WO2004098410A1

WO2004098410A1 - Blood collection devices and methods

Info

Publication number: WO2004098410A1
Application number: PCT/GB2004/001901
Authority: WO
Inventors: Edward Adamowicz
Original assignee: Cinimod (Ip) Limited
Priority date: 2003-05-03
Filing date: 2004-05-04
Publication date: 2004-11-18
Also published as: EP1620011A1; GB0310297D0

Abstract

A blood collection device (20) for collecting a blood sample from a foetal scalp comprises a blood collector preferably in the form of a capillary tube (22) and a cutting member (24) for incising the foetal scalp which is movable between a primed condition and a cutting condition. The blood collection device (20) includes a biasing arrangement (26) to urge the cutting member (24) from the primed condition to the cutting condition, the capillary tube (22) being arranged to collect blood from the foetal scalp when the cutting member (24) is moved to the cutting condition. The biasing arrangement (26) is preferably also operable to urge the cutting member (24) from the cutting condition to a retracted condition. The device (20) preferably also includes a blood detection system for detecting the présence of blood in the capillary tube (22).

Description

Blood Collection Devices and Methods

The present invention relates to blood collection devices, and particularly but not exclusively to blood collection devices for collecting blood from a foetal scalp. The invention also relates to methods of collecting blood, in particular but not exclusively from a foetal scalp.

Measurement of oxygen supply to a foetus can be necessary where there is concern that the foetus is not receiving adequate oxygen. This may be achieved by collecting blood from the foetal scalp and carrying out an analysis of

^> the collected blood. Collection of blood is usually achieved by using a suitable blood collection device to incise the foetal scalp and collect blood from the incision.

According to a first aspect of the present invention, there is provided a blood collection device comprising a blood collector, a cutting member movable between a primed condition and a cutting condition, and a biasing arrangement to urge the cutting member from the primed condition to the cutting condition, the blood collector being arranged to collect blood when the cutting member is moved to the cutting condition.

The biasing arrangement may comprise a biasing member to urge the cutting member from the primed condition to the cutting condition. The biasing member may be in a biasing state when the cutting member is in the primed condition. The biasing member may be a compression spring. The biasing member may be compressed when the cutting member is in the primed condition.

The blood collection device may include a retaining arrangement for retaining the cutting member in the primed condition. The retaining arrangement may be movable from a retaining condition in which movement of the cutting member from the primed condition to the cutting condition is prevented, to a release condition in which movement of the cutting member from the primed condition to the cutting condition is enabled. The cutting member may be movable from the cutting condition to a retracted condition. The biasing arrangement may urge the cutting member from the cutting condition to the retracted condition. The biasing arrangement may comprise a further biasing member to urge the cutting member from the cutting condition to the retracted condition. The further biasing member may be in a biasing state when the cutting member is in the cutting condition. The further biasing member may be a compression spring. The further biasing member may be compressed when the cutting member is in the cutting condition.

The cutting member may be slidably mounted on the blood collector for movement between the primed condition and the cutting condition. The cutting member may be slidably movable to the retracted condition. The cutting member may have first and second ends and may be substantially cylindrical for slidable mounting on the blood collector.

The cutting member may include a reaction arrangement to provide a reaction against the biasing arrangement. The reaction arrangement may comprise first and second reaction means. The first reaction means may provide a reaction for the first mentioned . biasing member, and the second reaction means may provide a reaction for the further biasing member. The first reaction means may be located substantially at the second end of the cutting member and the second reaction means may be located substantially at the first end of the cutting member. The first and second reaction means may each respectively comprise a flange. Each flange may include a reaction surface.

Cutting means may be provided at the second end of the cutting member for incising skin. The cutting means may comprise a blade, or may comprise a plurality of blades spaced circumferentially around the second end. The cutting means may comprise three blades equispaced circumferentially around the second end. The or each blade may be tapered to provide a sharp point. The cutting means may comprise plastics material.

The blood collection device may include an elongate housing having first and second ends. A longitudinal axis may extend between said ends. A bore may be defined longitudinally through the housing. The first end may include holding means for holding the blood collector, which holding means may comprise a resilient material which may deform to receive a portion of the blood collector. The blood collector may have first and second ends and the resilient material- may receive the first end and may deform therearound to hold the blood collector.

The second end of the blood collector may extend from the second end of the housing. The second end of the blood collector may be substantially flush with the cutting means when the cutting member is in the retracted condition.

The blood collector may comprise a blood conduit, which conduit may be substantially elongate. The blood collector may comprise a tube. The blood collector may be a capillary tube.

The retaining arrangement may be mounted in the bore of the housing, and may be mounted towards the second end thereof. The retaining arrangement may include a reaction member which may be located between the first and second reaction means of the cutting member, and preferably immovably located therebetween. The first mentioned biasing member may be located between the first reaction means and the reaction member. Said further biasing member may be located between the second reaction means and the reaction member. The reaction member may include a first reaction surface for abutting the biasing member, and may include a second reaction surface for abutting the further biasing member. The reaction member may be a flange.

When the cutting member is in the primed condition, the first mentioned biasing member may be in a biasing state between the first reaction means and the reaction member, and said further biasing member may be in a relaxed state. When the cutting member is in the cutting condition, said further biasing member may be in a biasing state between the second reaction means and the reaction member, and the first mentioned biasing member may be in a relaxed state. When the cutting member is in the retracted condition, the biasing member and further biasing member may both be in a substantially relaxed state. The biasing member and further biasing member may be compressed when in the biasing state, and may be substantially uncompressed when in the relaxed state.

The retaining arrangement may comprise at least one resilient member which, when the retaining arrangement is in the retaining condition, may cooperatively engage the cutting member to retain the cutting member in the primed condition. The retaining arrangement may comprise two resilient members. The or each resilient member may extend from the reaction member in a direction substantially parallel to the longitudinal axis of the housing and preferably away from the second end of the housing towards the first end. The or each resilient member may extend substantially alongside the further biasing member and terminate at an unconstrained end. The unconstrained end may co-operatively engage the second reaction means when the retaining arrangement is in the retaining condition to retain the cutting member in the primed condition. The co- operative engagement may be by abutment. The or each resilient member may be a leaf spring.

The device may include a trigger arrangement movable between a first condition in which it holds the retaining arrangement in the retaining condition and a second condition for allowing movement of the retaining arrangement from the retaining condition to the release condition. The trigger arrangement may be slidably mounted on the housing. The trigger arrangement may include a skin engaging portion, which may be annular. The skin engaging portion may be concentric with the bore of the housing.

The trigger arrangement may include holding means for holding the retaining arrangement in the retaining condition. The holding means may engage the or each resilient member and may urge the or each resilient member into cooperative engagement with the cutting member when the retaining arrangement is in the retaining condition. The holding means may comprise one or more arms. The or each arm may include a protuberance for engaging the or each resilient member. The or each protuberance may extend inwardly towards the bore of the housing. The or each arm may extend from the skin engaging portion. The housing may include one or more channels for receiving the or each arm. The or each channel may extend from the second end of the housing longitudinally along its outer surface and may slidably receive the or each arm. The or each channel may include a slot extending from the outer surface of the housing into the bore for receiving a corresponding protuberance on the or each arm. The or each protuberance may be movable longitudinally within the or each corresponding slot.

The device may include a wiping arrangement for cleaning skin prior to collecting blood. The wiping arrangement may be provided on the trigger arrangement. The wiping arrangement may be provided on the skin engaging portion. The wiping arrangement may be automatically actuable. The trigger arrangement may include wiper actuating means to activate the wiping arrangement. The wiping arrangement may be actuated by movement of the trigger arrangement from the first condition to the second condition. The wiping arrangement may provide a seal between the device and the skin to enable collection of uncontaminated blood by the blood collector when the cutting member is in the cutting condition.

The wiping arrangement may comprise a wiping member, which may be annular. The wiping member may comprise a resilient material which may comprise a region of weakness. The wiping member may include wiping projections. The wiping arrangement may include a mounting member for mounting the wiping member and the trigger arrangement. Retaining means may be provided on the wiping member to retain the wiping member on the mounting member under tension. The retaining means may comprise co-operating formations on the wiping member and the trigger arrangement, wherein the formations co-operate to retain the wiping member on the trigger arrangement. The co-operating formations may comprise a projecting formation and a recess formations on the wiping member and the trigger arrangement. In one embodiment, the projection formation may be provided on the wiping member, and the recess formation may be defined on the trigger arrangement. Where the wiping member is of an annular configuration, the projecting formation may comprise at least one annular bead, and the recess formation may comprise at least one annular recess to receive the annular bead. The wiping member may comprise a plastics or rubber material. The wiper activating means may co-operate with the region of weakness on the wiping member to activate the wiping arrangement. The wiper activator means may comprise a cutting projection on the trigger arrangement.

The device may include a handle. The handle may be removably mountable on the first end of the housing. The device may comprise plastics material, and may be formed by injection moulding.

The device may be arranged to collect blood from a foetal scalp.

The device may include a blood detection system for detecting the presence of blood in the blood collector. The detection system may detect the presence of a predetermined amount of blood in the blood collector, and may provide for detection of the presence of blood at the first end of the blood collector. The detection system may include an indicator for indicating the presence of blood in the blood collector, which indicator may comprise a light- emitting diode (LED).

The blood detection system may comprise an electromagnetic radiation emission/detection arrangement, which arrangement may comprise an emitter for emitting electromagnetic radiation on one side of the blood collector and a receiver for receiving emitted electromagnetic radiation on an opposite side of the blood collector. The receiver may detect a variation in the amount of emitted electromagnetic radiation transmitted through the blood collector due to presence of blood therein.

The emission/detection arrangement may comprise a further receiver for receiving reflected electromagnetic radiation. The further receiver may detect a variation in the amount of reflected electromagnetic radiation due to presence of blood in the blood collector. The further receiver may receive reflected electromagnetic radiation at substantially the same location as electromagnetic radiation is emitted by the emitter.

One or more of the emitter, receiver and further receiver may be located adjacent the blood collector, and may be provided on the blood collector holding means. Alternatively, one or more of the emitter, receiver and further receiver may be located remote from the blood collector, transmission means being provided for transmitting electromagnetic radiation between the emitter, receiver, further receiver and the blood collector. The transmission means may comprise a light transmitting material, which material may comprise optical fibres.

The electromagnetic radiation emission/detection arrangement may be arranged to emit and detect infrared electromagnetic radiation, and preferably infrared light.

The blood detection system may alternatively comprise a detection arrangement for detecting a change of capacitance due to presence of blood in the blood collector. The detection arrangement may comprise a coil positioned around the blood collector and having a self-capacitance, the self-capacitance increasing when blood is present in the blood collector. The detection system may alternatively comprise two substantially annular metallic members spaced longitudinally along the blood collector and having therebetween a capacitance. The capacitance may increase due to presence of blood in the blood collector in the space defined between the metallic members.

As a further alternative, the blood detection system may comprise a resistance wire extending into the bore of the blood collector, electrical resistance between the wire and the skin decreasing, in use, when blood is present in the blood collector between skin and the wire.

As a yet further alternative, the blood detection system may comprise a piezo-electric transducer for oscillating the blood collector and measuring a decrease in the resonant frequency of the blood collector due to the presence of blood therein. According to a second aspect of the present invention, there is provided a blood detection system for detecting presence of blood in a blood collector of a blood collection device according to the first aspect of the present invention.

According to a third aspect of the present invention, there is provided a method of operating a blood collection device including a blood collector and a cutting member movable between a primed condition and a cutting condition, the method comprising locating the blood collection device adjacent skin, moving, under spring bias, the cutting member from the primed condition to the cutting condition to incise the skin, and collecting blood from the incision in the blood collector.

According to a fourth aspect of the present invention, there is provided a method of collecting blood comprising providing a blood collection device including a blood collector and a cutting member movable between a primed condition and a cutting condition, locating the cutting member adjacent skin, moving, under spring bias, the cutting member from the primed condition to the cutting condition to incise the skin, and collecting blood from the incision in the blood collector.

The method may comprise the step of moving the cutting member, under spring bias, from the cutting condition to a retracted condition. The method may include the step of detecting the presence of blood in the blood collector. The method may include the step of locating the blood collection device adjacent a foetal scalp and collecting blood from the foetal scalp. The blood collection device may be according to the first aspect of the present invention.

According to a fifth aspect of the present invention, there is provided a blood collection device comprising a housing, a cutting member movable between a retracted condition and a cutting condition, a blood collector for collecting blood when the cutting member is moved to the cutting condition, and a blood detection system for detecting the presence of blood in the blood collector. The detection system may detect the presence of a predetermined amount of blood in the blood collector. The blood collector may have first and second ends, the detection system providing for detection of the presence of blood at the first end thereof. The detection system may include an indicator for indicating the presence of blood in the blood collector, which indicator may comprise a light- emitting diode (LED).

The electromagnetic radiation emission/detection arrangement may comprise a further receiver for receiving reflected electromagnetic radiation. The further receiver may detect a variation in the amount of reflected electromagnetic radiation due to presence of blood in the blood collector. The further receiver may receive reflected electromagnetic radiation at substantially the same location as electromagnetic radiation is emitted by the emitter.

One or more of the emitter, receiver and further receiver may be located adjacent the blood collector. The blood collection device may include a blood collector holding means, one or more of the emitter, receiver and further receiver being provided on the holding means. Alternatively, one or more of the emitter, receiver and further receiver may be located remote from the blood collector, transmission means being provided for transmitting electromagnetic radiation between the emitter, receiver, further receiver and the blood collector. The transmission means may comprise a light transmitting material, which material may comprise optical fibres. The electromagnetic radiation emission/detection arrangement may be arranged to emit and detect infrared electromagnetic radiation, and preferably infrared light.

As a yet further alternative, the blood detection system may comprise a piezo-electric transducer for oscillating the blood collector and measuring a decrease in the resonant frequency of the blood collector due to presence of blood therein.

Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which:-

Fig. 1 is a diagrammatic side view of a blood collection device in a primed condition;

Fig. 2 is a sectional view along line A-A of Fig. 1 ;

Fig. 3 is a diagrammatic side view of the device in a cutting condition; Fig. 4 is a sectional view along line B-B of Fig. 3;

Fig. 5 is a diagrammatic side view of the device in a retracted condition;

Fig. 6 is a sectional view along line C-C of Fig. 5;

Fig. 7a is a diagrammatic exploded view of the device;

Fig. 7b is a detailed view of a wiping arrangement of the device;

Fig. 8 is a diagrammatic side view of the device including a handle;

Fig. 9 is a sectional view along line D-D of Fig. 8;

Fig. 10 is an enlarged diagrammatic side view of the handle; and

Fig. 11 is a sectional view along line E-E of Fig. 10.

Referring to Figs. 1 to 6, there is shown generally a blood collection device 20 comprising a blood collector in the form of a capillary tube 22 and a cutting member 24 movable between a primed condition and a cutting condition. The device 20 includes a biasing arrangement 26 to urge the cutting member 24 from the primed condition to the cutting condition, the blood collector being arranged to collect blood when the cutting member 24 is moved to the cutting condition.

In more detail, the blood collection device 20 includes an elongate housing

28 having first and second ends 30, 32, a longitudinal axis extending between the first and second ends 30, 32 and a bore 34 defined longitudinally through the housing 28. The housing 28 is substantially cylindrical and has an outer surface 36. The first end 30 of the housing 28 is closed to prevent access to the bore 34.

The second end 32 of the housing 28 includes channels 40 extending along the outer surface 36. The channels 40, the purpose of which will be described hereinafter, extend longitudinally along the outer surface 36 partway along the housing 28 from the second end 32 towards the first end 30, and are located at substantially diametrically opposite positions on the outer surface 36 of the housing 28. The channels 40 each terminate at a slot 42 which extends from the outer surface 36 of the housing 28 into the bore 34, thereby providing access from the outer surface 36 to the bore 34.

Blood collector holding means 44 are provided at the first end 30 of the housing 28. The holding means 44 comprise a resilient material, such as rubber, which acts both to seal the first end 30 of the housing 28 and to hold a first end 46 of the capillary tube 22. The resilient material of the holding means 44 is resiliency deformable around the first end 46 of the capillary tube 22 to securely hold the capillary tube 22 in position in the housing 28.

The capillary tube 22 is elongate and has first and second ends 46, 50. The second end 50 projects from the bore 34 of the housing 28 at its second end 32.

The cutting member 24 is substantially cylindrical and is slidably mounted on the capillary tube 22 for movement between the primed, cutting, and retracted conditions. The cutting member 24 has first and second ends 52, 54, and at its second end 54 includes a first reaction means in the form of a flange 58 and at its first end 52 includes a second reaction means in the form of a flange 56. As best seen in Fig. 7, the flange 56 extends in a substantially continuous manner around the first end 52 of the cutting member 24 whilst the flange 58 comprises four protrusions 60 which are circumferentially equispaced around the second end 54.

Cutting means 62 are provided at the second end 54 of the cutting member 24. The cutting means 62 are formed of plastics material and include three blades 64 circumferentially equispaced around the second end 54 of the cutting member 24. The cutting means 62 include a projection 66 which is receivable within a corresponding recess 68 defined by the flange 58 at the second end 54 of the cutting member 24. The blades 64, which are formed of plastics material, are tapered in the longitudinal direction of the housing 28 to provide a sharp point 70.

A retaining arrangement 12 is fixedly mounted in the bore 34 of the housing and is movable from a retaining condition in which it prevents movement of the cutting member 24 from the primed condition to the cutting condition, to a release condition in which it permits movement of the cutting member 24 from the primed condition to the cutting condition. The retaining arrangement 72 includes a reaction member in the form of a flange 74. The flange 74 is substantially circular and includes first and second reaction surfaces 76, 78 for abutting the biasing members. The flange 74 includes an aperture 79 which enables the flange 74 to be located around the cutting member 24. The retaining arrangement 72 is located in the housing 28 such that the first reaction surface 76 faces the flange 58 and the second reaction surface 78 faces the flange 56.

The retaining arrangement 72 includes resilient members in the form of leaf springs 80 which extend from the flange 74 on diametrically opposite sides thereof. Each leaf spring 80 extends from the flange 74 substantially parallel to the longitudinal axis of the housing 28 towards the first end 30 of the housing 28. Each leaf spring 80 terminates at an unconstrained end 82 which, when the cutting member 24 is in the primed condition, cooperatively engages by abutment the flange 56.

The biasing arrangement 26 comprises a biasing member in the form of an actuating compression spring 84 for urging the cutting member 24 to slide on the capillary tube 22 from the primed condition to the cutting condition. The biasing arrangement 26 includes a further biasing member in the form of a retracting compression spring 86 which urges the cutting member 24 to slide in an opposite direction on the capillary tube 22 from the cutting condition to a retracted condition. The actuating compression spring 84 is located on the cutting member 24 between the flange 58 and the first reaction surface 76. In a similar manner, the retracting compression spring 86 is located on the cutting member 24 between the flange 56 and the second reaction surface 78. A trigger arrangement 88 is slidably mounted on the housing 28 for movement between a first condition in which it holds the retaining arrangement 72 in the retaining condition, and a second condition in which is permits movement of the retaining arrangement 72 from the retaining condition to the release condition. In more detail, the trigger arrangement 88 includes an annular skin engaging portion 90 having an aperture 92 arranged to allow passage therethrough of the cutting means 62 and the second end 50 of the capillary tube 22. Arms 94, which are positioned diametrically opposite each other, extend from the skin engaging portion 90 in a direction substantially parallel to the longitudinal axis of the housing 28. The arms 94 each include a protuberance 96 at their free end with the protuberances 96 projecting inwardly towards each other. Each arm 94 is slidably received in a corresponding channel 40 in the housing 28 and each protuberance 96 received within a corresponding slot 42 at the end of a respective channel 40. Each protuberance 96 accordingly projects into the bore 34 of the housing 28 to engage a corresponding leaf spring 80 when the retaining arrangement 72 is in the retaining condition. The location of the protuberances 96 in the slots 42 provides a limited range of sliding movement of the trigger arrangement 88 on the housing 28 and thereby prevents separation of the trigger arrangement 88 from the housing 28.

A retaining member in the form of a retaining cap 98 is provided at the second end 32 of the housing 28 to retain the various components, and in particular the retaining arrangement 72, in the bore 34 of the housing 28. The retaining cap 98 includes an aperture 100 through which the cutting means 62 and the second end 50 of the capillary tube 22 may project. The cap 98 includes a substantially circular extension 102 receivable within the bore 34 of the housing 28 at the second end 32 and also includes a flange 104 for abutting the housing 28. The flange 104 includes recesses 106 which act as continuations to the channels 40 to enable the arms 94 to be slidably received within the channels 40. The extension 102 has an external diameter which is slightly larger than the internal diameter of the bore 34 so that the cap 98 is retained in the bore 34 by friction fit. Referring to Fig. 7b, a wiping arrangement 108 is also provided on the skin engaging portion 90 for cleaning skin prior to commencement of blood collection. The wiping arrangement 108 includes an annular mounting member 150 formed of moulded plastics material and defining a recess 151 to receive the end of the trigger arrangement, by means of which the wiping arrangement 108 can be located on the trigger arrangement 88. A resilient plastics annular wiping member 152 is located on the mounting member 150 initially under tension. Retaining means in the form of projecting formations or beads 154 are provided at each end of the wiping member 152 to retain it in position in corresponding co- operating recess formations 155 under tension on the mounting member 150. The wiping member 152 includes wiping projections 156 which clean the skin upon actuation of the wiping arrangement 108 and which also provide a cushion between the skin and the trigger arrangement 88.

The wiping member 152 includes an annular region of weakness 158 which is provided by a thinner layer of material on the wiping member 152. A wiper activating means in the form of a sharp projection 160 is provided on the trigger arrangement 88 to cut the wiping member 152 at the region of weakness 158. When the projection 160 cuts the wiping member 152 in use, the tension force in the member 152 causes it to move outwards whilst being retained at its outermost edge 162. The wiping projections or blades 156 thus wipe the skin and remove contamination therefrom. The wiping arrangement 108, in addition to removing contamination from the surface of the skin, provides a seal or preclusion membrane between the device 20 and skin to ensure that blood does not become contaminated during collection whilst the cutting member 24 is in the cutting condition.

Referring again in particular to Figs. 1 to 6, the device 20 is operable between a primed condition in which the cutting member 24 is located within the bore 34 of the housing 28, a cutting condition in which the cutting member 24 extends from the second end 32 of the housing 28 to incise skin, and a retracted condition in which the cutting member 24 is located within the bore 34 of the housing 28. Referring to Fig. 2, the device 20 is initially in the primed condition in which the cutting member 24 is located on the capillary tube 22 in a position such that the actuating compression spring 84 is compressed between the flange 58 and the first reaction surface 76. In the primed condition, the actuating compression spring 84 is in a compressed state for urging the cutting member 24 to slide along the capillary tube 22 in a direction away from the first end 30 towards the second end 32 of the housing 28. However, in the primed condition shown in Fig. 2, the retaining arrangement 72 is in the retaining condition such that the unconstrained ends 82 of the leaf springs 80 cooperatively engage by abutment the flange 56. This prevents the cutting member 24 from being urged by the actuating compression spring 84 to slide along the capillary tube 22. The leaf springs 80 are maintained in engagement with the flange 56 by the protuberances 96 of the trigger arrangement 88.

In order to actuate the blood collection device 20 to enable collection of blood from a foetal scalp, the skin engaging portion 90 of the trigger arrangement 88 is pressed against the foetal scalp to cause the arms 94 to slide in the channels 40 in a direction away from the second end 32 towards the first end 30 of the housing 28. This causes simultaneous movement of the protuberances 96 within the corresponding slots 42 such that the protuberances 96 are moved out of engagement with the leaf springs 80. The inherent resilience of the leaf springs 80 causes them to move outwardly towards an inner surface, of the bore 34 and out of engagement with the flange 56.

The actuating compression spring 84 then urges the cutting member 24 to slide on the capillary tube 22 to the position shown in Fig. 4 in which the cutting means 62 project from the second end 32 of the housing 28 and through the aperture 92 such that the blades 64 incise the foetal scalp.

As the trigger arrangement 88 is pressed against the scalp projection 160 cuts and ruptures the wiping member 152 causing it to move outwardly under tension and causing the wiping projections 156 to wipe the scalp and remove contamination therefrom. Once ruptured, the wiping member 152 also provides a seal or preclusion membrane between the skin engaging portion 90 and the scalp to prevent contamination of blood during collection.

When in the cutting condition, the second end 50 of the capillary tube 22 is located adjacent the surface of the scalp and provides for optimal collection of blood by capillary action. The second end 50 of the capillary tube 22 does not come into direct contact with the foetal scalp. As best seen in Fig. 4, when the cutting member 24 is in the cutting condition, the retracting compression spring 86 is compressed between the flange 56 and the second reaction surface 78. Due to the fact that the retracting compression spring 86 is in a compressed state, it urges the cutting member 24 to slide on the capillary tube 22 from the cutting condition in a direction towards the first end 30 of the housing 28 to the retracted condition shown in Fig. 6 in which the cutting means 62 is located substantially within the housing 28, and in particular within the aperture 92 of the trigger arrangement 88. In the retracted condition, both the actuating compression spring 84 and the retracting compression spring 82 are in a relaxed state and remain in abutment with the flanges 56, 58 and the first and second reaction surfaces 76, 78 to hold the cutting member 24 in the retracted condition. The springs 84, 86 may be compressed by a small amount when the cutting member 24 is in the retracted condition.

As will be appreciated, due to the arrangement of the blood collection device 20 and due to the provision of the actuating and retracting compression springs 84, 86, when the trigger arrangement 88 is actuated to release the retaining arrangement 72, the movement of the cutting member 24 from the primed condition to the cutting condition and then to the retracted condition takes place in a very short space of time. The cutting member 24 effectively punches the foetal scalp to cause an incision and the cutting means 62 do not remain embedded within the foetal scalp for any significant period of time. Once the device 20 has been actuated and an incision made in the scalp, the device 20 is retained against the scalp such that the skin engaging portion 90 remains in contact with the scalp to enable blood emanating from the incision to be collected in the capillary tube 22 by capillary action. When a sufficient amount of blood has been collected in the capillary tube 22, the device 20 is moved out of contact with the foetal scalp.

In order for a user to know when sufficient blood has been collected in the capillary tube 22, the device 20 is, in a preferred embodiment, provided with a blood detection system for detecting the presence of blood in the capillary tube 22.

Referring in particular to Figs. 8 to 11 , the device 20 includes a handle 1 0 which is mountable on the housing 28 by a bayonet fitting 122 in which a pin 124 is locatable in a corresponding slot 126. The handle 120 houses a number of components of the blood detection system, and includes a light-emitting diode (LED) 128 which illuminates or changes colour to indicate to a user that sufficient blood has been collected in the capillary tube 22. The LED 128 is visible through the transparent plastics material of the housing 28.

In more detail, the blood detection system comprises an emission/detection arrangement including an infrared emitter 130 located on one side of the capillary tube 22 and an infrared receiver 132 located on an opposite side of the capillary tube 22 for receiving infrared light from the emitter 130. The receiver 132 detects the presence of blood 134 in the capillary tube 22 by detecting a variation in the amount of emitted infrared light. The user is then alerted to the presence of blood 134 in the capillary tube 22 by illumination or a change in colour of the LED 128.

A further infrared receiver 136 is also provided for receiving reflected infrared light. The further receiver 136 is arranged to receive reflected infra red light at substantially the same location as infra red light is emitted by the emitter 130.

The handle 120 includes a printed circuit board (PCB) 138 on one side of which the LED 128 is mounted. A power supply means in the form of one or more batteries 142 is located in the handle 120 and retained therein by a closure 144 which is threadably mounted on the handle 120. The batteries 142 are in contact with the PCB 138 and provide power to the components of the blood detection system including the emitter 130, receiver 132 and further receiver 136 and the LED 128.

There is thus provided a blood collection device 20 which is both easy to use and permits efficient collection of blood from a foetal scalp. The biasing arrangement 26 provides for automatic plunge of the cutting means 62 into the foetal scalp to a specific and controlled depth to create an incision. The biasing arrangement 26 moreover provides for automatic retraction of the cutting means 62 into the housing 28 which ensures that a user cannot accidentally cut or injure themselves on an exposed blade 64. The fixed and precise location of the capillary tube 22, by the holding means 44, adjacent the foetal scalp provides for optimum collection of blood once an incision has been made in the scalp.

The trigger arrangement 88 ensures that the device is easy to use and provides for single handed use. This enables a user to simply press the device 20 against a foetal scalp and retain it in contact with the scalp until the LED 128 illuminates or changes colour. This obviates difficulties associated with prior blood collection devices of having to visually identify when sufficient blood has been collected in the capillary tube 22. This is particularly difficult since it is not possible when collecting blood using such a device to view the capillary tube 22 from the side.

The wiping arrangement 108 also provides significant advantages over the prior art in that it is automatically actuated when the cutting member 28 is moved from the primed condition to the cutting condition. The wiping arrangement 108 minimises and excludes contamination from the interface between the skin engaging portion 90 and the foetal scalp and also once actuated provides a seal or preclusion membrane between the device 20 and scalp to improve the likelihood of obtaining an uncontaminated blood sample.

The provision of multiple blades 64 which are of tapered section creates an incision in the scalp which enables greater blood flow than was previously obtainable, and also minimises bruising to the scalp. The tapered blades 64 are designed such that they initially pierce the skin and, as they penetrate the scalp, enlarge the incision to encourage bleeding.

Various modifications may be made without departing from the scope of the invention. For example, the housing 28, cutting member 24, retaining arrangement 72 and trigger arrangement 88 may have different configurations to those described with reference to the accompanying drawings. The cutting means 62 may comprise more or less than three blades 64. The blades 64 may be formed of a material other than plastics material, for example a suitable metal. The biasing member and further biasing member may be other than compression springs. The device 20 may comprise material other than plastics material. The blood detection system may comprise a detection arrangement which detects the presence of blood in the capillary tube 22 by means other than the emission and detection of electromagnetic radiation.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

1. A blood collection device comprising a blood collector, a cutting member movable between a primed condition and a cutting condition, and a biasing arrangement to urge the cutting member from the primed condition to the cutting condition, the blood collector being arranged to collect blood when the cutting member is moved to the cutting condition.

2. A device according to claim 1 , wherein the biasing arrangement comprises a biasing member to urge the cutting member from the primed condition to the cutting condition.

3. A device according to claim 2, wherein the biasing member is in a biasing state when the cutting member is in the primed condition.

4. A device according to claim 2 or claim 3, wherein the biasing member is a compression spring.

5. A device according to any of claims 2 to 4, wherein the biasing member is compressed when the cutting member is in the primed condition.

6. A device according to any preceding claim, wherein the blood collection device includes a retaining arrangement for retaining the cutting member in the primed condition.

7. A device according to claim 6, wherein the retaining arrangement is movable from a retaining condition in which movement of the cutting member from the primed condition to the cutting condition is prevented, to a release condition in which movement of the cutting member from the primed condition to the cutting condition is enabled.

8. A device according to any preceding claim, wherein the cutting member is movable from the cutting condition to a retracted condition.

9. A device according to claim 8, wherein the biasing arrangement is operable to urge the cutting member from the cutting condition to the retracted condition.

10. A device according to claim 8 or claim 9, wherein the biasing arrangement comprises a further biasing member to urge the cutting member from the cutting condition to the retracted condition.

11. A device according to claim 10, wherein the further biasing member is in a biasing state when the cutting member is in the cutting condition.

12. A device according to claim 10 or claim 11 , wherein the further biasing member is a compression spring.

13. A device according to any of claims 10 to 12, wherein the further biasing member is compressed when the cutting member is in the cutting condition.

14. A device according to any preceding claim, wherein the cutting member is slidably mounted on the blood collector for movement between the primed condition and the cutting condition.

15. A device according to any of claims 8 to 14, wherein the cutting member is slidably movable to the retracted condition.

16. A device according to claim 14 or claim 15, wherein the cutting member has first and second ends and is substantially cylindrical for slidable mounting on the blood collector.

17. A device according to any preceding claim, wherein the cutting member includes a reaction arrangement to provide a reaction against the biasing arrangement.

18. A device according to claim 17, wherein the reaction arrangement comprises first and second reaction means.

19. A device according to claim 18, wherein the first reaction means provides a reaction for the first mentioned biasing member, and the second reaction means provides a reaction for the further biasing member.

20. A device according to claim 18 or claim 19, wherein the first reaction means is located substantially at the second end of the cutting member and the second reaction means is located substantially at the first end of the cutting member.

21. A device according to any of claims 18 to 20, wherein the first and second reaction means each respectively comprise a flange.

22. A device according to claim 21 , wherein each flange includes a reaction surface.

23. A device according to claim 16 or any of claims 17 to 22 when dependent on claim 16, wherein cutting means are provided at the second end of the cutting member for incising skin.

24. A device according to claim 23, wherein the cutting means comprises a blade.

25. A device according to claim 23 or claim 24, wherein the cutting means comprises a plurality of blades spaced circumferentially around the second end.

26. A device according to claim 25, wherein the cutting means comprises three blades equispaced circumferentially around the second end.

27. A device according to any of claims 24 to 26, wherein the or each blade is tapered to provide a sharp point.

28. A device according to any of claims 23 to 27, wherein the cutting means comprises plastics material.

29. A device according to any preceding claim, wherein the blood collection device includes an elongate housing having first and second ends and a longitudinal axis extends between said ends.

30. A device according to claim 29, wherein a bore is defined longitudinally through the housing.

31. A device according to claim 29 or claim 30, wherein the first end includes holding means for holding the blood collector.

32. A device according to claim 31 , wherein the holding means comprises a resilient material which deforms to receive a portion of the blood collector.

33. A device according to claim 32, wherein the blood collector has first and second ends and the resilient material receives the first end and deforms therearound to hold the blood collector.

34. A device, according to claim 33, wherein the second end of the blood collector extends from the second end of the housing.

35. A device according to claim 34, wherein the second end of the blood collector is substantially flush with the cutting means when the cutting member is in the retracted condition.

36. A device according to any preceding claim, wherein the blood collector comprises a blood conduit which is substantially elongate.

37. A device according to any preceding claim, wherein the blood collector is a capillary tube.

38. A device according to any of claims 6 to 37, wherein the retaining arrangement is mounted in the bore of the housing towards the second end thereof.

39. A device according to claim 38, wherein the retaining arrangement includes a reaction member which is immovably located between the first and second reaction means of the cutting member.

40. A device according to claim 39, wherein the first mentioned biasing member is located between the first reaction means and the reaction member.

41. A device according to claim 39 or claim 40, wherein said further biasing member is located between the second reaction means and the reaction member.

42. A device according to any of claims 39 to 41 , wherein the reaction member includes a first reaction surface for abutting the biasing member and a second reaction surface or abutting the further biasing member.

43. A device according to any of claims 39 to 42, wherein the reaction member is a flange.

44. A device according to any of claims 39 to 43, wherein when the cutting member is in the primed condition, the first mentioned biasing member is in a biasing state between the first reaction means and the reaction member, and said further biasing member is in a relaxed state.

45. A device according to any of claim 39 to 44, wherein when the cutting member is in the cutting condition, said further biasing member is in a biasing state between the second reaction means and the reaction member, and the first mentioned biasing member is in a relaxed state.

46. A device according to any of claims 39 to 45, wherein when the cutting member is in the retracted condition, the biasing member and further biasing member are both in a substantially relaxed state.

47. A device according to any of claims 44 to 46, wherein the biasing member and further biasing member are compressed when in the biasing state, and are substantially uncompressed when in the relaxed state.

.5 48. A device according to- any of claims 6 to 47, wherein the retaining arrangement comprises at least one resilient member which, when the retaining arrangement is in the retaining condition, co-operatively engages the cutting member to retain the cutting member in the primed condition.

0 49. A device according to claim 48, wherein the retaining arrangement comprises two resilient members.

50. A device according to claim 48 or claim 49, wherein the or each resilient i,,, ., member extends from the reaction member in a direction substantially parallel to 5 the longitudinal axis of the housing and preferably away from the second end of the housing towards the first end.

51. A device according to any of claims 48 to 50, wherein the or each resilient member extends substantially alongside the further biasing member and 0 terminates at an unconstrained end.

52. A device according to claim 51 , wherein the unconstrained end cooperatively engages the second reaction means when the retaining arrangement is in the retaining condition to retain the cutting member in the primed condition. 5

53. A device according to claim 52, wherein the co-operative engagement is by abutment.

54. A device according to any of claims 48 to 53, wherein the or each resilient 0 member is a leaf spring.

55. A device according to any of claims 7 to 54, wherein the device includes a trigger arrangement movable between a first condition in which it holds the retaining arrangement in the retaining condition and a second condition for allowing movement of the retaining arrangement from the retaining condition to the release condition.

56. A device according to claim 55, wherein the trigger arrangement is slidably mounted on the housing.

57. A device according to claim 55 or claim 56, wherein the trigger arrangement includes a skin engaging portion which is preferably annular.

58. A device according to claim 57, wherein the skin engaging portion is concentric with the bore of the housing.

59. A device according to any of claims 55 to 58, wherein the trigger arrangement includes holding means for holding the retaining arrangement in the retaining condition.

60. A device according to claim 59, wherein the holding means engages the or each resilient member and urges the or each resilient member into co-operative engagement with the cutting member when the retaining arrangement is in the retaining condition.

61. A device according to claim 59 or claim 60, wherein the holding means comprises one or more arms.

62. A device according to claim 61 , wherein the or each arm includes a protuberance for engaging the or each resilient member.

63. A device according to claim 62, wherein the or each protruberance extends inwardly towards the bore of the housing.

64. A device according to any of claims 61 to 63, wherein the or each arm extends from the skin engaging portion.

65. A device according to any of claims 61 to 64, wherein the housing includes one or more channels for receiving the or each arm.

66. A device according to claim 65, wherein the or each channel extends from the second end of the housing longitudinally along its outer surface and slidably receives the or each arm.

67. A device according to claim 66, wherein the or each channel includes a slot extending from the outer surface of the housing into the bore for receiving a corresponding protuberance on the or each arm.

68. A device according to claim 67, wherein the or each protuberance is movable longitudinally within the or each corresponding slot.

69. A device according to any preceding claim, wherein the device includes a wiping arrangement for cleaning skin prior to collecting blood.

70. A device according to claim 69 when dependent on claim 55, wherein the wiping arrangement is provided on the trigger arrangement.

71. A device according to claim 70, wherein the wiping arrangement is provided on the skin engaging portion.

72. A device according to any of claims 69 to 71 , wherein the wiping arrangement is automatically actuable.

73. A device according to any of claims 70 to 72, wherein the trigger arrangement includes wiper actuating means to actuate the wiping arrangement.

74. A device according to claim 73, wherein the wiping arrangement is actuated by movement of the trigger arrangement from the first condition to the second condition.

75. A device according to any of claims 69 to 74, wherein the wiping arrangement provides a seal between the device and the skin to enable collection of uncontaminated blood by the blood collector when the cutting member is in the cutting condition.

76. A device according to any of claims 69 to 75, wherein the wiping arrangement comprises an annular wiping member.

77. A device according to claim 76, wherein the wiping member comprises a resilient material.

78. A device according to claim 77, wherein the resilient material comprises a region of weakness.

79. A device according to any of claims 76 to 78, wherein the wiping member includes wiping projections.

80. A device according to any of claims 76 to 79, wherein the wiping arrangement includes a mounting member for mounting the wiping member on the trigger arrangement.

81. A device according to claim 80, wherein retaining means are provided on the wiping member to retain the wiping member on the mounting member under tension.

82. A device according to claim 81 , wherein the retaining means comprises co-operating formations on the wiping member and the trigger arrangement, the formations co-operating to retain the wiping member on the trigger arrangement.

83. A device according to claim 82, wherein the co-operating formations comprise a projection formation and a recess formation on the wiping member and the trigger arrangement.

84. A device according to claim 83, wherein the projection formation is provided on the wiping member, and the recess formation is defined on the trigger arrangement.

85. A device according to claim 83 or claim 84, wherein where the wiping member is of an annular configuration, the projection formation comprises at least one annular bead, and the recess formation comprises at least one annular recess to receive the annular bead.

86. A device according to any of claims 76 to 85, wherein the wiping member comprises a plastics or rubber material.

87. A device according to any of claims 78 to 86, wherein the wiper actuating means co-operates with the region of weakness on the wiping member to actuate the wiping arrangement.

88. A device according to claim 87, wherein the wiper actuating means comprises a cutting projection on the trigger arrangement.

89. A device according to any preceding claim, wherein the device includes a handle.

90. A device according to claim 89, wherein the handle is removably mountable on the first end of the housing.

91. A device according to any preceding claim, wherein the device comprises plastics material, and is preferably formed by injection moulding.

92. A device according to any preceding claim, wherein the device is arranged to collect blood from a foetal scalp.

93. A device according to any preceding claim, wherein the device includes a blood detection system for detecting the presence of blood in the blood collector.

94. A device according to claim 93, wherein the detection system is operable to detect the presence of a predetermined amount of blood in the blood collector.

95. A device according to claim 94, wherein the device is operable to provide for the detection of the presence of blood at the first end of the blood collector.

96. A device according to any of claims 93 to 95, wherein the detection system includes an indicator for indicating the presence of blood in the blood collector.

97. A device according to claim 96, wherein the indicator comprises a light- emitting diode (LED).

98. A device according to any of claims 93 to 97, wherein the blood detection system comprises an electromagnetic radiation emission/detection arrangement.

99. A device according to claim 98, wherein the emission/detection arrangement comprises an emitter for emitting electromagnetic radiation on one side of the blood collector and a receiver for receiving emitted electromagnetic radiation on an opposite side of the blood collector.

100. A device according to claim 99, wherein the receiver is operable to detect a variation in the amount of emitted electromagnetic radiation transmitted through the blood collector due to presence of blood therein.

101. A device according to claim 100, wherein the emission/detection arrangement comprises a further receiver for receiving reflected electromagnetic radiation.

102. A device according to claim 101 , wherein the further receiver is operable to detect a variation in the amount of reflected electromagnetic radiation due to presence of blood in the blood collector.

103. A device according to claim 102, wherein the further receiver is operable to receive reflected electromagnetic radiation at substantially the same location as electromagnetic radiation is emitted by the emitter.

104. A device according to any of claims 101 to 103, wherein one or more of the emitter, receiver and further receiver are located adjacent the blood collector.

105. A device according to claim 104, wherein one or more of the emitter, receiver and further receiver are provided on the blood collector holding means.

106. A device according to claim 101 or claim 102, wherein one or more of the emitter, receiver and further receiver are located remote from the blood collector, transmission means being provided for transmitting electromagnetic radiation between the emitter, receiver, further receiver and the blood collector.

107. A device according to claim 106, wherein the transmission means comprises a light transmitting material.

108. A device according to claim 107, wherein the material comprises optical fibres.

109. A device according to any of claims 99 to 108, wherein the electromagnetic radiation emission/detection arrangement is arranged to emit and detect infrared electromagnetic radiation.

110. A device according to claim 109, wherein the emission/detection arrangement is arranged to emit infrared light.

111. A device according to any of claims 93 to 97, wherein the blood detection system comprises a detection arrangement for detecting a change of capacitance due to presence of blood in the blood collector.

112. A device according to claim 111 , wherein the detection arrangement comprises a coil positioned around the blood collector and having a self- capacitance, the self-capacitance increasing when blood is present in the blood collector.

113. A device according to claim 111 , wherein the detection system comprises two substantially annular metallic members spaced longitudinally along the blood collector and having therebetween a capacitance.

114. A device according to claim 113, wherein the capacitance increases due to presence of blood in the blood collector in the space defined between the metallic members.

115. A device according to any of. claims 93 to 97, wherein the blood detection system comprises a resistance wire extending into the bore of the blood collector, electrical resistance between the wire and the skin decreasing, in use, when blood is present in the blood collector between skin and the wire.

116. A device according to any of claims 93 to 97, wherein the blood detection system comprises a piezo-electric transducer for oscillating the blood collector and measuring a decrease in the resonant frequency of the blood collector due to the presence of blood therein.

117. A blood detection system for detecting the presence of blood in a blood collector of a blood collection device as defined in any preceding claim.

118. A method of operating a blood collection device including a blood collector and a cutting member movable between a primed condition and a cutting condition, the method comprising locating the blood collection device adjacent skin, moving, under spring bias, the cutting member from the primed condition to the cutting condition to incise the skin, and collecting blood from the incision in the blood collector.

119. A method of collecting blood comprising providing a blood collection device including a blood collector and a cutting member movable between a primed condition and a cutting condition, locating the cutting member adjacent skin, moving under spring bias, the cutting member from the primed condition to the cutting condition to incise the skin, and collecting blood from the incision in the blood collector.

120. A method according to claim 118 or claim 119, wherein the method comprises the step of moving the cutting member, under spring bias, from the cutting condition to a retracted condition.

121. A method according to any of claims 118 to 120, wherein the method includes the step of detecting the presence of blood in the blood collector.

122. A method according to any of claims 118 to 121 , wherein the method includes the step of locating the blood collection device adjacent a foetal scalp and collecting blood from the foetal scalp.

123. A method according to any of claims 118 to 122, wherein the blood collection device is as defined in any of claims 1 to 116.

124. A blood collection device comprising a housing, a cutting member movable between a retracted condition and a cutting condition, a blood collector for collecting blood when the cutting member is moved to the cutting condition, and a blood detection system for detecting the presence of blood in the blood collector.

125. A device according to claim 124, wherein the detection system is operable to detect the presence of a predetermined amount of blood in the blood collector.

126. A device according to claim 124 or claim 125, wherein the blood collector has first and second ends, the detection system providing for detection of the presence of blood at the first end thereof.

127. A device according to any of claims 124 to 126, wherein the detection system includes an indicator for indicating the presence of blood in the blood collector.

128. A device according to claim 127, wherein the indicator comprises a light- emitting diode (LED).

129. A device according to any of claims 124 to 128, wherein the blood detection system comprises an electromagnetic radiation emission/detection arrangement.

130. A device according to claim 129, wherein the arrangement comprises an emitter for emitting electromagnetic radiation on one side of the blood collector and a receiver for receiving emitted electromagnetic radiation on an opposite side of the blood collector.

131. A device according to claim 130, wherein the receiver is operable, to detect a variation in the amount of emitted electromagnetic radiation transmitted through the blood collector due to presence of blood therein.

132. A device according to claim 130 or claim 131 , wherein the electromagnetic radiation emission/detection arrangement comprises a further receiver for receiving reflected electromagnetic radiation.

133. A device according to claim 132, wherein the further receiver is operable to detect a variation in the amount of reflected electromagnetic radiation due to presence of blood in the blood collector.

134. A device according to claim 133, wherein the further receiver is operable to receive reflected electromagnetic radiation at substantially the same location as electromagnetic radiation is emitted by the emitter.

135. A device according to any of claims 132 to 134, wherein one or more of the emitter, receiver and further receiver is located adjacent the blood collector.

136. A device according to claim 135, wherein the blood collection device includes a blood collector holding means, one or more of the emitter, receiver and further receiver being provided on the holding means.

137. A device according to claim 132 or claim 133, wherein one or more of the emitter, receiver and further receiver is located remote from the blood collector, transmission means being provided for transmitting electromagnetic radiation between the emitter, receiver, further receiver and the blood collector.

138. A device according to claim 137, wherein the transmission means comprises a light transmitting material.

139. A device according to claim 138, wherein the material comprises optical fibres.

140. A device according to any of claims 129 to 139, wherein the electromagnetic radiation emission/detection arrangement is arranged to emit and detect infrared electromagnetic radiation.

141. A device according to claim 140, wherein the emission/detection arrangement is arranged to emit and detect infrared light.

142. A device according to any of claims 124 to 128, wherein the blood detection system comprises a detection arrangement for detecting a change of capacitance due to presence of blood in the blood collector.

143. A device according to claim 142, wherein the detection arrangement comprises a coil positioned around the blood collector and having a self capacitance, the self-capacitance increasing when blood is present in the blood collector.

144. A device according to claim 143, wherein the detection system comprises two substantially annular metallic members spaced longitudinally along the blood collector and having therebetween a capacitance.

145. A device according to claim 144, wherein the capacitance increases due to presence of blood in the blood collector in the space defined between the metallic members.

146. A device according to any of claims 124 to 128, wherein the blood detection system comprises a resistance wire extending into the bore of the blood collector, electrical resistance between the wire and the skin decreasing, in use, when blood is present in the blood collector between skin and the wire.

147. A device according to any of claims 124 to 128, wherein the blood detection system comprises a piezo-electric transducer for oscillating the blood collector and measuring a decrease in the resonant frequency of the blood collector due to presence of blood therein.

148. A blood collection device substantially as hereinbefore described and/or as shown in the accompany drawings.

149. A method of operating a blood collection device substantially as hereinbefore described and/or as shown in the accompanying drawings.

150. A method of collecting blood substantially as hereinbefore described and/or as shown in the accompanying drawings.

151. A blood detection system substantially as hereinbefore described and/or as shown in the accompanying drawings.

152. Any novel subject matter or combination including novel subject matter disclosed herein, whether or not within the scope of or relating to the same invention as any of the preceding claims.