Patent Description:
Furthermore, the invention can be used as a self-contained and wireless medical tourniquet to prevent critical blood loss and hypoxic tissue damage in emergency and traumatic life threatening situations.

The improvement of the invention is directed to removing the necessity of various inflation tubes and electrical cables associated with prior art cuffs and tourniquets, which not only restrict movement during training, but also require ancillary equipment such as external air pumps and monitoring devices required for their operation.

While the invention is directed to an improved self-contained cuff and tourniquet which dispenses with the requirement of lines, tubing or equipment currently associated with such devices, it is instructive to examine their present use and the state of the prior art.

According to conventional theory, to induce muscular hypertrophy, lifting weights with a minimum of <NUM>% of one repetition maximum tests (1RM) is needed. It is accepted that intensities below this threshold lack the essential stimulus to produce muscular adaptations in the sarcoplasms and myofibrillars of muscle tissue (Peterson et al <NUM>). Recent studies, however, using relatively low loads of predicted 1RM as low as <NUM>% combined with blood flow restriction (BFR) have been effective in eliciting muscular hypertrophy and strength similar to that achieved with higher loads (Abe et al <NUM>).

Prior art blood flow restriction training is a muscular hypertrophy and strength stimulus utilising the application of specially adapted pressure cuffs to the top of a limb e.g. an upper thigh and/or arm which are inflated to a predetermined pressure throughout the duration of the exercise (Abe et al <NUM>, Loenneke <NUM>). The pressure applied to the limb is strong enough to partially restrict the venous return of blood from peripheral muscle beds to the heart, but not strong enough to occlude arterial blood supply to the muscle region (Abe et al <NUM>, Loenneke <NUM>).

Blood flow restriction (BFR) training should not be confused with training under ischemic conditions. BFR does not induce ischemia within skeletal muscle, but rather promotes a state of blood pooling in the capillaries within the limb musculature as venous return is only slightly impaired and muscle bed perfusion under mean arterial pressure is maintained throughout the training load or exercise regimen (Abe et al <NUM>).

The use of medical tourniquets is widely documented. In Outpatient clinics, where it is less critical, tourniquets usually comprise elastic or other manually operated bands. They do not allow for accurate pressure levels to be established and are used merely to occlude venous return or in the extreme, arterial blood supply to a limb to control blood loss. These simple occlusion cuffs, often connected to an analogue gauge, usually portable, comprise a hand operated pump which inflates an air cuff. While this is a basic, portable and low cost device, it cannot be used to accurately monitor the perfusion of a muscle bed. Simpler devices, such as blood flow restriction (BFR) bands, usually comprise elastic material to restrict blood flow. They are cheap and versatile but cannot gauge or retain pressure and invariably are not associated with monitoring systems.

In the intensive treatment of patients, where control of the circulatory system is vital, machine operated tourniquets connected to digital pressure monitors and pumps, allow for pressure to be accurately applied by controlled inflation of cuffs which impede blood flow. This is especially important where reperfusion of a damaged limb needs to occur periodically. Such tourniquets have to be programmed to deflate regularly to allow arterial inflow into the affected area to help mitigated the risk of tissue damage from hypoxia. Such prior art reperfusion tourniquets are generally associated with separate pump and control modules found more commonly in the accident and emergency (A & E) or intensive care units (ICU) of hospitals.

Relevant prior art medical tourniquets include the Kaatsu tourniquet, which is used widely in Japan, and comprises a machine with an electronic monitor system connected to air cuffs via plastic tubing. While it has the advantage of an electronic monitor which is relatively portable and accurate, it has external tubing, and therefore not ideal for dynamic exercise or mobile use. The Delphi Blood flow restriction cuff is a digital machine, connected to an intravenous (IV) pole with plastic tubing connected to an air cuff. It can monitor pressure applied to a limb accurately but is expensive, cumbersome, not portable, and needs to be connected to a mains power source. It also requires the use of external tubing which compromises the user's mobility and/or freedom of movement.

<CIT> discloses a belt having a gas bag and configured to impart to the specific portion a pressurizing force based on the amount of gas in the gas bag in a state of being wrapped around a specific part of the user's limb; configured to control a pressurizing force applied by the belt to the specific portion by controlling a supply amount and a discharge amount of the gas to the gas bag of the belt based on the control command and a portable information terminal device configured to wirelessly communicate the control command to the control device when operated in a predetermined manner.

<CIT> discloses a muscle training method, comprising the following steps that are repeated alternately to perform training of a muscle of a user: a pressuring and exercise step of winding a belt around at least one of four limbs of the user and applying specific pressure thereto so as to restrict blood circulation of the muscle of the user without stopping the blood circulation, and asking the user to perform load-applied exercise to apply load of specific weight to the muscle of the user; and an exercise stopping step of asking the user to stop the load-applied exercise while continuously applying the specific pressure to the user, wherein the specific weight is set at a value smaller than maximum weight necessary for the user to exert maximum muscle force.

<CIT> discloses system and a method for controlling blood flow through a zone of a patient limb, the zone being bounded by a proximal end and a distal end. The system comprises a cuff configured for securing to the limb and for covering the zone, the cuff being inflatable to provide pressure to the zone for occluding the flow of blood flowing through the zone in the direction from the proximal to distal ends of the zone, an array of sensors fitting between the cuff and the limb and arranged for sensing and signalling a distance from the proximal end that the arterial blood flow penetrates into the zone; and a control instrument connected to the array and to the cuff for regulating the pressure in the cuff to occlude the blood flow in the zone depending upon the arterial blood flow penetration distance signalled by the array; and an inflatable auxiliary bladder disposed adjacent to the array and inflatable independently from the cuff for varying an angular position of the sensors of the array relative to the limb while the zone is covered with the inflatable cuff secured to the limb to provide pressure to the zone, thereby to scan various tissue volumes.

<CIT> discloses apparatuses and methods for monitoring the cardiac health of a patient, which incorporates secondary information. The apparatus may be a heart rate monitor, a blood pressure monitor, an ECG or other biometric device in communication with an electronic device having communication ability. The devices detect a cardiac or other biometric measurement and correlate the detected information with secondary information, such as GPS data, to produce a contextualized measurement.

<CIT> discloses a limb occlusion device capable of performing more than one function, for example as a limb occlusion tourniquet, as a blood pressure monitor and as a device for automatic delivery of remote conditioning treatment.

<CIT> discloses methods and devices for delivery of a remote ischemic conditioning treatment. The device comprises a cuff configured for placement over the limb of the subject and a controller operably connected to said cuff, wherein said cuff is further configured to at least partially reduce blood flow in said limb upon inflation thereof.

It is therefore an advantage to provide a versatile venous restriction or occlusion cuff without any attached tubing or cables for use in muscular strength and hypertrophy training, but which can also be used as an arterial reperfusion tourniquet to stop traumatic blood loss without tissue hypoxia at increased cuff pressures.

It is also an advantage that the invention is a standalone and relatively compact apparatus which allows for greater user mobility while training and which reduces the amount of space taken up in storage or transport.

Importantly, the invention seeks to provide the public with a commercial alternative and useful improvement over the prior art.

The invention is set forth in the independent claims. Embodiments result from the dependent claims and the below description.

In one aspect therefore, the invention resides in a remote controlled blood flow restriction cuff as defined in independent claim <NUM>.

Preferably, the controller enables the cuff to be inflated to and retained at a pressure up to <NUM> mmHg. It will be obvious that an inflation pressure above that of a systolic pressure of a wearer will facilitate the cuff to be used as medical tourniquet to stop blood flow.

Preferably, the air pump is a battery operated air pump.

Preferably, the power supply is a rechargeable battery power supply.

Preferably, the air pump, power supply, pressure sensor, and controller are housed in a module proximal to the air bladder, which are all located on the cuff.

Preferably, the operation of the cuff is controlled remotely over a wireless protocol such as Bluetooth, associated with a Smart computer or phone application or other equivalent system.

Preferably, the pressure sensor detects pressure to the nearest <NUM> mmHg, wherein pressure in the cuff is maintained at the predetermined pressure level by the wireless controller operating the air pump responsive to signals from the pressure sensor.

Suitably, the controller accounts for variance in pressure due to limb movement for the duration required until the pressure is released from the cuff.

In another aspect, the invention resides in a method of using a remote controlled blood flow restriction cuff as defined in independent claim <NUM>.

Suitably, where available or desired, a pulse oximeter can be used in the alternative or in conjunction with a Doppler ultrasound to monitor arterial inflow.

It will be obvious, the advantage of using oximetry would be a readily obtainable pulse rate and a blood oxygen saturation level.

The present disclosure provides a digital tourniquet device with no external wires or tubing, and is a fully self-enclosed pneumatic air cuff. They are designed to be used as medical tourniquets during trauma events to stop blood flow and to be used in fitness during blood flow restriction training.

They are blood flow restriction devices which are digital, wireless, and pneumatic cuffs, to be worn on the upper limbs and lower limbs. The blood flow restriction or occlusion device of the present invention is electronic, completely wireless and tubeless design that includes an integrated power supply. The device is self-contained, but interacts with an untethered controller that is adapted to be worn on the limbs of a user.

The device measures individualised pressure zones of a user, which are based on personalised physiological data, and maintains a restriction pressure that is exerted upon the limb, which is applied consistently in real time, and accounts for movement of limb. This means that the device makes adjustments to increase/decrease pressure in order to maintain the preselected pressure in accordance with the individualised pressure zone of the user.

The physiological data can include blood flow, pulse rate, blood pressure, limb occlusion pressure (LOP) and arterial occlusion pressure (AOP). The physiological data for blood flow and pulse rate are collected via the following methods, which can be determined by integrated and off the shelf devices coupled with smartphone apps;.

Arterial occlusion pressure (AOP) is a measure of the cuff pressure required to maintain a bloodless surgical field.

Limb occlusion pressure or LOP can be defined as the minimum pressure required to stop the flow of arterial blood into the limb distal to the cuff. LOP is determined by gradually increasing tourniquet pressure until distal blood flow is interrupted.

The risk of tourniquet related complications can be significantly reduced by measuring the LOP and selecting cuff inflation pressures accordingly. Best practice recommends that optimal cuff pressure should be based on the patient's LOP. The tourniquet pressure should be minimized, lower pressures are thought to prevent injury of normal tissue.

The device of the present invention calculates the limb occlusion pressure (LOP) in accordance with the following steps :-.

Individual limb occlusion pressure will be measured manually by (a) palpation, and (b) Doppler ultrasound (c) using a distal photo plethysmography sensor (d) NIRS(e) bio impedance.

Tourniquet cuff is automatically inflated and utilizes aforementioned probes to detect arterial pulsations in limb at level of cuff and distal to the tourniquet cuff.

When measured correctly in applying LOP in BFR using surgical grade automated devices, LOP helps in delivering optimum results in rehabilitation by personalizing blood flor restriction training for rehabilitation of elderly, improving performance of injured athletes and in patients recovering from major surgical procedures such as knee arthroscopy.

The devices of the present invention are inflated to a pressure of between <NUM>-350mmhg. There is an on-board module housing the battery operated air pump. The on-board pressure sensor or monitor detects the desired pressure to the nearest 1mmHg. Pressure is maintained at a desired pressure level for the duration needed and is corrected for variance in pressure with limb movement. Pressure is then released by the user. The device is preferably controlled via Bluetooth or wireless controller with accompanying Smartphone application. The devices are to be used in conjunction with and without low load resistance training to increase muscular size and strength comparatively to exercising with higher loads.

Exercising at necessary intensity can cause injury, and people who would benefit most from exercise often cannot participate e.g. injured or sick patients. Typically, to achieve positive muscular adaptations, individuals have to exercise at above <NUM>% of their maximum level. According to literature, however, when low load exercise of <NUM>-<NUM>% of maximum is combined with blood flow restriction, the same results to non-blood restriction training can be achieved in comparative time frames.

Currently on the market, there exists two extreme versions of the prior art. These include cumbersome, wired, heavy, medical devices, which are not portable and easily used, or expensive elastic tourniquets, which are not accurate and offer no physiological data, and which are prone to abuse by over tightening.

<FIG> show views of a preferred remote controlled blood flow restriction cuff <NUM> according to the invention. Cuff <NUM> is configured to be positioned around a limb (not shown). Compact air pump <NUM> in module <NUM> pressurises the air bladder (not visible as sewn inside the cuff) via tube <NUM> connected to valve <NUM> which supplies air to the bladder through air inlet <NUM>. Pressure sensor <NUM> on PCB board <NUM> senses the air pressure in the air bladder (not visible as sewn inside the cuff). Microprocessor based electronic controller <NUM> on PCB board <NUM> with reset button <NUM> and reset switch 21a controls operation of the air pump <NUM> and is adjustable for a predetermined pressure or pressure range. Microprocessor controller <NUM> is receptive and responsive to signals received from pressure sensor <NUM>.

Power supply <NUM> is located on the cuff to power the air pump <NUM> and the controller <NUM>, wherein inflation and deflation of the air bladder is controlled using a remote device such as a Smartphone (not shown) in communication with the controller <NUM>.

As previously mentioned preferably, controller <NUM> enables the cuff to be inflated to and retained at a pressure up to <NUM> mmHg. Which will be an inflation pressure above that of systolic pressure of most users which will also facilitate the cuff to be used as medical tourniquet to stop arterial blood loss. Air pump <NUM> is battery operated and power supply <NUM> is a rechargeable battery power supply.

As is shown, air pump <NUM>, power supply <NUM>, pressure sensor <NUM>, and controller <NUM> are housed in a module <NUM> on cuff <NUM>.

In the preferred embodiment, operation of the cuff <NUM> is controlled remotely over a wireless protocol such as Bluetooth, associated with a Smart computer or phone application or other equivalent wireless system for example a USB programmed memory stick (not shown) inserted in USB port <NUM>.

Preferably, pressure sensor <NUM> detects pressure to the nearest 1mmHg, wherein pressure in the air bladder is maintained at the predetermined pressure level by controller <NUM> operating the air pump <NUM> responsive to signals from pressure sensor <NUM>.

Suitably, controller <NUM> accounts for variance in pressure due to limb movement for the duration required until the pressure is released from the air bladder. Circular LED light <NUM> shows that the power supply <NUM> has been turned on.

<FIG> shows the embodiment of <FIG> in use as training cuffs <NUM> to build and strengthen muscle, in this case, the upper arms <NUM>, <NUM> by lifting dumbbells <NUM>, <NUM>.

The cuffs <NUM> are applied to the upper arms <NUM>, <NUM>. User <NUM> initialises and connects with the controller of the cuff via a smartphone <NUM> with an application (app) <NUM> running on a Bluetooth protocol.

When connected, the user <NUM> in response to a pre exercise questionnaire, inputs through the app <NUM>, physiological data, age, height, medical history, gender, limb circumference size, body fat level, heart rate and blood pressure and any other requisite pre exercise information required.

The user <NUM> then selects the most appropriate training program and a range of cuff pressures and sets a timer for the selected training program. The user presses a start button <NUM> displayed by the app.

The cuffs <NUM> inflate to the desired pressure and through the electronic controller in response to a pressure sensor controls the air pump which maintains pressure by inflating and deflating the cuff as necessary to account for any limb movement.

Once the timer has expired or the user stops the program, the cuff deflates, and Smartphone app <NUM> records cuff pressures and duration in a user profile.

As the smart phone application monitors physiological data continuously and wirelessly via Bluetooth (arterial inflow, pulse rate and oxygen saturation) this physiological data is put through an algorithm in conjunction with age, weight, limb circumference, and lean fat-free mass. This information is used to create a personalised user profile to establish the safest pressure parameters as a percentage of 'Limb Occlusion Pressure' and is customised to each user's needs as a hypertrophy/strength inducing blood flow restriction training device or as a life preserving medical tourniquet device (see below). In the training environment, the smart phone application will store data per session, pressure used, duration, and physiological data which can be used to create a customised user blood flow restriction exercise program.

<FIG> shows the embodiment of <FIG> in use as a medical tourniquet.

Cuff <NUM> is applied to an injured limb <NUM> with a wound dressed by bandage <NUM>. A user initialises and connects with the controller of the cuff via a smartphone <NUM> with an application (app) <NUM> running on a Bluetooth protocol. Arterial inflow to the limb <NUM> is monitored via a Doppler ultrasound pickup <NUM>. The user then increases cuff pressure, via the app, to an arterial occluding pressure indicated by the attenuation of the Doppler signal. The controller automatically maintains the arterial occluding cuff pressure measured by the pressure sensor by inflating or deflating the cuff in response to the Doppler signal.

The user rates the level of traumatic injury to a limb via the app, wherein a reperfusion program is selected to instruct the controller to enable brief periods of cuff deflation and re-inflation for reperfusion of the limb thereby mitigating the risk of unnecessary hypoxic tissue damage.

The controller monitors arterial inflow wherein the cuff is only deflated and re-inflated in response to the Doppler signal to minimise blood loss in accordance with the reperfusion program. A digital pulse oximeter <NUM> can also be used to monitor blood oxygen saturation and heartrate.

Once full medical or hospital intervention can be provided, the cuff can then be deflated and removed under medical supervision.

The medical tourniquet cuff and application utilises a smart phone or wireless interface display unit driven system of blood flow restriction achieved by using completely self-contained digital air pneumatic cuffs to impede venous arterial return through a self-regulating pressure sensor including blood flow restriction or occlusion monitoring via continuous wave Doppler ultrasound and/or pulse oximetry.

Continuous wave Doppler ultrasound has the following main function:
By sending and receiving ultrasound waves through the skin located over an artery or heart, when the waves are reflected from a moving object, such as blood passing through an artery, the reflected frequency changes slightly. This change is then analysed by the electronics of the Doppler ultrasound unit and converted into a digital display of the cardiac output and heart rate.

A pulse oximeter has two main functions, which are as follows:
To provide an audible signal of pulsed blood flow, similar to that of a Doppler ultrasound. When an artery is occluded by a pressure cuff, there is a loss of signal from the oximeter; and to measure the oxygen saturation of haemoglobin in blood or tissue.

Continuous wave Doppler ultrasound and the pulse oximetry are used in the measurement of pulse wave transit time distal to position of the cuff on the limb. Pulse wave transit time is defined as the time required for an arterial pulse wave to propagate along a fixed path, which is used to determine 'Limb Occlusion Pressure'. This measurement can be made by monitoring the pulse at a point distal to the application point of the tourniquet. Once the distal pulse rate is absent at the most minimal arterial pressure, this is determined to be the 'Limb Occlusion Pressure'.

The following include examples of procedures which can be adopted in the use of the invention.

First time use and creation of personalised Smartphone Application User Profile.

Explain the procedure to the patient;
Ensure he/she is lying comfortably in a semi-recumbent position.

Place an appropriate size blood-pressure cuff around the patient's upper arm;.

Place an appropriate size cuff around the largest most proximal thigh region.

Place the oximeter sensor on one of the first three toes (Fig 1b).

Inflate the cuff as outlined in Stage <NUM>, and record the pressure at which the signal is lost.

Repeat the measurement on the other leg, then calculate the 'Limb Occlusion Pressure' index by using the higher of the two readings.

The pressure at which the arterial pulse is stopped corresponds to the minimum tourniquet cuff pressure to occlude the underlying arteries or 'Limb Occlusion Pressure' at that time.

After the 'Limb Occlusion Pressure' is identified, this data is fed through the accompanying Smartphone application. Working pressures for blood flow restriction are personalised using the 'Limb Occlusion Pressure' data gathered. Each user's physiological details are stored in the Smartphone application. The micro processer (or controller) and the pressure sensor/pump implements the calculated pressure target as a percentage of the 'Limb Occlusion Pressure'. This personalised approach ensures only the most minimal blood impedance pressures are applied, helping to mitigate the risks associated with tourniquet application. This ensures arterial inflow into a limb but restricts venous return, which leads to a cascade of physiological benefits as earlier mentioned.

The present invention allows individuals to engage in blood flow restriction training more safely and accurately. It has all the safety and physiological data of expensive wired medical devices but with the added freedom of having all electronics housed in an on-board module with no external tubing or wiring.

It is worn on the upper and lower limbs. Preferably, the cuffs are <NUM> or <NUM> wide pneumatic cuffs comprising of an outer cuff material of leather or silicone with airbag contained between the material layers. The cuffs are preferably applied using a ratchet or buckle or Velcro loop fastening system. The pneumatic cuff for an upper limb is <NUM> to <NUM> length and for a lower limb is <NUM> to <NUM> length.

The airbag is connected to the module unit with a two way valve which can be closed to allow pressure to be held and maintained at a desired pressure level with the pressure sensor and controller maintaining this pressure irrespective of limb movement by making small adjustments in air pressure to allow maintenance of the desired pressure. The cuff module contains an on-board battery, pressure sensor and air pump all housed in a plastic casing which allows the airbag to be inflated and to increase pressure (mmHg) in the airbag. This increase in pressure in mediated by the on-board sensor which increases pressure to a predetermined level between <NUM>-<NUM> mmHg and maintains the set pressure for the duration of use.

The system then allows pressure to be released when desired by the user. Communication with the device is via Bluetooth or an equivalent wireless protocol. The device will have accompanying smart phone application or a wireless remote control unit. There is no external tubing or wiring. The device is completely free and is only attached to a limb by the releasable fastening system.

In summary, the invention can be described as a wireless operated tubeless air pneumatic cuff system with a dual purpose role in blood flow restriction training and as a portable tourniquet for medical emergencies. As a wireless operated tourniquet, it enables pressure exerted on limb to be maintained at a desired level through an inbuilt pressure sensor and controller. The main advantage of the device is that it is completely wireless, portable and self-contained without requiring extraneous tubing connected to ancillary equipment. All electronics and the air bladder are encased within the cuff itself. The device has application in the medical field by being used as a digital medical tourniquet to stop traumatic blood loss at higher cuff pressures as well as in the fitness industry in conjunction with low load resistance training to increase muscle strength and hypertrophy.

It is conveniently operated via a Smartphone application which reacts to physiological data including arterial pulse rate and blood oxygen saturation levels to create a user profile which can then be programmed to automatically control occlusion pressure levels according to customised training protocols.

In this specification, unless the context clearly indicates otherwise, the term "comprising" has the non-exclusive meaning of the word, in the sense of "including at least" rather than the exclusive meaning in the sense of "consisting only of". The same applies with corresponding grammatical changes to other forms of the word such as "comprise", "comprises" and so on.

Claim 1:
A remote controlled blood flow restriction cuff (<NUM>) comprising:
an air bladder configured to be positioned around a limb;
a compact air pump (<NUM>) located on the cuff (<NUM>) to pressurize the air bladder;
a pressure sensor (<NUM>) to sense bladder air pressure;
an electronic controller (<NUM>) to control operation of the air pump (<NUM>); the controller (<NUM>) adjustable for a predetermined pressure or pressure range, and receptive and responsive to signals from the pressure sensor (<NUM>);
a power supply (<NUM>) located on the cuff to provide power to the air pump (<NUM>), controller (<NUM>) and pressure sensor (<NUM>);
wherein inflation and deflation of the cuff can be controlled using a remote device in communication with the controller
wherein the electronic controller (<NUM>) is configured to:
inflate the cuff (<NUM>) in small increments until pulse stops;
sense at what pressure level pulse rate is no longer detected using photoplethysmography, bioimpedance, near infrared spectroscopy and/or Doppler ultrasound,
determine a limb occlusion pressure (LOP) of a user as the point at which minimal pressure is required to stop blood flow to an extremity of the limb;
inflate the cuff (<NUM>) to a desired percentage of LOP between <NUM>-<NUM>% based on a user selection; and
to maintain the pressure at the selected percentage of LOP, keeping pressure constant in this zone allowing for adjustments with limb/body movement.