BLOOD OCCLUSION OR RESTRICTION CUFF

Abstract

A remotely operated blood flow occlusion or restriction cuff for use as a muscle building device or a compact medical emergency reperfusion tourniquet. A module on the cuff housing an air pump, a controller operating the air pump and power supply. The inflation and deflation of the cuff controlled using a smart device in communication with the controller. In the preferred embodiment this is via a Smartphone app and Bluetooth protocol. The tourniquet operating in conjunction with a Doppler ultrasound and/or pulse oximeter to monitor arterial inflow.

Claims

1. A remote controlled blood flow restriction cuff comprising: an air bladder configured to be positioned around a limb; a compact air pump located on the cuff to pressurise the air bladder; a pressure sensor to sense bladder air pressure; an electronic controller to control operation of the air pump; the controller adjustable for a predetermined pressure or pressure range, and receptive and responsive to signals from the pressure sensor; a power supply located on the cuff to provide power to the air pump, controller and pressure sensor, and wherein inflation and deflation of the cuff can be controlled using a remote device in communication with the controller.

2. The restriction cuff according to claim 1 wherein the controller enables the cuff to be inflated to and retained at a pressure up to 350 mmHg.

3. The restriction cuff according to claim 1 wherein the air pump is a battery operated air pump.

4. The restriction cuff according to claim 1 wherein the power supply is a rechargeable battery power supply.

5. The restriction cuff according to claim 1 wherein 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.

6. The restriction cuff according to claim 1 wherein, the operation of the cuff is controlled remotely over a wireless protocol such as Bluetooth, associated with a Smart computer or phone application (app).

7. The restriction cuff according to claim 1 wherein the pressure sensor detects pressure in the cuff which is maintained at the predetermined pressure level by the controller operating the air pump responsive to signals from the pressure sensor.

8. The restriction cuff according to claim 1 wherein the controller receptive to signals from the pressure sensor accounts for variance in pressure due to limb movement.

9. The restriction cuff according to claim 1 wherein the cuff is positioned around a limb by a releasable fastening means.

10. The restriction cuff according to claim 1 wherein the wherein, the operation of the cuff is controlled with a smart phone application (app) and wherein the app includes customised programs for muscle building and strength, a timer, pressure controls, emergency stop, and tracks relevant physiological data with ability to store exercise variable data such as repetitions, sets and pressure history.

11. The restriction cuff according to claim 1 used as a medical tourniquet which allows pressure to be electronically increased and decreased via a smart phone application, wherein pressure is set at a desired level, and the pressure sensor and air pump make micro adjustments to keep cuff pressure constant at the desired level.

12. The restriction cuff according to claim 1 worn on a proximal upper limb (e.g. upper arm) and a proximal lower limb (e.g. upper thigh).

13. The restriction cuff according to claim 1 wherein the cuff is a leather or nylon or silicone 5 or 10 cm cuff with a ratchet or buckle or loop Velcro fastening system.

14. A method of using a remote controlled blood flow restriction cuff to build and/or strengthen muscle including the steps of a) applying the cuff to a limb; b) initialising and connecting the cuff via a remote device or a Bluetooth protocol Smartphone application (app); c) when connected, a user in response to a pre exercise questionnaire, inputs through the app, 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; d) the user selects the most appropriate training program and range of cuff pressures expressed in mmHg; e) the user sets a timer for the selected training program; f) the user presses a start button of the remote device or the app; g) the cuff inflates to a desired pressure; h) the cuff through an electronic controller in response to a pressure sensor controlling an air pump maintains pressure at a specified range of cuff pressures, by inflating and deflating the cuff as necessary to account for limb movement; i) once the timer has expired or the user stops the program, the cuff deflates, and j) the Smartphone application records cuff pressures and duration in a user profile wherein data stored allows the user to generate training programs based upon the physiological data and stored cuff pressure data, as well as enabling the user to log sets and repetitions whereby the user can use the app for other wellness parameter tracking.

15. A method of using a remote controlled blood flow restriction cuff as a medical tourniquet including the steps of: a) applying the cuff to an injured limb; b) initialising the cuff operation via a remote device or a Bluetooth protocol Smartphone application (app); c) monitoring arterial inflow via Doppler ultrasound; d) increasing cuff pressure, via the device or app, to an arterial occluding pressure indicated by the Doppler signal; e) automatically maintaining arterial occluding cuff pressure measured by the pressure sensor and also inflating or deflating the cuff in response to the Doppler signal; f) rating the level of traumatic injury to a limb via the remote device or app, wherein a reperfusion program is selected to automatically allow brief periods of cuff deflation and re-inflation for reperfusion of the limb thereby mitigating risk of unnecessary hypoxic tissue damage; g) monitoring arterial inflow via the Doppler ultrasound 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, wherein h) once full medical or hospital intervention can be provided, the cuff can then be deflated and removed under medical supervision.

16. The method of claim 15 including the step of using a pulse oximeter in the alternative, or in conjunction with, the Doppler ultrasound to monitor the arterial inflow.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0091] Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

[0092] FIGS. 1 to 4 show various views of a preferred blood flow restriction cuff in accordance with the invention.

[0093] FIG. 5 shows the embodiment of FIGS. 1 to 4 in use as an exercise cuff.

[0094] FIG. 6 shows the embodiment of FIGS. 1 to 4 in use as a medical tourniquet.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0095] FIGS. 1 to 4 show views of a preferred remote controlled blood flow restriction cuff 10 according to the invention. Cuff 10 is configured to be positioned around a limb (not shown). Compact air pump 14 in module 15 pressurises the air bladder (not visible as sewn inside the cuff) via tube 13 connected to valve 17 which supplies air to the bladder through air inlet 12. Pressure sensor 16 on PCB board 19 senses the air pressure in the air bladder (not visible as sewn inside the cuff). Microprocessor based electronic controller 18 on PCB board 19 with reset button 21 and reset switch 21a controls operation of the air pump 14 and is adjustable for a predetermined pressure or pressure range. Microprocessor controller 18 is receptive and responsive to signals received from pressure sensor 16.

[0096] Power supply 20 is located on the cuff to power the air pump 14 and the controller 18, 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 18.

[0097] As previously mentioned preferably, controller 18 enables the cuff to be inflated to and retained at a pressure up to 350 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 14 is battery operated and power supply 20 is a rechargeable battery power supply.

[0098] As is shown, air pump 14, power supply 20, pressure sensor 16, and controller 18 are housed in a module 22 on cuff 10.

[0099] In the preferred embodiment, operation of the cuff 10 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 23.

[0100] Preferably, pressure sensor 16 detects pressure to the nearest 1 mmHg, wherein pressure in the air bladder is maintained at the predetermined pressure level by controller 18 operating the air pump 14 responsive to signals from pressure sensor 16.

[0101] Suitably, controller 18 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 25 shows that the power supply 20 has been turned on.

[0102] FIG. 5 shows the embodiment of FIGS. 1 to 4 in use as training cuffs 10 to build and strengthen muscle, in this case, the upper arms 30, 32 by lifting dumbbells 60, 62.

[0103] The cuffs 10 are applied to the upper arms 30, 32. User 40 initialises and connects with the controller of the cuff via a smartphone 50 with an application (app) 52 running on a Bluetooth protocol.

[0104] When connected, the user 40 in response to a pre exercise questionnaire, inputs through the app 52, 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.

[0105] The user 40 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 53 displayed by the app.

[0106] The cuffs 10 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.

[0107] Once the timer has expired or the user stops the program, the cuff deflates, and Smartphone app 52 records cuff pressures and duration in a user profile.

[0108] 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.

[0109] FIG. 6 shows the embodiment of FIGS. 1 to 4 in use as a medical tourniquet.

[0110] Cuff 10 is applied to an injured limb 65 with a wound dressed by bandage 67. A user initialises and connects with the controller of the cuff via a smartphone 70 with an application (app) 72 running on a Bluetooth protocol. Arterial inflow to the limb 65 is monitored via a Doppler ultrasound pickup 74. 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.

[0111] 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.

[0112] 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 76 can also be used to monitor blood oxygen saturation and heartrate.

[0113] Once full medical or hospital intervention can be provided, the cuff can then be deflated and removed under medical supervision.

[0114] 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.

[0115] Continuous wave Doppler ultrasound has the following main function:

[0116] 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.

[0117] A pulse oximeter has two main functions, which are as follows:

[0118] 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.

[0119] 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.

[0120] The following include examples of procedures which can be adopted in the use of the invention.

[0121] 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.

Stage 1Measuring Upper Limb Pressure Using the Pulse Oximeter.

[0122] Place an appropriate size blood-pressure cuff around the patient's upper arm;

[0123] Place the pulse oximeter sensor on any finger (FIG. 1a). When the sensor is placed on the digit, the oximeter will display two numbers: the first represents the patient's heart rate, the second the percentage of circulating oxygenated haemoglobin. Pulse blood flow is also displayed on the oximeter, either by a waveform or by a column of lights;

[0124] Record a baseline reading. Inflate the cuff to 60 mmHg, then inflate it in 10 mmHg increments, allowing approximately 10 seconds between these increments. Once the pressure reaches 100 mmHg, the incremental changes can be increased to 20 mmHg;

[0125] Record the pressure reading that is one below the point where the audible or pulse signal is lost on the pulse oximeter; for example, if the signal is lost at 180 mmHg, record a pressure of 160 mm Hg;

[0126] Repeat the measurement on the other arm, then calculate the Limb Occlusion Pressure by using the higher of the two readings

Stage 2Measuring Lower Limb Pressure Using the Pulse Oximeter.

[0127] Place an appropriate size cuff around the largest most proximal thigh region.

[0128] Place the oximeter sensor on one of the first three toes (FIG. 1b).

[0129] Inflate the cuff as outlined in Stage 1, 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.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] It is worn on the upper and lower limbs. Preferably, the cuffs are 5 cm or 10 cm 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 25 cm to 50 cm length and for a lower limb is 50 to 75 cm length.

[0134] 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 0-350 mmHg and maintains the set pressure for the duration of use.

[0135] 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.

[0136] 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.

[0137] 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.

[0138] 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.

[0139] It will be apparent that obvious variations or modifications may be made which are in accordance with the spirit of the invention and which are intended to be part of the invention, and any such obvious variations or modifications are therefore within the scope of the invention.

REFERENCES

[0140] Abe, T., Yasuda, T., Midorikawa, T., Sato, Y., Kearns, C. F., Inoue, K., & Ishii, N. (2005a). Skeletal muscle size and circulating IGF-1 are increased after two weeks of twice daily KAATSU resistance training. International Journal of KAATSU Training Research, 1(1), 6-12. [0141] Loenneke, J. P., Wilson, G. J., & Wilson, J. M. (2010). A mechanistic approach to blood flow occlusion. Int J Sports Med, 31(1), 1-4. [0142] Peterson, M. D., Pistilli, E., Haff, G. G., Hoffman, E. P., & Gordon, P. M. (2011). Progression of volume load and muscular adaptation during resistance exercise. European journal of applied physiology, 111(6), 1063-1071. [0143] Estimation of limb occlusion pressure for surgical tourniquets based on the measurement of Arterial Pulse Wave Transit Time. Marko, Alexei John. 1994. Vancouver: University of British Columbia Library.