episode only.

17. The method as defined in any of claims 11 to 16 wherein the locking mechanism comprises clamping means which, upon actuation, are configured to obstruct the outlet tube(s) of the blood bag and prevent transfusion.

18. A patient identification device, comprising a wristband, which is fixedly attached to the second identification tag as defined in claim 1.

19. The device as defined in claim 18 wherein the patient identification device additionally comprises the first identification tag as defined in claim 1 wherein the first identification tag is detachably attached to the wristband.

20. The device as defined in claim 18 or claim 19 which additionally comprises a blood sample receptacle.

21. The device as defined in claim 20 wherein a first identification tag is fixedly attached to the blood sample receptacle.

22. A kit for ensuring transfusion of blood to the correct patient, wherein the kit comprises: a first identification tag as defined in claim 1; a second identification tag as defined in claim 1; and a locking mechanism as defined in any of claims 1 or 11 to 17.

23. A kit for ensuring transfusion of blood to the correct patient, wherein the kit comprises: a locking mechanism as defined in any of claims 1 or 11 to 17; and a patient identification device as defined in any of claims 18 to 21.