A traditional tourniquet system: the tourniquet itself and a wooden stick.

A primitive tourniquet can be made from a stick and a rope (or leather belt). The rope is made into a loop that fits over the damaged limb and the stick is inserted through the loop. The loop is tightened by twisting the stick. The primitive device may stem the flow of blood but side-effects such as soft tissue damage and nerve damage may occur due to the application of unknown, uncontrollable and excessively high pressures and pressure gradients. It is well established by evidence in the clinical literature that higher tourniquet pressures are associated with higher probabilities of tourniquet-related injuries.^[1][2] Modern pneumatic tourniquet systems are microcomputer-based, allowing more accurate and automatic pressure control and many important safety features to minimize the risk of patient injury. Recent trends toward personalized care has increased patient safety by allowing perioperative staff to measure and select a personalized tourniquet pressure based on the patient’s Limb Occlusion Pressure, and select and apply a personalized tourniquet cuff that can adapt the shape of the tourniquet cuff to a wide range of non-cylindrical limb shapes.^[3]

History[edit]

Petit tourniquet engraving from 1798

During Alexander the Great’s military campaigns in the fourth century BC, tourniquets were used to stanch the bleeding of wounded soldiers.^[4]Romans used them to control bleeding, especially during amputations. These tourniquets were narrow straps made of bronze, using only leather for comfort.^[5]

In 1718, French surgeon Jean Louis Petit developed a screw device for occluding blood flow in surgical sites. Before this invention, the tourniquet was a simple garrot, tightened by twisting a rod (thus its name tourniquet, from tourner = to turn).

In 1785 Sir Gilbert Blane advocated that, in battle, each Royal Navy sailor should carry a tourniquet:

Sir Gilbert Blane advocates the issue of a tourniquet to each man in battle.

“It frequently happens that men bleed to death before assistance can be procured, or lose so much blood as not to be able to go through an operation. In order to prevent this, it has been proposed, and on some occasions practised, to make each man carry about him a garter, or piece of rope yarn, in order to bind up a limb in case of profuse bleeding. If it be objected, that this, from its solemnity may be apt to intimidate common men, officers at least should make use of some precaution, especially as many of them, and those of the highest rank, are stationed on the quarter deck, which is one of the most exposed situations, and far removed from the cockpit, where the surgeon and his assistants are placed. This was the cause of the death of my friend Captain Bayne, of the Alfred, who having had his knee so shattered with round shot that it was necessary to amputate the limb, expired under the operation, in consequence of the weakness induced by loss of blood in carrying him so far. As the Admiral on these occasions allowed me the honour of being at his side, I carried in my pocket several tourniquets of a simple construction, in case that accidents to any person on the quarter deck should have required their use.”^[6]

Joseph Lister is credited for being the first to use a tourniquet device to create a bloodless surgical field in 1864. He also recommended exsanguinations prior to tourniquet application by limb elevation. In 1873, Friedrich von Esmarch developed a rubber bandage that would both control bleeding and exsanguinate. This device is known as Esmarch's bandage for surgical haemostasis or Eschmarch's Tourniquet. At the time this device was superior to Petit’s device because Petit’s cloth bandages tore, the screw could untwist, and pressures that were very high, unknown and uneven were applied to the underlying limb, resulting in hazards and injuries. In 1881, Richard von Volkmann showed that limb paralysis can occur from the use of the Esmarch tourniquet. Many cases of serious and permanent limb paralysis were reported from the use of non-pneumatic Esmarch tourniquets.^{[7][8][9][10][11][12][13][14]}

In view of reports of serious injuries and limb paralysis with non-pneumatic tourniquets, in 1904, Harvey Cushing created a pneumatic tourniquet. This type of tourniquet compressed the underlying blood vessels using a compressed gas source to inflate a cylindrical bladder. This was superior to the Esmarch tourniquet in two ways: (1) the tourniquet could be applied and removed quickly; and (2) this method of limb occlusion decreased the incidence of nerve paralysis.

August Bier used two tourniquets for administering segmental anesthesia in 1908. In this procedure circulation is isolated in a limb and the limb is then infused intravenously. In 1963 Hamilton E. Holmes reintroduced Bier’s method as a single tourniquet technique. Today, the two-tourniquet technique is used frequently and is called intravenous regional anesthesia (IVRA). It is also commonly referred to as Bier block, or Bier’s method.^[15]

Modern tourniquet system attached to a modern wide contour cuff

In the early 1980s microprocessor-controlled tourniquets were invented by James McEwen,^[16] a biomedical engineer in Vancouver, Canada.^[17] The first US patent for an electronic tourniquet system was awarded to Dr. McEwen in 1984 and to date he has been awarded many more US and foreign patents for tourniquet improvements. Modern tourniquet systems based on Dr. McEwen’s invention have self-checks and self-calibration to ensure that the systems are safe for use. They are also self-contained as they do not require external compressed gas sources to function. They provide accurate control over the cuff pressure through electronic regulators, and have various safety features such as audio-visual alarms for pneumatic leakage and inflation time. The use of automatic tourniquet systems has significantly improved tourniquet safety. Modern automatic tourniquets are self-calibrating and self-contained. These new tourniquet devices also provide a variety of safety features that are not possible in older mechanical tourniquets.^[4][18] As a result of these advances in tourniquet technology, the U.S. Food and Drug Administration classified pneumatic tourniquets as Class I medical devices, indicating that they present minimal harm to the user and do not present a reasonable source of injury through normal use by properly trained clinicians.

In the 2000s, the silicon ring tourniquet, or elastic ring tourniquet, was developed by Dr. Noam Gavriely, a professor of medicine and former emergency physician.^[19][20] The tourniquet consists of an elastic ring made of silicone, stockinet, and pull straps made from ribbon that are used to roll the device onto the limb. The silicone ring tourniquet exsanguinates the blood from the limb while the device is being rolled on, and then occludes the limb once the desired occlusion location is reached.^[21] Unlike the historical mechanical tourniquets, the device reduces the risk of nerve paralysis.^[22][23] The surgical tourniquet version of the device is completely sterile, and provides improved surgical accessibility due to its narrow profile that results in a larger surgical field. It has been found to be a safe alternative method for most orthopedic limb procedures, but it does not completely replace the use of contemporary tourniquet devices.^[24][25] More recently the silicone ring tourniquet has been used in the fields of emergency medicine and vascular procedures.^[20][26] Recently, Feldman et. al. reported 2 cases of pulmonary embolism after silicon ring tourniquet application in patients with traumatic injuries.^[7] The serious and potentially fatal complication was reported involving procedures performed on the lower limb when silicone ring tourniquet was used for exsanguination on the affected limb.^[7]

Recent advances in tourniquet safety have led to the development of personalized pneumatic tourniquet systems. These state-of-the-art modern pneumatic tourniquet systems automatically measure the minimum pressure required to occlude or stop arterial blood flow in a limb (Limb Occlusion Pressure – LOP) and recommend a cuff pressure to be used during surgery that is personalized for each individual patient based on the LOP.^[27] They also have specially designed personalized tourniquet cuffs and matching limb protection sleeves that can conform to the limb shape and size of each individual patient.^[28] The personalization of the tourniquet instrument, cuff and sleeve for each patient further improves safety by allowing lower cuff pressures and lower pressure gradients to be used.^{[2][29][30][31][32]} It is estimated that modern pneumatic tourniquets are used in over one million surgical cases annually.^[33]

After World War II, the US military reduced use of the tourniquet because the time between application and reaching medical attention was so long that the damage from stopped circulation was worse than that from blood loss.
Since the beginning of the 21st century, US authorities have resuscitated its use in both military and non-military situations because treatment delays have been dramatically reduced. The Virginia State Police and police departments in Dallas, Philadelphia and other major cities provide tourniquets and other advanced bandages. In Afghanistan and Iraq, only 2 percent of soldiers with severe bleeding died compared with 7 percent in the Vietnam War, in part because of the combination of tourniquets and rapid access to doctors.^{[citation needed]} Between 2005 and 2011, tourniquets saved 2,000 American lives from the wars in Iraq and Afghanistan.^[34] In civilian use, emerging practices include transporting tourniquetted patients even before emergency responders arrive and including tourniquets with defibrillators for emergency use.

Tourniquet complications[edit]

It is reliably estimated that pneumatic tourniquets are used in more than one million surgical procedures annually in North America. The potential for injury is significant, although the use of lower, personalized tourniquet pressure levels and shorter tourniquet times are reducing the number, nature and extent of reported injuries. Injuries resulting from pneumatic tourniquet use are most commonly pressure-related, resulting either from the use of an excessively high tourniquet pressure level or from the use of an insufficiently low tourniquet pressure level. Ischemic injuries can also result from prolonged tourniquet time periods. The majority of such injuries may be transient, and perhaps not noticed clinically, but some injuries are permanent, or reversible only over extended time periods with prolonged disability being experienced by the afflicted patient.

Complications and injuries related to the use of a surgical tourniquet include: nerve injury, post-tourniquet syndrome, intraoperative bleeding, compartment pressure syndrome, pressure sores and chemical burns, digital necrosis, toxic reactions, thrombosis and other complications such as tourniquet pain, thermal damage to tissues, hyperthermia, Rhabdomyolysis and metabolic changes.^[35] Risk of complications and injuries can be minimized by taking all reasonable preventative measures when using surgical tourniquets.^[36]

Types[edit]

There are three types of tourniquets: surgical tourniquets, emergency tourniquets, and rehabilitation tourniquets. Surgical tourniquets are frequently used in orthopedic surgery while emergency tourniquets are limited to emergency situations to control blood loss. Rehabilitation tourniquets are used to restrict arterial blood flow at a consistent and safe pressure for short periods of time during low intensity exercise to more rapidly increase muscle size and strength.

Surgical tourniquets[edit]

A surgical pneumatic tourniquet with a limb protection sleeve in preparation for surgery

Surgical tourniquets prevent blood flow to a limb and enable surgeons to work in a bloodless operative field. This allows surgical procedures to be performed with improved precision, safety and speed. Tourniquets are widely used in orthopedic and plastic surgery, as well as in intravenous regional anesthesia (Bier block anesthesia) where they serve the additional function of preventing local anesthetic in the limb from entering general circulations.

Modern pneumatic tourniquet systems consist of a pneumatic tourniquet instrument, tourniquet cuffs, pneumatic tubing, and limb protection sleeves.

Instrument[edit]

The purpose of a tourniquet instrument is to safely and accurately supply and regulate the pressure in a tourniquet cuff.

Personalized tourniquet instruments are state-of-the-art, modern pneumatic tourniquet instruments. They include automatic means of estimating the Limb Occlusion Pressure (LOP) of each patient, permitting an individualized setting of safer and lower tourniquet pressures.^[37] LOP can be defined as the minimum pressure required, at a specific time in a specific tourniquet cuff applied to a specific patient’s limb at a specific location, to stop the flow of arterial blood into the limb distal to the cuff. LOP is therefore personalized to each individual patient and each individual surgical procedure. Setting the tourniquet pressure on the basis of LOP minimizes the pressure and related pressure gradients applied by a cuff to an underlying limb, which helps to minimize the risk of tourniquet-related injuries.

Personalized tourniquet instruments have an intuitive user interface; accurate and automatic pressure control for one or more pneumatic channels; audiovisual alarms; and numerous features to improve usability, reduce errors and ultimately increase patient safety. To facilitate LOP measurement and adaptation of tourniquet operation during surgery, some personalized tourniquet instruments include provision for connection of the tourniquet instrument to physiologic monitors.^[38][39] Personalized tourniquet instruments are also becoming more integrated with a wide range of pneumatic cuffs that are connectable to them, to optimize the performance of the overall system for greatest safety, accuracy and reliability.^[40][41][42]

User interface[edit]

Personalized tourniquet instruments have digital displays and easy-to-use user interfaces. Typically, the tourniquet instrument allows the perioperative staff to set the tourniquet pressure, inflate or deflate the tourniquet cuff, and adjust safety settings such as the maximum allowed pressure and time limits. The digital display and control buttons give the surgical staff a straightforward method of monitoring the tourniquet pressure and time, and for changing the various tourniquet settings. Personalized tourniquet instruments have non-volatile memory to enable surgical staff to store specialized settings most appropriate for certain surgeries (e.g. pediatric and hand surgery), relevant data about significant surgical events related to tourniquet usage, and to enable a data printout or transfer to an operating room information network. In addition, personalized tourniquet instruments use intuitive audio-visual alarms to alert the surgical staff of events related to patient safety.

Pressure control[edit]

The tourniquet cuff bladder requires a source of compressed gas to supply a carefully controlled amount of tourniquet pressure. The gas used may be ambient air, nitrogen, or some other gas. Most modern tourniquet systems utilize low-pressure gas provided by pumps, while a few systems use high-pressure gas sources. Note that nitrousoxygen should never be used to inflate the tourniquet cuff, because of the increased risk of fire.

Personalized tourniquet systems utilize an internal electrical pump to compress ambient air to a low pressure; these systems do not require external high-pressure sources, such as portable canisters, portable tanks, or built-in hospital systems.

The pressure regulator adjusts and controls the gas pressure in the cuff bladder. Older, non-computerized tourniquet systems utilize valves that attempt to respond mechanically to changes in pressure. For example, if pressure in the cuff bladder falls, a valve may open to allow more gas to enter the regulator from the gas source; if pressure exceeds a certain level, the pressure may force a release valve to open and expel gas into the environment. Sometimes, the pressure levels at which these two valves turn on and off are quite different and cuff pressure may fluctuate within a certain range above and below the selected pressure. Due to the sensitive mechanical components of these systems, it is very important to follow the manufacturer’s instructions regarding frequent testing, and calibration and to perform these checks before each surgical procedure as recommended. In general, tourniquet systems with mechanical regulators are now considered to be inaccurate, unreliable, and are not suitable for incorporation with modern tourniquet safety features.

In personalized tourniquet instruments, the internal electrical pump, pressure display, and pressure regulator are combined in a single instrument in which a microprocessor continuously monitors and compensates for changing levels of pressure in the cuff bladder. Regulation does not rely on mechanical (pressure) forces to turn valves off and on. Instead, the microprocessor can detect extremely small changes in the cuff pressure and automatically regulate the flow of gas to control the pressure.

Some personalized tourniquet systems use a sophisticated “dual-port” system which gives the most accurate control of cuff pressure and the fastest response to pressure changes. In a dual-port system, each cuff bladder has two ports and is connected to the personalized instrument using two hoses. One port is for monitoring the pressure (“sensing port”); the other port is for inflating and deflating the cuff and for automatically supplying and releasing small amounts of gas during use to control cuff pressure (“supply port”). In some more basic systems, a single port performs both functions for each cuff bladder. Single-port tourniquet systems are less accurate than dual-port tourniquet systems.

Personalized pressures[edit]

Many studies published in the medical literature have shown that higher tourniquet pressures and pressure gradients are associated with higher risks of tourniquet-related injuries.^{[2][43][44][45][46][33][47]} The safest tourniquet pressure is the lowest pressure that will stop the flow of arterial blood past a specific cuff applied to a specific patient for the duration of that patient’s surgery.^[2][48][31] Personalized tourniquet instruments reduce the risk of tourniquet-related injuries by enabling the application of lower tourniquet pressures and pressure gradients to the patient. This is accomplished by the instrument automatically measuring each patient’s Limb Occlusion Pressure (LOP) and recommending a tourniquet pressure based on LOP. LOP can be defined as the minimum pressure required, at a specific time in a selected tourniquet cuff applied to an individual patient’s limb at a desired location, to stop the flow of arterial blood into the limb distal to the cuff.^[40]
The purpose of a tourniquet cuff is to safely stop or restrict arterial blood flow into a portion of an extremity by applying a uniform circumferential pressure around the extremity at a desired location.
Personalized tourniquet cuffs are state-of-the-art tourniquet cuffs that are designed to better match patient limb shape and size, and thus provide more efficient application of cuff pressure to the limb, allowing lower and safer tourniquet pressures to be used.^[49] Personalized cuffs better match patient limb shapes through a variable-contour design that allows the user to adapt the shape of the tourniquet cuff to a wide range of non-cylindrical (i.e. conical) limb shapes. They also better match patient limb sizes through pediatric, adult and bariatric cuff designs.

Tourniquet cuff[edit]

In order to select the correct personalized tourniquet cuff it is important to understand the key properties of a tourniquet cuff. This includes the cuff shape, size, reusability and stabilizer.

Shape[edit]

Tourniquet cuffs can be cylindrical or contour in shape. Cylindrical tourniquet cuffs are designed to fit optimally on cylindrically shaped limbs. However, human limbs may be conically-shaped (i.e. tapered), particularly in extremely muscular or obese individuals. Applying a cylindrical cuff on a tapered limb can result in poor fit, sliding of the cuff distally on the limb during the procedure, and inability to achieve a bloodless field at normal pressures.

Contour cuffs have an arc-shaped design that, when wrapped around a limb, gives them a smaller diameter distally than proximally. Contour cuffs enhance comfort in patients with tapered limbs and reduce the risk of mechanical shearing. It has been reported that contour tourniquet cuffs occlude blood flow at lower inflation pressures than standard rectangular cuffs of equal width, which may be attributable to better cuff fit and more efficient transmission of pressure to deep tissues.^[50] There are two types of contour cuff designs; fixed-contour and variable-contour.

Fixed-contour cuffs are designed to optimally fit one specific limb shape. Applying a fixed-contour cuff on a limb with a different shape will result in a distal gap. Fixed-contour cuffs cannot be adjusted to fit a wide range of limb shapes. Variable-contour cuffs are better for non-cylindrical limb shapes, as explained below.

Variable-contour cuffs are contour cuffs that can be adjusted to the shape of the limb. They have pivoting fastening straps that allow the proximal and distal circumferences to be adjusted, allowing the cuff to conform to a variety of limb shapes, and thus be personalized to each patient. Variable-contour cuffs enhance comfort in patients with tapered limbs, decrease the risk of mechanical shearing, and can occlude blood flow at lower pressures due to the improved fit to the limb.

Size[edit]

Tourniquet cuffs come in a variety of sizes. Different cuff sizes are used on the upper arms, forearms, thighs, and lower legs. Cuff size is also specific to the patient population, with different sizes used for pediatric, adult, and bariatric patients.

It has been shown that a cuff with a wider bladder occludes blood flow at a lower pressure level than a cuff with a narrower bladder.^[50][51][32] This may be related to more efficient pressure transmission to the deeper tissues with a wider cuff. Lower pressures, and associated lower pressure gradients, may reduce the risk of pressure-related injuries to the patient.^[2][48] Furthermore, Estebe et. al demonstrated that a wide tourniquet cuff is less painful than a narrow cuff if inflated at lower pressures and at these lower pressures it is still effective at occluding blood flow.^[31]

Extra care must be taken with unusually small adult patients and pediatric patients to ensure that the correct cuff width is used and that the cuff edges do not lie close to the joints of the limb to reduce the risk of nerve injury.

Reusability[edit]

Reusable and single use tourniquet cuffs are available.

Sterile, disposable cuffs are available for situations that require placement of a sterile tourniquet near the operative site, or for use in contaminated surgical cases.^[35] The design and materials of disposable cuffs are suitable for a single sterilization cycle and single use only and must not be re-sterilized or reused. If a disposable cuff is selected, it must be discarded at the end of the procedure.

Reusable cuffs are not designed to be sterilized and must be used with sufficient sterile draping to isolate the cuff from the sterile field. Reusable cuffs are intended to be used multiple times and cleaned following proper procedures between each use.

Tourniquet Cuff with a Tie Ribbon Stabilizer

Stabilizer[edit]

Tourniquet Cuff with a Releasable Application Handle Stabilizer

The cuff stabilizer is used to assist snug cuff application and to prevent the cuff from shifting during use. Cuff shifting can interfere with the surgical site and may result in loss of arterial occlusion. Generally, tie ribbons are used as the stabilizer, as shown in the top figure to the left. However, some newer cuffs use releasable application handles as the stabilizer, as shown in bottom figure to the left. Releasable application handles allow more consistent cuff application, faster cuff removal, and maintain the cuff in a stable position on the limb during use.

Limb protection[edit]

Wide, contoured arm cuff applied over matching limb protection sleeve

For some cuffs, a matching limb protection sleeve is available to help protect soft tissues under the cuff.^[52][53] Without proper protection, underlying soft tissue is prone to damage caused by wrinkling, pinching or shearing.^[54] Sleeves are sized according to the cuff width and the patient’s limb circumference. They are intended to fit snugly and extend beyond the edge of the cuff to ensure that there is no direct contact between cuff and skin. Sleeve materials that do not shed loose fibers are chosen to avoid lint becoming trapped in the cuff’s hook and loop fasteners, which reduces their effectiveness.

Hazards of non-pneumatic surgical tourniquets[edit]

Caution should be exercised before using non-pneumatic tourniquets in surgical settings. They may apply unknown, uncontrollable and excessively high tourniquet pressures and pressure gradients to the patient’s limb. They do not have the audiovisual safety alarms present in modern pneumatic tourniquets systems, and, recently, Feldman et. al. reported 2 cases of pulmonary embolism after silicon ring tourniquet application in patients with traumatic injuries.^[7] The serious and potentially fatal complication was reported involving procedures performed on the lower limb when the silicone ring tourniquet was used for exsanguination on the affected limb.^[7]

Silicone ring tourniquets, or elastic ring tourniquets, are self-contained mechanical devices that do not require any electricity, wires or tubes. The tourniquet comes in a variety of sizes. To determine the correct product size, the patient's limb circumference at the desired occlusion location should be measured, as well as their blood pressure to determine the best model.^[21] Once the correct model is selected, between two sterile medical personnel will be needed to apply the device. It should be noted, unlike with the pneumatic tourniquet, the silicone ring tourniquet should be applied after the drapes have been placed on the patient. This is due to the device being completely sterile.^[55] The majority of the devices require a two-man operation (with the exception of the extra large model):

1. One person is responsible for holding the patient's limb, the other will place the device on the limb (with the extra-large there are two people needed).


2. Application:
   
   1. Place the elastic ring tourniquet on the hand/foot. Take care to ensure that all the fingers/toes are enclosed within the device.
   
   
   2. The handles of the tourniquet should be positioned medial-lateral on the upper extremity or posterior-anterior on the lower extremity.
   
   
   3. The person applying the device should start rolling the device while the individual responsible for the limb should hold the limb straight and maintain axial traction.
   
   
   4. Once the desired occlusion location is reached, the straps can be cut off or tied just below the ring.
   
   
   5. A window can be cut or the section of stockinet can be completely removed.
   
   
   6. Once the surgery is completed the device is cut off with a supplied cutting card.
   
   

The elastic ring tourniquet follows similar recommendations noted for pneumatic tourniquet use:

1. It should not be used on a patient's limb for more than 120 minutes.


2. The tourniquet should not be placed on the ulnar/peroneal nerve.


3. The silicone ring device cannot be used on patients with blood problems such as DVT, edema, etc.


4. A patient suffering from skin lesions or a malignancy should use this type of tourniquet.^[56]

Emergency tourniquets[edit]

Pneumatic[edit]

Pneumatic tourniquets have been developed for military and emergency use, based on surgical designs proven to be safe and effective over many years. Such pneumatic devices are deployed in Afghanistan and Iraq and in other pre-surgical emergency settings. Pneumatic military tourniquets are more commonly used by medics than by individual soldiers in combat, but both types are designed to be suitable for rapid, one-handed self-application in the field.

Comparatively narrow, non-pneumatic tourniquet straps were developed to be very small in size and light in weight so they could be carried in backpacks by all soldiers, and were developed to be suitable for rapid one-handed self-application by wounded soldiers in combat situations. While effective in helping to stop potentially fatal arterial blood flow in combat, such narrow non-pneumatic tourniquet straps may produce hazardously high, inconsistent and uncontrolled pressures around limbs and may further produce high pressure gradients near the strap edges.

Non-pneumatic[edit]

Mass Casualty Tourniquet[edit]

S.T.A.T. Tourniquet is currently the only tourniquet that has an automatic counting timer and can be applied in 5 seconds by a person with no experience. S.T.A.T. Tourniquet is designed to keep multiple Tourniquet Preloaded on a carabiner for Mass Casualty situations. S.T.A.T. can occlude blood flow on limbs as small as 20mm making it the most ideal tourniquet for pediatric and K9 use.

Silicone Ring Auto-Transfusion Tourniquet[edit]

The silicone ring auto-transfusion tourniquet (SRT/ATT/EED), or Surgical Auto-Transfusion Tourniquet (HemaClear), is a simple to use, self-contained, mechanical tourniquet that consists of a silicone ring, stockinet, and pull straps that results in the limb being exsanguinated and occluded within seconds of application.^[57] The tourniquet can be used for limb procedures in the operating room, or in emergency medicine as a means to stabilize a patient until further treatment can be applied.^[58]

Combat Application Tourniquet[edit]

The Combat Application Tourniquet (C-A-T) was developed by Composite Resources, Inc. and is used by the U.S. and Coalition military to provide soldiers a small and effective tourniquet in field combat situations, and is also in use by NHS ambulance services, and some UK fire and rescue services. The unit utilizes a windlass with a locking mechanism and can be self-applied. The (C-A-T) has been adopted by military and emergency personnel around the world.^[59]

Rehabilitation tourniquets[edit]

Personalized Blood Flow Restriction[edit]

Recently, pneumatic tourniquets have been successfully used for a technique called Personalized Blood Flow Restriction Rehabilitation (PBFRR) to accelerate the rehabilitation of orthopedic patients, injured professional athletes, and wounded soldiers.^[60]

Typically, a person is required to lift loads at or above 65% of their one repetition maximum to have noticeable increase in muscle size and strength.^[61] However, injured patients undergoing rehabilitation may be limited to performing low-load resistance exercise in which strength and size benefits are less evident compared to high-load resistance exercise.^[60]

Patients undergoing PBFRR follow a low-load resistance exercise protocol personalized to their needs while restricting the arterial blood flow in the limb being rehabbed at a personalized restriction pressure based on the patient’s Limb Occlusion Pressure. Arterial blood flow restriction is achieved through the use of a surgical-grade pneumatic tourniquet cuff and surgical-grade tourniquet instrument. A recently published study demonstrated the addition of PBFRR interventions to a postoperative therapy program can induce improvements in strength, muscular hypertrophy, function, and patient-reported measures safely after knee arthroscopy.^[62]