Tourniquet use has once again become ubiquitous for controlling massive hemorrhage. Research has shown that prompt and proper use of a tourniquet prior to the onset of shock can help prevent death. Some of the “myths” surrounding tourniquet use, such as “the patient will lose their limb,” or “there will be permanent damage as a result of tourniquet use,” have been disproven or minimized.
There are many different devices that are being marketed and sold as tourniquets, and there are a lot of factors to consider when selecting a device, such as width, durability, size (for easy storage and fitting around an extremity) and safety closures to ensure the tourniquet is prematurely released.
The Facts
Tourniquets are a fast and effective tool to stop major extremity bleeding when used properly. There are some risks associated with tourniquets, mainly from improper use, lack of training or prolonged tourniquet times. Guidelines developed by the Committee for Tactical Emergency Casualty Care (C-TECC) exist to aid in assuring that providers use tourniquets correctly and lessen the chance of complications. These guidelines are based on existing evidence, best practices and military recommendations and experiences. C-TECC takes into account the differences in civilian populations and operating parameters in the guidelines, and doesn’t recommend or endorse a particular device.
Agencies should consult tourniquet studies and their medical directors prior to selecting any device, and not necessarily rely on recommendations or endorsements of devices used by the military. Studies have shown that improvised tourniquets are ineffective in 40% of applications. C-TECC recommends a commercially produced tourniquet as the first choice.
Proper placement of tourniquets depends on the operational situation facing the provider. If in a direct threat environment (hot zone) where there is imminent danger to the provider or patient, the tourniquet should be placed high on the extremity over the clothes.
In an indirect threat environment (warm zone) or during non-high-threat situations, the tourniquet should be placed directly against the skin several inches above the wound, but not over a joint. If the provider can’t easily determine the extent of damage, the tourniquet should be placed high on the extremity.
It’s important for providers to use direct pressure and/or pressure points to help control the bleeding while placing and tightening a tourniquet. A proper tourniquet should result in not only visible control of bleeding, but also the loss of a distal pulse in the extremity. If one tourniquet is not enough to control the bleeding, a second tourniquet should be added next to the first device.
Once a tourniquet is in place, the subsequent goal is to reduce chances of neurovascular damage to the extremity by de-escalating or downgrading the tourniquet. Research shows that there’s a minimal chance of damage, which can be transient or permanent, when using tourniquets. Perfusion intervals, or loosening the tourniquet in 15—20 minute intervals, isn’t recommended and doesn’t reduce the chance of complications. Research also shows the chances of complications increase if a tourniquet is left in place for more than two hours.
MILITARY EMERGENCY TOURNIQUET (MET): GENERATION 1, 2 & 3
Tier-One Quality Solutions
The MET is a lightweight open-loop system composed of a sturdy strap and aluminum windlass. As a true open-loop system, this tourniquet comes apart completely to place around a limb and doesn’t need to be fully cinched down prior to engaging the windlass; even if loosely applied, by turning the windlass the slack will uptake and fully tighten the tourniquet. It has two securing points to lock down the windlass after application: one that is adjustable and one with Velcro. The Generation 1 & 2 models have a narrow strap, while the Generation 3 version (shown below) has a wide strap. This tourniquet is very effective, but requires training for personnel not familiar with manufactured tourniquet operations.
COMBAT APPLICATION TOURNIQUET (CAT): MULTIPLE GENERATIONS
North American Rescue Products
The CAT was one of the first manufactured tourniquets and thus is one of the most common used by the military, and it’s saved countless lives. There are many generations of the CAT. Users should assure they’re utilizing the most current version as it corrects some of the performance issues from earlier generations. The tourniquet strap comes completely apart to place around a limb, but it’s a closed-loop system that has only a limited three-inch uptake. This means users must tightly secure the tourniquet strap to the limb prior to engaging the plastic windlass. Additionally, according to the manufacturer, for proper application the tourniquet strap must be through the plastic buckle differently depending on whether it’s being used on an upper or lower extremity. The strap is secured on itself with Velcro, and there is one locking point for the windlass on this device.
SPECIAL OPERATIONS FORCES TOURNIQUET (SOF-T) AND SOF-T WIDE
Tactical Medical Solutions
The SOF-T is a true open-loop tourniquet with a solid metal windlass. Early versions have a narrow strap and a metal “alligator” clip with a locking screw to secure the strap. There are two plastic D-ring securing points for the windlass once applied. For these tourniquets, users should make sure the locking screw is secure prior to engaging the windlass to avoid unintentional loosening of the tourniquet.
The newer generation, the SOF-T Wide, replaces the narrow strap with a wider version, and the alligator clip and screw was changed to a break-apart buckle. One of the securing points was removed to make room for the new buckle, so this version has one D-ring to lock down the windlass after application.
MECHANICAL ADVANTAGE TOURNIQUET (MAT)
Pyng Medical
This device is constructed of plastic preformed into a “C” shape to be applied around the limb. As such, it comes in two sizes: one for the arm and one for the leg. It’s a closed-loop system where the strap is easily removed for application and simply hooks back on for application. The internal mechanism for tightening the tourniquet is a plastic dial that, when turned, draws up a length of cord inside the tourniquet cuff. As such, it only has limited uptake so the tourniquet strap must be tightly applied prior to engaging the internal mechanism. This tourniquet is easily released by either lifting the plastic hook that locks down the strap, or by pressing the release button on the side of the device.
RATCHETING MEDICAL TOURNIQUET (GENERATION 3)
m2 Inc.
This device is a closed-loop tourniquet that tightens using a ratcheting, self-locking buckle. This generation has a wide strap that can be fully opened to allow for placement around an entrapped limb and is then routed through a metal ring and tightened down prior to engaging the ratcheting buckle. Once pressure is applied, the buckle automatically locks, allowing pressure to be securely maintained. Inside the buckle is a release that allows for simple removal of the device.
EMERGENCY MEDICAL TOURNIQUET (EMT)
Delphi Products
This tourniquet is a pneumatic tourniquet that closely resembles a blood pressure cuff with a more robust securing mechanism. It’s an open-loop system that is easily applied and will compress even if loose on the limb. Unlike a blood pressure cuff, the pneumatic bladder in the EMT is reinforced to prevent loss of air when it’s inflated, allowing pressure to be maintained on the limb once it’s locked down. This device is consistently rated highly in various tourniquet effectiveness studies, but as a whole is more expensive, bulkier, and heavier than most of the windlass type devices.
SWAT-T, TK4, NATO TOURNIQUET AND OTHER “BAND” DEVICES
These devices are simple elastic bands of varying composition and width, some with locking devices and some without. They’re applied by wrapping the device around the limb, then applying compressive pressure by fully stretching the band as it’s wrapped repeatedly around the limb. Unless fully stretched and properly applied, these devices may not provide the necessary force on a limb to completely occlude blood flow. As such, users of these devices should ensure the end-point of tourniquet application has been attained (absent distal pulse), as there is a chance to only cause venous constriction if not made tight enough. Some agencies utilize the SWAT-T as an effective pressure bandage. These elastic band devices may also prove useful on pediatric and other patients with small limbs.
SUMMARY
Tourniquets save lives by rapidly controlling exsanguinating hemorrhage with a good safety profile. There’s extensive research, both empirical and anecdotal, on the many available commercial devices. Prior to purchasing, the user should complete due diligence and review all available data. Each of the commercial tourniquets has both pros and cons. It’s imperative for the user to both understand these strengths and weaknesses and to practice with the chosen device to solidify the psychomotor skill of application to allow for the most efficient use of the device.
RESOURCES
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