GB2543652A - Improved tourniquet release device and tourniquet incorporating the same - Google Patents

Abstract

A tourniquet release device 3 comprises a body 5 having first 7 and second 15 parts for retaining first 11 and second 17 portions of a tourniquet strap 13. The body 5 or a leg 19 thereof - is further movable between two conditions; a first in which the strap 13 is prevented from disengaging from the body 5, and a second achieved after a period of time, in which the strap 13 is able to disengage from the body 5. A suction cup 25 provided with a means 33 for allowing the ingress of air into the cup 25 may act as the means for actuating the transition between the conditions. A time indicator in the form of a blister containing a coloured liquid, whereby upon rupture of the blister the liquid penetrates a porous portion of the device, is also taught. The extent of penetration by the coloured liquid provides an indication as to the time elapsed since the blister was ruptured. An indicator (280, Fig 9) which becomes visible to a user after a plug (209, Fig 9) of a tourniquet strap has been inserted into the body a predetermined number of times is also taught.

Description

Improved Tourniquet Release Device and Tourniquet Incorporating the Same

The present invention relates to an improved tourniquet release device and a tourniquet incorporating the same. A tourniquet is a constricting device which is used to control blood circulation to a limb of a patient for a period of lime. Pressure is applied circumferentially around llie limb, wliich pressure is transferred to the walls of blood vessels, causing them to become temporarily occluded. A tourniquet can be used generally as a tool for a clinician during cannulation for example, or during surgery.

Despite being widely used in this way, if a tourniquet is inadvertentiy left on the limb of the patient for too long, problems can ensue, such as pain, discomfort, bruising and in severe cases, embolism. Moreover, blood test results can be rendered inaccurate, often resulting in the need for repetition of the blood test, which is inconvenient and time consuming.

Several different products are currendy available, which aim to alleviate this problem; however, these products can be complicated to use and expensive to manufacture. There exists a need for a convenient and reliable tourniquet release mechanism that is inexpensive to manufacture and easy to use by the clinician, which prevents the tourniquet from inadvertendy being left on the limb of the patient for too long.

The aim of the present invention is to overcome, or at least alleviate, at least the above mentioned disadvantages of the prior art.

In accordance with a first aspect of the present invention there is provided a tourniquet release device for releasing a tourniquet strap from a limb of a patient after a period of time, said device comprising: - a body comprising a first part for selectively retaining a first portion of a tourniquet strap and a second part for retaining a second portion of said tourniquet strap, said second portion of said tourniquet strap being distant from said first portion of said tourniquet strap, wherein said body is movable between a first condition in which said first portion of said tourniquet strap is prevented from disengaging from said body, and a second condition achieved after said period of time, in which said first portion of said tourniquet strap is able to disengage from said body.

This provides the advantage that the tourniquet strap is automatically released from the limb of the patient after the period of time, which prevents the patient from suffering any adverse effects caused by the tourniquet being inadvertently left on their limb for too long a time.

Said tourniquet release device may further comprise a suction cup and means for allowing the ingress of air into said suction cup, wherein said means for allowing the ingress of air into said suction cup actuates die transition between said first and second conditions.

When in said first condition, said suction cup may be temporarily fixed to a substantially flat portion of said body such that a first engaging portion prevents the first portion of said tourniquet strap from disengaging from said first rebate, and when said body is in said second condition, said suction cup is not in suction contact with said substantially flat portion of said body such that the first engaging portion does not prevent the first portion of said tourniquet strap from disengaging from said first rebate.

In a first preferred embodiment, said first part of said body is a first rebate and said first portion of said tourniquet strap comprises a plug portion adapted for selective retention inside said first rebate, wherein when in said first condition, said plug portion is prevented from disengaging from said first rebate, and when in said second condition, said plug portion is able to disengage from said first rebate, wherein said second part of said body comprises a retention slot for retaining said second portion of said tourniquet strap.

This provides the advantage that the tourniquet can be quickly and easily applied to the limb of the patient by wrapping the tourniquet strap around the limb and inserting the plug portion into the first rebate, and pulling the second portion of the tourniquet strap through the retention slot until the tourniquet strap is at the correct size for the limb of the patient, whereby the plug portion is retained in position for the period of time, which is a period of time which would not be sufficient to cause any adverse effects to the patient.

Said body may comprise a movable leg portion such that, when said body is in said first condition, said leg portion is engaged with said plug portion for said period of time, and when said body is in said second condition, said leg portion is not engaged with said plug portion.

This provides the advantage that the leg portion can be quickly and easily moved into engagement with the plug portion in order to retain the plug portion inside the first rebate for the predetermined period of time.

Said leg portion may comprise a first end pivotally connected to said body, and a second end comprising said suction cup, wherein when in said first condition, said suction cup is temporarily fixed to a substantially flat portion of said body such that said first engaging portion, which is disposed on saidleg portion, engages with a corresponding portion on said plug portion in order to prevent the plug portion from disengaging from said first rebate, and when said body is in said second condition, said suction cup is not in suction contact with said substantially flat portion of said body such that the first engaging portion of said leg portion does not engage with said plug portion.

This provides the advantage that the suction cup can provide a simple and convenient solution for retaining the leg portion in a position such that it engages with the plug portion to maintain the body in the first condition, for the period of time.

Said substantially flat portion of said body may comprise said means for allowing for the ingress of air into the interior of said suction cup.

Said means for allowing for the ingress of air into the interior of said suction cup may comprise an aperture through said substantially flat portion of said body, said aperture defining a channel connecting the interior of the suction cup with the ambient.

This provides the advantage that the suction cup is only in engagement with the substantially flat portion of the body for a period of time, since the aperture facilitates the slow ingress of air into the interior of the suction cup, which gradually results in the suction fit releasing itself, to allow for the leg portion to move out of engagement with the plug portion.

It is to be appreciated that the duration of the period of time can be defined by the diameter of the aperture, such that the larger the diameter of the aperture, the quicker the ingress of air into the interior of the suction cup, and therefore the shorter the duration of the period of time.

Alternatively, said means for allowing for the ingress of air into the interior of said suction cup may comprise a groove on the surface of said substantially flat portion of said body, said groove defining a channel connecting the interior of the suction cup with the ambient.

This provides an alternative to the aperture, providing a solution which is quick and easy to etch onto the substantially flat portion of the body, for example.

Alternatively, said means for allowing for the ingress of air into the interior of said suction cup may comprise an aperture in said suction cup.

Said first engaging portion of the leg portion may be a raised portion and said corresponding portion on said plug portion may be a recess shaped to receive said raised portion.

Said tourniquet release device may further comprise a visual indicator which becomes visible to a user after said plug portion has been inserted into said first rebate a predetermined number of times.

This provides the advantage that the user is provided with a warning after the tourniquet release device has been used a predetermined number of times, so that they can then discard the device and begin using a new one when required.

Said visual indicator may comprise a visual indicator element moveable in a longitudinal direction towards an indicator window, and a rotatable tubular control element, wherein said visual indicator element is moved in a direction towards said indicator window by means of rotation of said tubular control element.

This provides the advantage that the user is clearly alerted to the need to discard the tourniquet release device after the predetermined number of uses, by seeing the visual indicator element, which may be coloured red for example, exposed through the indicator window.

One of said plug portion and said first part of said body may comprise a recess inside of which is disposed said tubular control element, said tubular control element being rotatable within said recess in a first sense about a first axis, said tubular control element comprising a first threaded end and a second end comprising a plurality of elongate formations disposed around the periphery of said second end and extending in a direction substantially parallel to said first axis, said tubular control element being substantially prevented from moving in a direction parallel to said first axis, and wherein the other of said plug portion and said first part of said body comprises an elongate engaging member such that when said plug portion is inserted into said first part of said body, a free end of said elongate engaging member engages with at least one said elongate formation to cause said tubular control element to rotate about said first axis in said first sense, wherein said one of said plug portion and said first part of said body further comprises an elongate track extending substantially parallel to said first axis, whereby as said tubular control element rotates, said visual indicator element moves along said track in a direction towards said indicator window, said indicator window being disposed in said one of said plug portion and said first part of said body.

This provides the advantage that the tourniquet release device is inexpensive to manufacture and provides a convenient solution which involves using rotational movement to effect translational movement of the visual indicator element.

At least one said elongate formation may be an elongate tooth.

Said visual indicator element may comprise a substantially planar member having at least one protrusion, said protrusion engaging with said first threaded end of said tubular control element, such that as said tubular control element rotates, said visual indicator element moves along said track in a direction towards said indicator window.

Said tubular control element may be substantially prevented from rotating in a second sense opposite to said first sense by means of a pawl disposed in said recess and engageable with at least one said elongate tooth, whereby said pawl extends in a direction substantially perpendicular to said first axis.

This provides the advantage that the visual indicator element only moves when the plug portion is inserted into the first rebate, and not when the plug portion is removed from the first rebate.

Said free end of said elongate engaging member may comprise a rebate at said free end, and said tubular control element is additionally moveable in said recess in a direction substantially perpendicular to said first axis, such that when said plug portion is pulled in a direction such as to remove said plug portion from said first part of said body, said free end of said elongate engaging member engages with at least one said elongate tooth of said tubular control element to cause said tubular control element to move in said direction substantially perpendicular to said first axis so that said tubular control element does not prevent said plug portion from being removed from said first part of said body.

This provides the advantage that the feature of the tubular control element only being able to rotate in a first sense does not prevent the plug portion from being removed from the first rebate, when required. That is, the tubular control element is moved out of the way of the plug portion as the plug portion is removed from the first part of the body.

Said recess may further comprise a biasing member for biasing said tubular control element towards a position whereby said tubular control element prevents said plug portion from being removed from said first part of said body.

Said biasing member may comprise a spring.

Said tourniquet release device may further comprise a time indicator which, after actuation by a user, provides a visual indication to a user after a second period of time has elapsed.

This provides the advantage that the user is provided with a warning when the tourniquet release device has been in operation (whereby operation consists of a number of uses involving the movement between the first condition and the second condition, that is, a number of applications to the limbs of patients) for a period of time which warrants the discarding of the tourniquet release device. It is to be appreciated that the afore mentioned second period of time involving the time indicator is intended for a completely different purpose than the period of time after which the tourniquet release device moves from the first condition to the second condition when it is in situ on the limb of a patient.

Said time indicator may comprise a blister containing a coloured liquid, whereby upon rupture of said blister, said coloured liquid penetrates a porous portion of said tourniquet release device, whereby the extent of penetration of the porous portion by the coloured liquid provides an indication to a user of the time elapsed since the blister was raptured.

It is to be appreciated that the insertion of the plug portion into the first rebate by a user could effect the rapture of the blister by the plug portion In this case, the blister could be disposed inside the body, for example,

Said body may further comprise a suction cup release means, said suction cup release means comprising a lever having a free end comprising a lip, wherein depression of said free end of said lever by a user causes the lip to engage with said suction cup and lift it from said substantially flat portion.

This provides the advantage that the suction cup can be released by a user, before the natural release of the suction cup after the period of time, if required.

Alternatively, said suction cup release means may comprise may comprise a button, wherein depression of said button by a user causes a portion of the button to engage with said suction cup and lift it from said substantially flat portion.

In a further embodiment, said first part of said body may be a first rebate, wherein when in said first condition, said first portion of said tourniquet strap is prevented from disengaging from said first rebate, and when in said second condition, said first portion of said tourniquet strap is able to disengage from said first rebate, wherein said second portion of said tourniquet strap comprises a plug portion adapted for retention inside said second part, wherein said second part of said body comprises a retention slot for retaining said plug portion of said second portion of said tourniquet strap.

This provides the advantage that the tourniquet can be quickly and easily applied to the limb of the patient by wrapping the tourniquet strap around the limb, inserting the plug portion inside the retention slot, and pulling the first portion of the tourniquet strap through the first rebate until the tourniquet strap is at the correct size for the limb of the patient, whereby the first portion of the tourniquet strap can be retained in position for the period of time which is a period of time which would not be sufficient to cause any adverse effects.

Said retention slot may be adapted so that once said plug portion is inside said retention slot, it cannot be removed.

This provides the advantage that the tourniquet can be utilised as a single use item.

Said body may comprise a movable leg portion such that, when said body is in said first condition, said leg portion is engaged with said first portion of said tourniquet strap for said period of time to substantially grip said first portion of said tourniquet strap and substantially prevent it from disengaging from said first rebate, and when said body is in said second condition, said leg portion does not substantially grip said first portion of said tourniquet strap and does not substantially prevent it from disengaging from said first rebate.

This provides the advantage that the leg portion can be quickly and easily moved into engagement with the first portion of the tourniquet strap in order to retain the first portion of the tourniquet strap in position inside the first rebate.

Said leg portion may comprise a first end pivotally connected to said body, and a second end comprising said suction cup, such that when said body is in said first condition, said suction cup is temporarily fixed to said substantially flat portion of said body such that said first engaging portion, which is disposed on said leg portion, engages with said first portion of said tourniquet strap to substantially grip said first portion of said tourniquet strap and substantially prevent it from disengaging from said first rebate, and when said body is in said second condition, said suction cup is not in suction contact with said substantially flat portion of said body such that the first engaging portion of the leg portion does not substantially grip said first portion of said tourniquet strap and substantially prevent it from disengaging from said first rebate..

This provides the advantage that the suction cup can provide a simple and convenient solution for retaining the leg portion in a position such dial it engages with the first portion of the tourniquet strap to maintain the body in the first condition, for the period of time.

Said substantially flat portion of said body may comprise said means for allowing for the ingress of air into the interior of said suction cup.

Said means for allowing for the ingress of air into the interior of said suction cup may comprise an aperture through said substantially flat portion of said body, said aperture defining a channel connecting the interior of the suction cup with the ambient.

This provides the advantage that the suction cup is only in engagement with the substantially flat portion of the body for said period of time, since the aperture facilitates the slow ingress of air into the interior of the suction cup, which gradually results in the suction fit releasing itself, to allow for the leg portion to move out of engagement with the first portion of the tourniquet strap.

It is to be appreciated that the duration of the period of time can be defined by the diameter of the aperture, such that the larger the diameter of the aperture, the quicker the ingress of air into the interior of the suction cup, and therefore the shorter the duration of the period of time.

Alternatively, said means for allowing for the ingress of air into the interior of said suction cup comprises a groove on the surface of said substantially flat portion of said body, said groove defining a channel connecting the interior of the suction cup with the ambient.

This provides an alternative to the aperture, providing a solution which is quick and easy to etch onto the substantially flat portion of the body, for example.

Alternatively, said means for allowing for the ingress of air into the interior of said suction cup may comprise an aperture in said suction cup.

Said first engaging portion of the leg portion may be a raised portion and said body may comprise a corresponding portion in the form of a recess shaped to receive said raised portion, such that when said body is in said first condition, said first portion of said tourniquet strap is gripped between said raised portion and said corresponding portion.

It is however to be appreciated that said raised portion of said leg portion could also provide a gripping action on said first portion of said tourniquet strap without the requirement for said corresponding portion in the form of said recess.

Said body may comprise a biasing means, for biasing said body towards the second condition. Said biasing means may comprise a spring member.

In accordance with a second aspect of the present invention there is provided a tourniquet comprising a tourniquet release device for releasing a tourniquet strap from a limb of a patient after a period of time, as described above.

Preferred embodiments of the present invention will now be described, by way of example only and not in any limitative sense, with reference to the accompanying drawings in which: -

Figure 1 shows a side view showing hidden detail of a tourniquet comprising a tourniquet release device in a second condition, in accordance with a first embodiment of the present invention;

Figure 2 shows a side view showing hidden detail of a tourniquet comprising a tourniquet release device in a first condition, in accordance with a first embodiment of the present invention;

Figure 3 shows a side view showing hidden detail of a tourniquet comprising a tourniquet release device in a second condition, in accordance with a second embodiment of the present invention;

Figure 4 shows a side view showing hidden detail of a tourniquet comprising a tourniquet release device in a first condition, in accordance with a second embodiment of the present invention;

Figure 5 shows a perspective view of the tourniquet of Figures 1 and 2;

Figure 6 shows a perspective view of the tourniquet of Figures 3 and 4;

Figure 7 shows a side view showing hidden detail of a tourniquet comprising a tourniquet release device in a first condition, in accordance with a third embodiment of the present invention;

Figure 8 shows a side view showing hidden detail of a tourniquet comprising a tourniquet release device in a second condition, in accordance with a third embodiment of the present invention;

Figure 9 shows a top plan view showing hidden detail of a portion of the tourniquet release device of Figures 7 and 8;

Figure 9a shows a side view of a portion of the tourniquet release device of Figures 7, 8 and 9;

Figure 10 shows a side view showing hidden detail of a tourniquet comprising a tourniquet release device in a second condition, in accordance with a fourth embodiment of the present invention; and

Figure 11 shows a perspective view of a tourniquet comprising a tourniquet release device in accordance with a fourth embodiment of the present invention.

Referring first to Figures 1, 2 and 5, a first embodiment of a tourniquet is represented generally by reference numeral 1. The tourniquet 1 comprises a tourniquet retention and release device 3 comprising a body 5. The body 5 comprises a first part in the form of a first rebate 7 for selectively retaining a plug portion 9 which is attached to a first portion 11 of a tourniquet strap 13. The body 5 further comprises a second part in the form of a retention slot 15 for selectively retaining a second portion 17 of the tourniquet strap 13.

As can be clearly seen from Figures 1, 2 and 5, the body 5 is movable between a first condition (shown in Figure 2), in which the plug portion 9 is prevented from disengaging from the first rebate 7 of the body 5 (in other words it is retained by the body) and a second condition (shown in Figure 1), achieved after a period of time, in which the plug portion 9 is able to disengage from the first rebate 7 of the body 5 (in other words it is released by the body).

As can also be clearly seen from Figures 1, 2 and 5, the body 5 comprises a movable leg portion 19 such that, when the body 5 is in the first condition as shown in Figure 2, the leg portion 19 is engaged with the plug portion 9 for the period of time before being released from engagement with the plug portion 9. Moreover, when the body 5 is in the second condition as shown in Figure 1, the leg portion 19 is not engaged with the plug portion 9.

The leg portion 19 comprises a first end 21 pivotally comiecled to the body 5, and a second end 23 comprising a suction cup 25. It is to be appreciated that, when in the first condition as shown in Figure 2, the suction cup 25 is fixed via suction to a substantially flat portion 27 of the main body 5 such that a first engaging portion of the leg portion 19 in the form of a raised portion 29 engages with a corresponding portion on the plug portion 9 in the form of a recess 31, to prevent the plug portion 9 from disengaging from the first rebate 7.

The substantially flat portion 27 of the body 5 comprises a means for allowing for the ingress of air into the interior of the suction cup 25, in the form of an aperture 33 through the substantially flat portion 27, which defines a channel connecting the interior of the suction cup 25 with the exterior of the body 5. The aperture 33 could have a diameter of any suitable size but could for example have a diameter in the range five micrometres to twenty micrometres, such as five micrometres.

It is however to be appreciated that as an alternative to said aperture through said substantially flat portion 27, said substantially flat portion 27 could be provided with a groove (not shown). As a further alternative, said substantially flat portion 27 could comprise a porous material.

The body 5 further comprises a tab 37 on said suction cup 25, for allowing a user to manually release the suction cup 25 from the suction fit with the substantially flat portion 27, if required.

As an alternative, the body 5 could further comprise a needle valve (not shown) for facilitating manual release of the suction cup 25 from the suction fit with the substantially flat portion 27, if required.

Method of Use of the Tourniquet 1

In order to use the tourniquet 1, the user first of all wraps the tourniquet strap 13 around the limb of the patient, and then inserts the plug portion 9 into the first rebate 7. They then push down on the second end 23 of the leg portion 19 until the suction cup 25 is fixed via suction to the substantially flat portion 27, which prevents the plug portion 9 from being released from the first rebate 7 for the period of time.

As an alternative to first inserting the plug portion 9 into the first rebate 7 and then pushing down on the second end 23 of the leg portion 19 to fix said suction cup 25 to the substantially flat portion 27, the user could instead first push down on the second end 23 of the leg portion 19 to fix said suction cup 25 to the substantially flat portion 27, and then insert the plug portion 9 into the first rebate 7 by way of forcing the plug portion 9 into the first rebate 7 past the raised portion 29. This is facilitated by the chamfered comer 9a of the plug portion 9.

The user then pulls the second portion 17 of the tourniquet strap 13 until the tourniquet strap 13 is sufficiently tight that it applies the required compression to the limb of the patient. The presence of the aperture 33 and the resulting slow ingress of air into the interior of the suction cup 25 ensures that the suction cup 25 will eventually be released from the substantially flat portion 27, with the length of time elapsing before this occurs (i.e. the period of time) being defined by the diameter of the aperture 33. Once the suction cup 25 is released from the substantially flat portion 27 then the plug portion 9 is able to be released from the first rebate 7, to remove the compression from the limb of the patient. The tension in the tourniquet strap 13 causes the plug portion 9 to pop out from the first rebate 7 once the suction cup 25 is released.

Turning now to Figures 3, 4 and 6, a second embodiment of a tourniquet is represented generally by reference numeral 101. The tourniquet 101 comprises a tourniquet release device 103 comprising a body 105. The body 105 comprises a first part in the form of a first rebate 107 for selectively retaining a first portion 111 of a tourniquet strap 113. The body 105 further comprises a second part in the form of a retention slot 115 for selectively retaining a plug portion 109 attached to a second portion 118 of the tourniquet strap 113.

As can be clearly seen from Figures 3, 4 and 6, the body 105 is movable between a first condition (shown in Figure 4), in which the first portion 111 of the tourniquet strap 113 is prevented from disengaging from the first rebate 107 of the body 105 (in other words it is retained by the body), and a second condition (shown in Figure 3), achieved after a period of time, in which the first portion 111 of the tourniquet strap 113 is able to disengage from the first rebate 107 of the body 105 (in other words it is released by the body).

As can also be clearly seen from Figures 3, 4 and 6, the body 105 comprises a movable leg portion 119 such that, when the body 105 is in the first condition as shown in Figure 4, the leg portion 119 is engaged with the first portion 111 of the tourniquet strap 113 for the period of time before being released from engagement with the first portion 111 of the tourniquet strap 113. Moreover, when the body 105 is in the second condition as shown in Figure 3, the leg portion 119 is not engaged with the first portion 111 of the tourniquet strap 113 to an extent that it does not retain the first portion 111 of the tourniquet strap 113 in position. It is to be appreciated that the leg portion 119 could be resting on or touching the first portion 111 of the tourniquet strap 113 without actually gripping it, and in this way, would not be truly engaged.

The leg portion 119 comprises a first end 121 pivotally connected to the body 105, and a second end 123 comprising a suction cup 125 It is to be appreciated that, when in the first condition as shown in Figure 4, the suction cup 125 is fixed via suction to a substantially flat portion 127 of the main body 105 such that a first engaging portion of the leg portion 119 in the form of a raised portion 129 engages with a corresponding portion on the main body 105 in the form of a recess 131, to effectively grip the tourniquet strap 113 and prevent the tourniquet strap 113 from disengaging from the first rebate 107.

The substantially flat portion 127 of the body 105 comprises a means for allowing for the ingress of air into the interior of the suction cup 125 in the form of an aperture 133 through the substantially flat portion 127, which defines a channel connecting the interior of the suction cup 125 with the exterior of the body 105. The aperture 133 could have a diameter of any suitable size but could for example have a diameter in the range five micrometres to twenty micrometres, such as five micrometres.

It is however to be appreciated that as an alternative to said aperture 133 through said substantially flat portion 127, said substantially flat portion 127 could be provided with a groove (not shown). As a further alternative, said substantially flat portion 127 could comprise a porous material.

The body 105 further comprises a tab 137 on said suction cup 125, for allowing a user to manually release the suction cup 125 from the suction fit with the substantially flat portion 127, if required.

Method of Use of the Tourniquet 101

In order to use the tourniquet 101, the user first of all wraps the tourniquet strap 113 around the limb of the patient, and then inserts the plug portion 109 into the retention slot 115. It is to be appreciated that in this embodiment, once the plug portion 109 is inserted into the retention slot 115, it cannot be subsequently removed, and in this way, the tourniquet 101 is intended to be a single use item. The user then pulls the first portion 111 of the tourniquet strap 113 until the tourniquet strap 113 is sufficiently tight that is applies the required compression to the limb of the patient. The user then pushes down on the second end 123 of the leg portion 119 until the suction cup 125 is fixed via suction to the substantially flat portion 127, which clamps the first portion 111 of the tourniquet strap 113 between the raised portion 129 of the leg portion 119 and the recess 131 of the body 105 for the period of time. The presence of the aperture 133 and the resulting slow ingress of air into the interior of the suction cup 125 ensures that the suction cup 125 will eventually be released from the substantially flat portion 127, with the length of time elapsing before this occurs (i.e. the period of time) being defined by the diameter of the aperture 133. Once the suction cup 125 is released from the substantially flat portion 127 then the first portion 111 of the tourniquet strap 113 is no longer clamped in position and is instead able to be released from the first rebate 107, to remove the compression from the limb of the patient. The tension in the tourniquet strap 113 causes the first portion 111 to slide out from the first rebate 107 once the suction cup 125 is released.

Turning now to Figures 7, 8, 9 and 9a, a third embodiment of a tourniquet is represented generally by reference numeral 201. The tourniquet 201 is very similar to the tourniquet 1 of Figures 1, 2 and 5, and is used in the same way as the tourniquet 1 of Figures 1, 2 and 5 by a user. The tourniquet 201 comprises a tourniquet release device 203 comprising a body 205. The body 205 comprises a first part in the form of a first rebate 207 for selectively retaining a plug portion 209 which is attached to a first portion 211 of a tourniquet strap 213. The body 205 further comprises a second part in the form of a retention slot 215 for selectively retaining a second portion 217 of the tourniquet strap 213.

As can be clearly seen from Figures 7 and 8, the body 205 is movable between a first condition (shown in Figure 7), in which the plug portion 209 is prevented from disengaging from the first rebate 207 of the body 205 (in other words it is retained by the body) and a second condition (shown in Figure 8), achieved after a period of time, in which the plug portion 209 is able to disengage from the first rebate 207 of the body 205 (in other words it is released by the body).

As can also be clearly seen from Figures 7 and 8, the body 205 comprises a movable leg portion 219 such that, when the body 205 is in the first condition as shown in Figure 7, the leg portion 219 is engaged with the plug portion 209 for the period of time before being released from engagement with the plug portion 209. Moreover, when the body 205 is in the second condition as shown in Figure 8, the leg portion 219 is not engaged with the plug portion 209.

The leg portion 219 comprises a first end 221 pivotally connected to the body 205, and a second end 223 comprising a suction cup 225. It is to be appreciated that, when in the first condition as shown in Figure 7, the suction cup 225 is fixed via suction to a substantially flat portion 227 of die main body 205 such that a first engaging portion of the leg portion 219 in the form of a raised portion 229 engages with a corresponding portion on the plug portion 209 in the form of a recess 231, to prevent the plug portion 209 from disengaging from the first rebate 207.

The substantially flat portion 227 of the body 205 comprises a means for allowing for the ingress of air into the interior of the suction cup 225, in the form of an aperture 233 through the substantially flat portion 227, which defines a channel connecting the interior of the suction cup 225 with the exterior of the body 205. The aperture 233 could have a diameter of any suitable size but could for example have a diameter in the range five micrometres to twenty micrometres, such as five micrometres. As can be clearly seen from Figures 7 and 8, the aperture is arranged so that the opening 233a of the aperture 233 is disposed to the side; that is, the opening 233a of the aperture 233 is not on the underside of the tourniquet 201, which would otherwise present a risk that the opening 233a of the aperture 233 could become blocked when the tourniquet 201 is in situ on the limb of the patient.

The body 205 further comprises a tab 237 on the suction cup 225, for allowing a user to manually release the suction cup 225 from the suction fit with the substantially flat portion 227, if required.

The tourniquet 201 and in particular the tourniquet release device 203 differs from the tourniquet 1 of Figures 1, 2 and 5 in that it additionally incorporates a visual indicator which provides a visual indication to a user after the plug portion 209 has been inserted into the first rebate 207 a predetermined number of times. That is, a visual indication is provided to a user after the tourniquet release device 203 has been used a predetermined number of times, to ensure that the user is provided with a warning when the tourniquet 201 has been used to an extent that it should be discarded. This is to support the intention that the tourniquet 201 is not a single use item, but should nevertheless be discarded after a number of uses to alleviate potential infection control issues and other potential issues such as the build up of dirt on the suction cup 225, which would otherwise prevent an adequate seal from being formed between the suction cup 225 and the substantially flat portion 227.

The visual indicator, which is shown in particular detail in Figure 9, comprises a visual indicator element in the form of a red coloured tab 280, which is shown in detail in Figure 9a. The red coloured tab 280 appears in an indicator window (not shown) of the plug portion 209 after the plug portion 209 has been inserted into the first rebate 207 a predetermined number of times. The predetermined number of times could be any suitable number of times, for example twenty or one hundred.

The plug portion 209 comprises a recess 284 inside of which is disposed a tubular control element 286. The tubular control element 286 is rotatable within the recess 284 in a first sense about the first axis A and it comprises two distinct ends - a first threaded end 286a and a second end 286b comprising a plurality of elongate formations in the form of elongate teeth 288 disposed around the periphery of the second end 286b. ft can be clearly seen from Figure 9 in particular that the elongate teeth 288 extend in a direction parallel to the first axis A.

In view of its disposition inside the recess 284, and in particular the arrangement of the walls of the recess 284, the tubular control element 286 is prevented from moving in a direction parallel to the first axis A. However, it is able to rotate about first axis A, as discussed previously.

Turning now to the body 205, the first rebate 207 comprises an elongate engaging member 290 which is arranged so that when the plug portion 209 is inserted into the first rebate 207, a free end 290a of the elongate engaging member 290 engages with an elongate tooth 288 on the underside of the tubular control element 286 in order to rotate the tubular control element 286 about the first axis A in the first sense (clockwise as shown in relation to Figures 7 and 8), by an increment. A free end 290a of the elongate engaging member 290 comprises a rebate 296 which facilitates the rotation of the tubular control element 286 about the first axis A in the first sense. To elaborate, when the plug portion 209 is inserted into the body 205 and the elongate engaging member 290 engages with an elongate tooth 288 to cause the tubular control element 286 to rotate, the rebate 296 provides clearance for the other elongate teeth behind the elongate tooth 288 with which the free end 290a of the elongate engaging member 290 is engaging, as the tubular control element 286 rotates. This rotation by an increment of the tubular control element 286 causes the red tab 280 to move in a direction towards the window (not shown), and this will be explained in further detail below.

The plug portion 209 further comprises an elongate track 281 which extends parallel to the first axis A on the topside of the tubular control element 286. Within the track 281 is disposed the red tab 280, which incorporates a protrusion 280a on one of its surfaces. The protrusion 280a is engaged with the first threaded end 286a of the tubular control element 286 and in view of the fact that the tubular control element 286 is unable to move in a direction parallel to the first axis A, then as the tubular control element 286 rotates, the red tab 280 is moved along the track 281 in a direction shown by the arrow in Figure 9 towards the indicator window (not shown) in the plug portion 209.

In tliis way, each time the plug portion 209 is inserted into die first rebate 207 of the body 205, the elongate engaging member 290 engages with an elongate tooth 288 and causes the tubular control element 286 to rotate by an increment, which in turn causes the red tab 280 to move towards the indicator window 282 by a distance defined by the pitch of the first threaded end 286a. To elaborate, the higher the pitch of the thread on the first threaded end 286a, that is, the more threads per unit length, the smaller the increment travelled by the red tab 280 each time the plug portion 209 is inserted into the first rebate 207. In this way, the more times the tourniquet 201 is used, that is, the more times the plug portion 209 is inserted into the first rebate 207, the closer the red tab 280 gets to the indicator window (not shown), until eventually, after the tourniquet release device 203 has been used the predetermined number of times, the red tab 280 becomes visible to a user in the indicator window, warning them that it is time to discard the tourniquet 201.

The tubular control element 286 is prevented from rotating in a second sense opposite to the first sense by means of a pawl 294 which is disposed in the recess 284 of the plug portion 209. The pawl 294 extends in an upwardly direction as shown in Figures 7 and 8 from the base of the recess 284 in a direction perpendicular to the first axis A, and it engages with at least one elongate tooth 288 on the tubular control element 286. In this way, once the tubular control element 286 has rotated in the first sense by an increment as a result of insertion of the plug portion 209 into the first rebate 207, it cannot rotate in the opposite sense as a result of engagement of the pawl 294 with the elongate tooth 288.

In order however to facilitate the removal of the plug portion 209 from the first rebate 207 when the tourniquet release device 203 is in its second condition whereby the leg portion 219 is not engaged with the plug portion 209, the tubular control element 286 is able to move by a small amount in a direction indicted by the arrow in Figures 7 and 8, to allow the elongate engaging member 290 to clear the tubular control element 286, to facilitate the removal of the plug portion 209 from the first rebate 207. This is further facilitated by the chamfered shape of a rebate 296 at the free end 290a of the elongate engaging member 290, such that as the plug portion 209 is released, a chamfered edge 296a of the rebate 296 urges the tubular control element 286 in the direction indicated by the arrow in Figures 7 and 8 to allow the elongate engaging member 290 to move past the tubular control element 286.

The tourniquet release device 203 further comprises a biasing member in the form of a spring (not shown) which biases the tubular control element 286 towards the position whereby the elongate engaging member 290 cannot move past the tubular control element 286.

Turning now to Figures 10 and 11, a fourth embodiment of a tourniquet is represented generally by reference numeral 301. The tourniquet 301 is very similar to the tourniquet 1 of Figures 1, 2 and 5, and is used in the same way by a user. It is to be appreciated that this embodiment of the tourniquet 301 could alternatively also include the visual indicator disclosed above with reference to Figures 7, 8, 9 and 9a.

The tourniquet 301 comprises a tourniquet release device 303 which differs from the tourniquet release device 3 of Figures 1, 2 and 5 in that it additionally includes a suction cup release means 306. The suction cup release means 306 comprises a lever 308 which is incorporated with the body 305. The lever 308 comprises a first end which incorporates a living hinge 312 to the upper portion of the main body 305, and a free end 310 comprising a lip 314. The purpose of the suction cup release means 306 is to allow a user to override the attachment of the suction cup 325 to the substantially flat portion 327 of the body 305 by pressing on the free end 310. The depression of the free end 310 of the lever 308 by a user causes the lip 314 on the free end 310 to engage with the suction cup 325 and lift it from the substantially flat portion 327 to release it from attachment thereto. The feature of the suction cup release means 306 is particularly useful in the case where a user is required to quickly remove the tourniquet 301 from the limb of a patient without having to wait for the suction cup 325 to naturally disengage from the substantially flat surface 327 after the period of time. However, the presence of the lever 308 as opposed to the presence of an exposed tab such as the tab 37 of Figures 1, 2 and 5, reduces the likelihood of a user accidentally releasing the suction cup 325 from engagement with the substantially flat surface 327.

Although in this embodiment the lip 314 engages directly with the suction cup 325 to lever the suction cup from engagement with the substantially flat portion 327 when required, it is however to be appreciated that the suction cup 325 could additionally include a tab (not shown), which may be smaller than the tab 37 of Figures 1, 2 and 5, to facilitate the release of the suction cup 325 by means of the lever 308.

The tourniquet release device 303 further differs from the tourniquet release device 3 of Figures 1, 2 and 5 in that the body 305 further includes a lid 320 over the leg portion 319 to provide a degree of protection to the tourniquet release device 303. The lid 320 of the body comprises a button aperture 340 through which a button 344 disposed on the leg portion 319 can protrude, to allow a user to conveniently move the body 305 from its second condition to its first condition as required.

It will be appreciated by persons skilled in the art that the above embodiments have been described by way of example only, and not in any limitative sense, and that various alterations and modifications are possible without departing from the scope of the invention as defined by the appended claims.

By means of example, it is to be appreciated that in respect of the embodiment of Figures 7, 8 and 9, the elements of the visual indicator that are disposed on the plug portion 209 could alternatively be disposed on the body 205, and the elements of the visual indicator that are disposed on the body 205 could alternatively be disposed on the plug portion 209.

Claims (37)

1. A tourniquet release device for releasing a tourniquet strap from a limb of a patient after a period of time, said device comprising: - a body comprising a first part for selectively retaining a first portion of a tourniquet strap and a second part for retaining a second portion of said tourniquet strap, said second portion of said tourniquet strap being distant from said first portion of said tourniquet strap, wherein said body is movable between a first condition in which said first portion of said tourniquet strap is prevented from disengaging from said body, and a second condition achieved after said period of time, in which said first portion of said tourniquet strap is able to disengage from said body.

2. A tourniquet release device as claimed in claim 1, wherein said tourniquet release device further comprises a suction cup and means for allowing the ingress of air into said suction cup, wherein said means for allowing the ingress of air into said suction cup actuates the transition between said first and second conditions.

3. A tourniquet release device as claimed in claim 2, wherein when in said first condition, said suction cup is temporarily fixed to a substantially flat portion of said body such that a first engaging portion prevents the first portion of said tourniquet strap from disengaging from said first rebate, and when said body is in said second condition, said suction cup is not in suction contact with said substantially flat portion of said body such that the first engaging portion does not prevent the first portion of said tourniquet strap from disengaging from said first rebate.

4. A tourniquet release device as claimed in any one of the previous claims, wherein said first part of said body is a first rebate and said first portion of said tourniquet strap comprises a plug portion adapted for selective retention inside said first rebate, wherein when in said first condition, said plug portion is prevented from disengaging from said first rebate, and when in said second condition, said plug portion is able to disengage from said first rebate, wherein said second part of said body comprises a retention slot for retaining said second portion of said tourniquet strap.

5. A tourniquet release device as claimed in claim 4, wherein said body comprises a movable leg portion such that, when said body is in said first condition, said leg portion is engaged with said plug portion for said period of time, and when said body is in said second condition, said leg portion is not engaged with said plug portion.

6. A tourniquet release device as claimed in claim 5 with any one of claims 3 or 4, wherein said leg portion comprises a first end pivotally connected to said body, and a second end comprising said suction cup, wherein when in said first condition, said suction cup is temporarily fixed to said substantially flat portion of said body such that said first engaging portion, which is disposed on said leg portion, engages with a corresponding portion on said plug portion in order to prevent the plug portion from disengaging from said first rebate, and when said body is in said second condition, said suction cup is not in suction contact with said substantially flat portion of said body such that said first engaging portion of the leg portion does not engage with said plug portion.

7. A tourniquet release device as claimed in any one of claims 3 to 6, wherein said substantially flat portion of said body comprises said means for allowing for the ingress of air into the interior of said suction cup.

8. A tourniquet release device as claimed in any one of claims 3 to 6, wherein said means for allowing for the ingress of air into the interior of said suction cup comprises an aperture through said substantially flat portion of said body, said aperture defining a channel connecting the interior of the suction cup with the ambient.

9. A tourniquet release device as claimed in any one of claims 3 to 6, wherein said means for allowing for the ingress of air into the interior of said suction cup comprises a groove on said surface of said substantially flat portion of said body, said groove defining a channel connecting the interior of the suction cup with the ambient.

10. A tourniquet release device as claimed in any one of claims 3 to 6, wherein said means for allowing for the ingress of air into the interior of said suction cup comprises an aperture in said suction cup.

11. A tourniquet release device as claimed in any one of claims 5 to 10, wherein said first engaging portion of the leg portion is a raised portion and said corresponding portion on said plug portion is a recess shaped to receive said raised portion.

12. A tourniquet release device as claimed in any one of the previous claims, wherein said tourniquet release device further comprises a visual indicator which becomes visible to a user after said plug portion has been inserted into said first rebate of said body a predetermined number of times.

13. A tourniquet release device as claimed in claim 12, wherein said visual indicator comprises a visual indicator element moveable in a longitudinal direction towards an indicator window, and a rotatable tubular control element, wherein said visual indicator element is moved in a direction towards said indicator window by means of rotation of said tubular control element.

14. A tourniquet release device as claimed in claim 13 with any one of claims 4 to 12, wherein one of said plug portion and said first part of said body comprises a recess inside of which is disposed said tubular control element, said tubular control element being rotatable within said recess in a first sense about a first axis, said tubular control element comprising a first threaded end and a second end comprising a plurality of elongate formations disposed around the periphery of said second end and extending in a direction substantially parallel to said first axis, said tubular control element being substantially prevented from moving in a direction parallel to said first axis, and wherein the other of said plug portion and said first part of said body comprises an elongate engaging member such that when said plug portion is inserted into said first part of said body, a free end of said elongate engaging member engages with at least one said elongate formation to cause said tubular control element to rotate about said first axis in said first sense, wherein said one of said plug portion and said first part of said body further comprises an elongate track extending substantially parallel to said first axis, whereby as said tubular control element rotates, said visual indicator element moves along said track in a direction towards said indicator window, said indicator window being disposed in said one of said plug portion and said first part of said body.

15. A tourniquet release device as claimed in claim 14, wherein at least one said elongate formation is an elongate tooth.

16. A tourniquet release device as claimed in any one of claims 14 or 15, wherein said visual indicator element comprises a substantially planar member having at least one protrusion, said protrusion engaging with said first threaded end of said tubular control element, such that as said tubular control element rotates, said visual indicator element moves along said track in a direction towards said indicator window.

17. A tourniquet release device as claimed in any one of claims 14 to 16, wherein said tubular control element is substantially prevented from rotating in a second sense opposite to said first sense by means of a pawl disposed in said recess and engageable with at least one said elongate tooth, whereby said pawl extends in a direction substantially perpendicular to said first axis.

18. A tourniquet release device as claimed in an one of claims 14 to 117, wherein said free end of said elongate engaging member comprises a rebate at said free end, and said tubular control element is moveable in said recess in a direction substantially perpendicular to said first axis, such that when said plug portion is pulled in a direction such as to remove said plug portion from said first part of said body, said free end of said elongate engaging member engages with at least one said elongate tooth of said tubular control element to cause said tubular control element to move in said direction substantially perpendicular to said first axis so that said tubular control element does not prevent said plug portion from being removed from said first part of said body.

19. A tourniquet release device as claimed in any one of claims 14 to 18, wherein said recess further comprises a biasing member for biasing said tubular control element towards a position whereby said tubular control element prevents said plug portion from being removed from said first part of said body.

20. A tourniquet release device as claimed in claim 19, wherein said biasing member comprises a spring.

21. A tourniquet release device as claimed in any one of the previous claims, further comprising a time indicator which, after actuation by a user, provides a visual indication to a user after a second period of time has elapsed.

22. A tourniquet release device as claimed in claim 21, wherein said time indicator comprises a blister containing a coloured liquid, whereby upon rupture of said blister, said coloured liquid penetrates a porous portion of said tourniquet release device, whereby the extent of penetration of the porous portion by the coloured liquid provides an indication to a user of the time elapsed since the blister was ruptured.

23. A tourniquet release device as claimed in any one of claims 3 to 22, wherein said body further comprises a suction cup release means, said suction cup release means comprising a lever having a free end comprising a lip, wherein depression of said free end of said lever by a user causes the lip to engage with said suction cup and lift it from said substantially flat portion.

24. A tourniquet release device as claimed in any one of claims 3 to 22, wherein said body further comprises a suction cup release means, said suction cup release means comprising a button, wherein depression of said button by a user causes the a portion of the button to engage with said suction cup and lift it from said substantially flat portion.

25. A tourniquet release device as claimed in any one of claims 1 to 3, wherein said first part of said body is a first rebate, wherein when in said first condition, said first portion of said tourniquet strap is prevented from disengaging from said first rebate, and when in said second condition, said first portion of said tourniquet strap is able to disengage from said first rebate, wherein said second portion of said tourniquet strap comprises a plug portion adapted for retention inside said second part, wherein said second part of said body comprises a retention slot for retaining said plug portion of said second portion of said tourniquet strap.

26. A tourniquet release device as claimed in claim 25, wherein said retention slot is adapted so that once said plug portion is inside said retention slot, it cannot be removed.

27. A tourniquet release device as claimed in any one of claims 25 or 26, wherein said body comprises a movable leg portion such that, when said body is in said first condition, said leg portion is engaged with said first portion of said tourniquet strap for said period of time to substantially grip said first portion of said tourniquet strap and substantially prevent it from disengaging from said first rebate, and when said body is in said second condition, said leg portion does not substantially grip said first portion of said tourniquet strap and does not substantially prevent it from disengaging from said first rebate.

28. A tourniquet release device as claimed in claim 27, wherein said leg portion comprises a first end pivotally connected to said body, and a second end comprising a suction cup, such that when said body is in said first condition, said suction cup is temporarily fixed to said substantially flat portion of said body such that said first engaging portion, which is disposed on said leg portion, engages with said first portion of said tourniquet strap to substantially grip said first portion of said tourniquet strap and substantially prevent it from disengaging from said first rebate, and when said body is in said second condition, said suction cup is not in suction contact with said substantially flat portion of said body such that the first engaging portion of the leg portion does not substantially grip said first portion of said tourniquet strap and substantially prevent it from disengaging from said first rebate.

29. A tourniquet release device as claimed in any one of claims 25 to 28 with claim 3, wherein said substantially flat portion of said body comprises said means for allowing for the ingress of air into the interior of said suction cup.

30. A tourniquet release device as claimed in any one of claims 25 to 28 with claim 3, wherein said means for allowing for the ingress of air into the interior of said suction cup comprises an aperture through said substantially flat portion of said body, said aperture defining a channel connecting the interior of the suction cup with the ambient.

31. A tourniquet release device as claimed in any one of claims 25 to 28 with claim 3, wherein said means for allowing for the ingress of air into the interior of said suction cup comprises a groove on said surface of said substantially flat portion of said body, said groove defining a channel connecting the interior of the suction cup with the ambient.

32. A tourniquet release device as claimed in any one of claims 25 to 28 with any one of claims 2 or 3, wherein said means for allowing for the ingress of air into the interior of said suction cup comprises an aperture in said suction cup.

33. A tourniquet release device as claimed in any one of claims 27 to 32 wherein said first engaging portion of said leg portion is a raised portion and said body comprises a corresponding portion in the form of a recess shaped to receive said raised portion, such that when said body is in said first condition, said first portion of said tourniquet strap is gripped between said raised portion and said corresponding portion.

34. A tourniquet release device as claimed in any one of the previous claims, wherein said body comprises a biasing means, for biasing said body towards the second condition.

35. A tourniquet release device as claimed in claim 34, wherein said biasing means is a spring member.

36. A tourniquet release device for releasing a tourniquet strap from a limb of a patient after a period of time, substantially as hereinbefore described with reference to the accompanying drawings.

3 7. A tourniquet comprising: - a strap a retention and release device according to any of the preceding claims.