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Windlass Non-Pneumatic Tourniquets – Pros & Cons

Windlass Non-Pneumatic Tourniquets – Pros & Cons

January 04, 2018 0 Comments

Windlass Non-Pneumatic Tourniquets – Pros & Cons

 

As we’ve previously stated before the best tourniquet is the tourniquet that is right for you. If you feel more comfortable with a particular type, or brand of tourniquet, that is the best tourniquet for you, just ensure you periodically review new innovations, and thoroughly test all types of tourniquets. Currently, there are four primary types of tourniquets on the market. Depending on whom you talk to about tourniquets, you will get a wide array of opinions and recommendations. Always consider the source of the information, identify any conflicts of interest, and take the knowledge gained from that interaction and apply whatever percentage works best for you. In addition, take into consideration that it is very possible that social media accounts that look like actual people, may in fact be marketing teams or company representatives posing as external independent people. So do your research. For the purpose of this article we will only discuss the windlass tourniquet type. The other types will be written about in follow-on articles.

 

  1. Windlass
  2. Elastic Band
  3. Pneumatic
  4. Ratcheting

 

Windlass Tourniquets:

can take a few forms, with the most common being a windlass bar. These tourniquets are constructed of a webbing sleeve with or without Velcro and other means of forming and keeping a loop such as buckles or rings. Inside the webbing is an internal webbing strip that is threaded through the center of a windlass bar. When twisted it twists the internal webbing strip to reduce its length, thus producing compression that may occlude blood flow in the limb. The bar once tight enough is then locked in place with a variety of different securing mechanism. They typically cost about $5 to manufacture and are retailed with a 600% mark-up somewhere around $29.99 USD.

            In addition to the bar type of windlass tourniquet, there are also some that employ an internal windlass mechanism that uses a more user-friendly type of windlass that winds a cable to create compression.

 

Pros:

  1. Can Occlude Arterial Blood Flow: Archeologists have found Windlass tourniquets as old as the Roman Empire (753 BCE – 27 BCE). This suggests that this ancient design was popular in the Iron Age (1200 BCE – 586 BCE) and Before the Common Era (BCE) times, more typically known as BC. https://en.wikipedia.org/wiki/List_of_archaeological_periods_(Levant)
  2. Manufacturing Expense: Windlass bar tourniquets are simple and very inexpensive to manufacture. This means they can be made quickly, and for less than $5 USD.
  3. Less Moving Parts: Less moving parts, means less cost to produce, and less chance of something going wrong. Having more moving parts doesn't necessarily mean a lack of effectiveness, as the cliche saying goes, "There is more than one way to skin a cat." High quality design, materials, and extensive testing ensures no matter how complex or simple a device is, it will work.

 

Cons:

  1. Only Locks On One End: To lock the windlass bar in place you must turn the bar 180 degrees to lock it in to its secured position. This means you may exceed the required compression needed for occlusion, and more importantly you cannot make precise adjustments to maintain occlusion pressure, which studies have shown decreases with time with windlass bar mechanisms.
  2. Twisted Webbing: A contributor to the loss of occlusion pressure over time is that the internal webbing strip is twisted. This means that as the webbing reaches its maximum force load it also reaches maximum length, which may allow movement of the twisted webbing, contributing to the loss of occlusion pressure over time.
  3. Unnatural Twisting Application Movement: Once the webbing is secured tightly around the limb in the correct position the user must twist the windlass bar with one-hand. While it is possible to use 1 or 2 hands, the movement can be a bit odd for the unfamiliar and will become increasingly difficult as forces increase.
  4. Tourniquet Width: While windlass bar tourniquets appear to be 1.5" (3.81 cm) wide, they are in-fact only 1" (2.54 cm) wide. This is because the actual functional part of the tourniquet is contained within the 1.5" webbing sleeve, and is only 1" in width. Furthermore, since this 1" (2.54 cm) webbing strip is twisted to shorten and reach occlusion pressure that means that the area closest to the twisting will reduce even further from 1" to as thin as 1/2" (1.27 cm). Limb Occlusion Pressure (LOP) is calculated with the following formula: LOP = (Limb Circumference / Tourniquet Width) * 16.67 + 67                 The Wider A Tourniquet, The More Effective
  5. Windlass Bar Breaks: It has been known for quite some time that the amount of force required to twist a bar has been known to break the windlass bar resulting in a catastrophic failure of the device. When you consider that if your tourniquets are supplied by a government organization it is highly likely that the lowest bidder, who makes their tourniquet with the least expensive materials available, supplied your tourniquet.

Notice the carbon fiber windlass bar deforming and the reduction of the 1" (2.54 cm) webbing width near the windlass above.

 

At the end of the day you may like a Windlass Tourniquet best, and there is nothing wrong with that as long as you are informed about its advantages and disadvantages.