In the realm of emergency medical response, tourniquets play a critical role in managing major bleeding, especially in extremities. This life-saving intervention, when applied correctly, can significantly reduce the risk of death due to hemorrhage. Tourniquets work by applying pressure to a limb, compressing blood vessels to stop blood flow to a wound. Over time, various types of tourniquets have been developed, each with specific features tailored to different scenarios and user capabilities. This blog post delves into the various types of emergency tourniquets, highlighting their designs, uses, and considerations.
Windlass Tourniquets
One of the most recognized and widely used types is the windlass tourniquet. Models like the Combat Application Tourniquet (C-A-T) fall under this category. The windlass mechanism involves a rod that is twisted to tighten the band around the limb, effectively stopping the blood flow. The C-A-T is favored for its simplicity, reliability, and effectiveness, making it a staple in military, first responder, and civilian emergency kits. Its design allows for rapid application with one hand, making it invaluable in self-application scenarios.
Design
Composition: Windlass tourniquets consist of a band, usually made of a strong, flexible material, which can be tightly wrapped around a limb. Attached to this band is a windlass rod (a rigid rod or bar), which can be twisted to tighten the band further until bleeding stops.
Adjustability: They are designed to be adjustable to fit different limb sizes and apply sufficient pressure to occlude (block) arterial blood flow, ensuring that they can be used on both arms and legs.
Locking Mechanism: Once the desired pressure is achieved, the windlass is locked in place to maintain constant pressure, preventing further blood loss.
Types of Windlass Tourniquets
Combat Application Tourniquet (CAT): Known for its effectiveness and history of use in the U.S. Military, the CAT is a commercial tourniquet that features a strong plastic windlass.
Sam-XT Tourniquet: A more recent addition to windlass-style tourniquets, designed for rapid application with fewer windlass turns required to reach limb occlusion pressure. It features TRUFORCE™ Buckle technology, which locks by itself when a predetermined amount of force is reached​​.
Military Emergency Tourniquet (MET): This is an open-loop system with a sturdy strap and an aluminum windlass. It’s designed for easy fitting around an extremity, allowing for a quick and secure tightening​​.
Special Operations Forces Tactical Tourniquet (SOFTT): Known for its durability and wider band, the SOFTT is designed for use in rugged conditions. It offers comfort and efficiency, making it suitable for various medical scenarios​​.
Operation
Application: The tourniquet is placed around the injured limb, proximal to the injury (between the injury and the heart). It should be as close to the injury as possible without being placed over joints.
Tightening: The windlass is then twisted until the bleeding stops. This action tightens the band, compressing the underlying tissues and vessels.
Securing: The windlass is then secured in place, often with a built-in locking mechanism, to prevent unwinding and loosening.
Applications
Military and Tactical: Originally developed for military use, windlass tourniquets are a critical component of combat medical kits. They are designed for rapid application in high-stress environments.
Emergency Medical Services (EMS): Used by paramedics and first responders to control severe bleeding in pre-hospital settings.
Hospital and Surgical Settings: Occasionally used in controlled medical environments for limb surgeries or when managing traumatic injuries.
Advantages
Effectiveness: Windlass tourniquets are highly effective in stopping life-threatening bleeding from extremities.
Rapid Application: They can be applied quickly, which is crucial in emergency situations where time is of the essence.
Simplicity: Their design allows for ease of use, even by individuals with minimal training.
Considerations and Precautions
Tissue Damage: If applied too tightly or for too long, tourniquets can cause nerve damage, tissue necrosis, and other complications.
Monitoring: Continuous monitoring is necessary to ensure that the tourniquet remains effective and that no additional harm is caused.
Training: Proper training is essential for safe application, as incorrect use can lead to inadequate bleeding control or unnecessary injury.
Ratcheting Tourniquets
Ratcheting tourniquets offer a precise, adjustable method for stopping bleeding. These devices employ a mechanism similar to cargo straps, allowing for incremental tightening. One of the advantages of ratcheting tourniquets is their ability to apply a consistent force, which can be adjusted as needed without complete removal. The Ratcheting Medical Tourniquet (RMT) exemplifies this type, praised for its ease of use and effectiveness in both self-application and use on others.
Design
Composition: Ratcheting tourniquets feature a band made from durable, flexible materials that can wrap tightly around a limb. The key component is a ratcheting mechanism that allows for incremental tightening.
Ratcheting Mechanism: This mechanism consists of a series of teeth that engage with a pawl, allowing the band to be progressively tightened in controlled steps. This design facilitates precise pressure application to occlude blood flow.
Securing and Release: The ratchet allows for easy locking and quick release, providing an efficient means to apply, adjust, and remove the tourniquet as needed.
Types
XFORCE Tourniquet: The XFORCE Tourniquet incorporates a mechanical ratcheting lever, complemented by dual release levers, facilitating tourniquet conversions and reapplication with ease. Unlike the CAT tourniquet, the XFORCE's strap is designed to be self-securing, eliminating the need for the user to manually secure the strap. This feature positions the XFORCE TQ as a highly user-friendly option, significantly simplifying the process for the user. The XFORCE TQ is by far one of the most unique tourniquets on the market today making it the only tourniquet as of 2024 to have dual release levers and a self securing strap designed for tourniquet conversions in mind.
Ratcheting Medical Tourniquet (RMT): This uses a ratchet mechanism for pressure application, offering precise control and ease of use.
Smart Tactical Applicating Tourniquet (S.T.A.T.): The S.T.A.T. tourniquet utilizes a zip tie ratcheting mechanism, enhancing its efficiency and ease of use, especially in high-pressure scenarios. It's uniquely designed to be carried on a carabiner, equipped with 25 or more tourniquets, allowing for rapid deployment in situations requiring quick action. This design makes the S.T.A.T. tourniquet particularly suited for Mass Casualty Incidents (MCIs), where a swift response is crucial, and there may be a limited number of first responders available to manage the situation. Its design and functionality cater to the needs of scenarios where time and efficiency are of the essence.
Operation
Application: The tourniquet is positioned proximal to the wound (closer to the torso than the injury) and is wrapped securely around the limb, avoiding placement over joints.
Tightening: The ratcheting mechanism is engaged to incrementally tighten the band until the bleeding stops. This can be done with one hand, making it accessible for self-application.
Adjustment: If bleeding is not controlled with initial application, the ratchet allows for easy additional tightening without the need to completely reapply the tourniquet.
Applications
Emergency Medical Services: Ratcheting tourniquets are essential in EMS for quickly controlling bleeding in trauma patients.
Military: Their ease of use and reliability under extreme conditions make them standard equipment in military medical kits.
Hospitals and Surgical Settings: Used during surgeries to control blood flow or in emergency departments for traumatic injuries.
Advantages
Precision: The ratcheting mechanism allows for precise control over the amount of pressure applied, reducing the risk of under- or over-tightening.
Ease of Use: Their design makes them easier to apply, especially in stressful situations or when the user has limited strength or dexterity.
Quick Adjustment: The ability to quickly adjust the pressure without removing the tourniquet is critical in dynamic emergency situations.
Considerations and Precautions
Monitoring: Continuous monitoring of the limb is necessary to avoid ischemic damage from prolonged application.
Training: Proper training is crucial to ensure that ratcheting tourniquets are used effectively and safely, minimizing the risk of complications.
Risk of Complications: Although less likely than with other tourniquet types, improper application can still lead to nerve damage, tissue necrosis, and other injuries.
Elastic Tourniquets
Elastic tourniquets, like the SWAT-T (Stretch, Wrap, And Tuck Tourniquet), use a stretchable material that is wrapped tightly around the limb and then tucked in to secure the pressure. This type is versatile, as it can also be used as a pressure bandage for wounds without arterial bleeding. The SWAT-T's simplicity and multi-functionality make it a favorite among civilians for inclusion in emergency and first-aid kits.
Design
Material: Made from stretchable, durable materials, elastic tourniquets can be extended to apply pressure across the limb uniformly. The material's elasticity allows for a wide range of adjustability to accommodate different limb sizes.
Form Factor: Typically, these tourniquets are bands that can be easily wrapped around a limb and secured in place, often with a hook and loop fastener or a buckle system to maintain tension.
Width: They are designed with an optimal width that minimizes the risk of tissue damage while ensuring effective occlusion of blood flow.
Operation
Application: Elastic tourniquets are applied by stretching the band around the limb, proximal to the injury, and securing it tightly enough to stop arterial blood flow but without causing tissue damage.
Adjustment: The pressure can be adjusted by increasing or decreasing the tension of the band before securing it. This adjustment is crucial to achieving the right balance between effective hemorrhage control and minimizing the risk of complications.
Removal: Removal is straightforward, requiring only the release of the securing mechanism, allowing for quick release when blood flow needs to be restored.
Applications
Emergency Medical Services (EMS): Widely used by EMS professionals for rapid control of bleeding in trauma patients.
Hospitals: Employed in both emergency and surgical settings for blood flow management during procedures or after injuries.
First Aid: Common components of first aid kits, given their ease of use, making them suitable for bystanders and first responders in public settings.
Advantages
Ease of Use: Their simple design and the elasticity of the material make them easy to apply, even by individuals with minimal training.
Uniform Pressure Distribution: The elastic material distributes pressure more evenly around the limb, reducing the risk of focal pressure points that can lead to tissue damage.
Versatility: Can be used on a wide range of limb sizes and is easily adjustable to suit individual needs.
Considerations and Precautions
Risk of Over-Tightening: Care must be taken not to apply the tourniquet too tightly, as excessive pressure can cause nerve damage and tissue necrosis.
Monitoring: As with all tourniquets, continuous monitoring of the limb is essential to prevent ischemic damage from prolonged use.
Training: Proper training on the application, adjustment, and removal is necessary to maximize effectiveness and minimize risks.
Considerations for Tourniquet Use
While tourniquets are vital for controlling life-threatening hemorrhages, their application must be done with care to avoid additional harm. Proper training is essential to ensure that tourniquets are used effectively and safely. Users should be familiar with the specific model they carry, as well as general guidelines for tourniquet use, such as the importance of placing the tourniquet proximal to the wound (closer to the torso) but not over a joint, and noting the time of application to inform medical personnel upon their arrival.
The misuse of tourniquets in the Ukraine war has raised significant concerns among medical professionals. Overuse or incorrect use of tourniquets to treat limb injuries can lead to severe complications, including limb loss, physiological complications, and even death. This issue is particularly acute given the often prolonged casualty evacuation times in Ukraine, which frequently exceed six hours. A study highlighted that appropriate tourniquet application occurred in only 24.6% of wounded individuals evaluated in one report. Extended application of tourniquets increases the risk of complications such as compartment syndrome, vascular thrombosis, rhabdomyolysis, and irreversible myonecrosis, which can result in significant tissue loss and necessitate limb amputation.
The importance of proper tourniquet use is emphasized, including early removal if bleeding is controlled to avoid adverse outcomes. Training on tourniquet use that does not fully address the potential for limb loss and other severe complications from prolonged or improper use is considered risky. It's recommended that tourniquets be loosened after one hour if the tactical situation permits, to assess whether major bleeding continues or if other hemostasis methods could be effective. There is a pressing need for improved training in Ukraine to ensure widespread awareness of the risks associated with prolonged or improper tourniquet use. This training is crucial not only for military medical leaders and medics but also for civilian volunteers and trainers from allied countries providing medical training to Ukrainian soldiers. Establishing a trauma registry and tracking through care levels is suggested to enhance performance improvement through timely feedback​​​​ ["] ["]
Conclusion
Tourniquets are a crucial component of emergency response to major bleeding. With various types available, it's important to choose one that suits the potential user's skill level, expected environment, and the scenarios they are most likely to encounter. Regardless of the type, education and practice in the proper application of tourniquets can make a significant difference in emergency situations, potentially saving lives. Whether you're a professional first responder, a member of the armed forces, or a civilian preparedness enthusiast, understanding and having access to a tourniquet is an indispensable part of emergency preparedness.
References
"Misuse of Tourniquets in Ukraine may be Costing More Lives and Limbs than they Save" in Military Medicine, 2024​​. https://pubmed.ncbi.nlm.nih.gov/38242075/