Safety and Efficacy Advances in Surgical Tourniquets

Posted on November 22, 2013. Filed under: Safety and Efficacy Advances | Tags: , , , , , , , , , , , , |

Jim McEwen PhD

 

New AORN Recommended Practices for Surgical Tourniquets

All surgical tourniquet users should be aware that on June 15, 2013 the AORN (Association of periOperative Registered Nurses) published a major update of its recommended practices on pneumatic tourniquet used in surgery.   These guidelines are widely used and followed, especially in accreditation of surgical facilities.  Many changes in recommended practices have been made, and new topics have been added, as outlined below and as given at http://www.tourniquets.org .   The RP is available for purchase at http://aornstandards.org/.

 

Comparative Effectiveness  

Outpatient surgical staff and facilities are paying increased attention to ‘comparative effectiveness’.   Comparative effectiveness research (CER) is a method of comparing different devices and treatments to determine which is the most effective.  The growth of CER highlights the value of research and published evidence quantifying the benefits of medical devices, and a growing body of evidence supports recent advances seen in surgical tourniquet instruments, cuffs and accessories.  Updated information on recent publications and evidence can be found at www.tourniquets.org and in the 2013 AORN Recommended Practices.

Two disturbing developments related to comparative effectiveness have occurred recently.  First, counterfeit tourniquet products have been seen. These counterfeit products have markings and appearances that mimic existing, proven and authentic products, but their quality, performance and safety are suspect or unknown.  Second, cloned tourniquet products have been seen in some countries.  While cloned products do not bear counterfeit markings, the fact that their physical appearance is similar to authentic products may lead users to mistakenly believe that their safety, quality and effectiveness will be equivalent.  This is not the case.  In considering comparative effectiveness, it is critical that surgical facilities and staff verify the origin and authenticity of tourniquet products.

 

Personalized Tourniquet Pressure Settings

It is well established by evidence in the clinical literature that higher tourniquet pressures are associated with higher probabilities of tourniquet-related injuries.  As a result, modern tourniquet systems aim to use the minimum pressure required to stop blood flow in a limb over the duration of a surgical procedure.  A new method based on Limb Occlusion Pressure (LOP) has been shown to allow individualized, optimal tourniquet pressure settings to be achieved.  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.   Some advanced surgical tourniquet systems include means to measure LOP automatically, although LOP can also be measured non-automatically by users.   Further information can be found at http://tourniquets.org/lop.php.

 

Personalized Tourniquet Cuffs

A recent introduction of personalized tourniquet cuffs has also resulted in safer and more effective tourniquet use.  Personalized cuffs are designed to better match patient limb size and shape and thus provide more efficient application of cuff pressure to the limb, allowing lower and safer tourniquet pressures to be used.  The improved fit is a result of the advent of new types of tourniquet cuff designs, in addition to the traditional tourniquet cuff design.  The traditional ‘straight’ tourniquet cuffs are best suited to cylindrical limb shapes.   New types of cuffs are ‘variable contour cuffs’ and allow the user to adapt the shape of the tourniquet cuff to any of a wide range of non-cylindrical (or tapered) limb shapes.  In addition the advent of new cuffs that allow better matching of cuff shapes to individual limb shapes, other advances in tourniquet cuff design have been made for pediatric and bariatric patient populations.  Tourniquet cuffs are now available that are matched specifically to pediatric and bariatric limb sizes and shapes, with comparative effectiveness established in published literature.

 

Reducing Soft Tissue Injuries with Matching Limb Protection Sleeves

High pressures, high pressure gradients and shear forces applied to skin and soft tissues underlying a tourniquet cuff can cause injuries to the skin and soft tissues.  To reduce the nature and extent of these injuries, studies have been published to determine the relative effectiveness of no protective material, underlying padding, underlying stockinette, and underlying limb protection sleeves that are matched to specific limb sizes and cuff sizes.  Study results present evidence that limb protection sleeves improve safety by protecting the skin underlying tourniquet cuffs during tourniquet use, and further provide evidence that greatest safety is achieved through the use of limb protection sleeves consisting of two-layer material specifically matched to the limb size and cuff size.  (See further information at www.tourniquets.org)

 

Reprocessing tourniquet cuffs

Outpatient surgical facilities are increasingly facing the question of whether, when, and how to reprocess tourniquet cuffs.  The answer requires consideration of patient safety, risk management, and cost.

For tourniquet cuffs designated as ‘reusable’ by manufacturers, the answers are straightforward because instructions on cleaning, inspecting and testing cuffs between uses are usually provided by the manufacturers.  Some facilities are reprocessing and reusing tourniquet cuffs designated as being ‘disposable’ or ‘single use’ by the manufacturers.  In such cases, no instructions on cleaning, inspecting and testing cuffs between uses are provided by the manufacturers.  For any facility considering the reprocessing and reuse of disposable or single-use cuffs, the following precautions should be taken.

  • A tourniquet cuff testing program should be established so that each cuff is thoroughly tested according to a written protocol after each use, and prior to the next use, with the results thoroughly documented.
  • A unique identifier should be used for each cuff so that the number of reuse cycles can be recorded.
  • Each cuff should be replaced after a maximum number of reuse cycles has been reached, to reduce the risk of cuff failure and patient injuries during use.
  • A tourniquet cuff testing protocol should be established in accordance with the recommendations of the original manufacturer of the cuff. At a minimum, the cuff testing protocol should include:

(a) a leak test, including inflating the cuff to a maximum pressure recommended by the manufacturer for a period of time, with the cuff wrapped around a test mandrel or laid flat,
(b) a fastener integrity test, to assure that the fasteners are not degraded to the point of being unsafe at the maximum pressure specified by the manufacturer,
(c) a physical inspection of the cuff to detect blockages of the pneumatic passageway in any portion of the inflatable bladder or tubing due to reprocessing damage or fluid entry,
(d) a visual inspection of the cuff to detect damage or deterioration, including: any warping of stiffener due to inappropriate reprocessing; discoloration or contamination of the cuff surface; damage or deterioration of the cuff connector or inflatable portion; and
(e) written documentation and evaluation of the test results before a decision is made regarding cuff reuse.

The complexity and cost of implementing an appropriate tourniquet cuff testing program may mean that the safe reprocessing of single-use tourniquet cuffs may not be cost-effective.

  

Emergency and military tourniquets

Some outstanding work by the US Army’s Institute for Surgical Research has led to the introduction and widespread use of tourniquets in combat settings.  It has been proven convincingly that many lives have been saved that would have been lost without the use of tourniquets.   As a result of these successes in combat settings, the same types of tourniquets are now being used increasingly by police, paramedics and other first responders in non-military settings with similar benefits.    Also, based on the proven safety and efficacy of pneumatic tourniquets in surgical settings over many years, new types of compact pneumatic tourniquets are being developed and used in emergency and military settings.  For example, a recent study of comparative effectiveness led to the introduction and use of pneumatic tourniquets by NATO forces. (See http://www.tourniquets.org for more information.)

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Effectiveness of EMT tourniquet vs CAT tourniquet for limb hemorrhage control

Posted on October 4, 2011. Filed under: Emergency Tourniquets, Military | Tags: , , , |

A recent publication in the September 2011 issue of the Journal of Trauma [1] evaluated the efficacy of two tourniquet systems, the CAT tourniquet and the EMT tourniquet, for controlling prehospital lower limb hemorrhage.   The researchers involved in the study were active serving members of the British Military Medical Services.  Detailed information about the EMT tourniquet is available elsewhere [2].

The recently published study demonstrated that “the CAT tourniquet was ineffective in controlling arterial blood flow when applied at mid-thigh level. The EMT tourniquet was successful in a significantly larger number of participants”. [1]

This published study is the latest in a series that demonstrates the superiority of the EMT tourniquet in controlling prehospital limb hemorrhage.  For example, a study published in 2008 in the Journal of Trauma reported: “the CAT was the second most effective tourniquet at 79%. The most effective was the Emergency Medical Tourniquet (EMT, 92%).”  [3]

As a result of earlier comparative evaluations done by the US Army’s Institute for Surgical Research, the following tourniquet recommendations were made to the US Army:   “Based on these facts it is recommended that the CAT (tourniquets) be issued to each individual soldier, and the EMT pneumatic tourniquet be considered for issue to combat medics. Further, it is recommended that the EMT be issued for all medical evacuation vehicles and echelon I-III medical facilities”. [4]

The full abstract of the latest publication in the Journal of Trauma is given below. [1]
 

Background: Hemorrhage remains the main cause of preventable death on
the modern battlefield. As Improvised Explosive Devices in Afghanistan
become increasingly powerful, more proximal limb injuries occur. Significant
concerns now exist about the ability of the windlass tourniquet to control
distal hemorrhage after mid-thigh application. To evaluate the efficacy of the
Combat Application Tourniquet (CAT) windlass tourniquet in comparison to
the newer Emergency and Military Tourniquet (EMT) pneumatic tourniquet.
 
Methods: Serving soldiers were recruited from a military orthopedic outpatient
clinic. Participants’ demographics, blood pressure, and body mass index
were recorded. Doppler ultrasound was used to identify the popliteal pulses
bilaterally. The CAT was randomly self-applied by the participant at midthigh
level, and the presence or absence of the popliteal pulse on Doppler
was recorded. The process was repeated on the contralateral leg with the
CAT now applied by a trained researcher. Finally, the EMT tourniquet was
applied to the first leg and popliteal pulse change Doppler recorded again.
 
Results: A total of 25 patients were recruited with 1 participant excluded.
The self-applied CAT occluded popliteal flow in only four subjects (16.6%).
The CAT applied by a researcher occluded popliteal flow in two subjects
(8.3%). The EMT prevented all popliteal flow in 18 subjects (75%). This was
a statistically significant difference at p _ 0.001 for CAT versus EMT.
 
Conclusion: This study demonstrates that the CAT tourniquet is ineffective
in controlling arterial blood flow when applied at mid-thigh level. The EMT
was successful in a significantly larger number of participants.
 

References

[1] DM Taylor, GM Vater and PJ Parker. “An Evaluation of Two Tourniquet Systems for the Control of Prehospital Lower Limb Hemorrhage.“  Journal of Trauma – Injury, Infection & Critical Care  71(3):591-595, September 2011.

[2] http://www.delfimedical.com/pts-ii/emt

[3] Kragh JF Jr, Walters TJ, Baer DG, et al. Practical use of emergency tourniquets to stop bleeding in major limb trauma. J Trauma. 2008;64(suppl 2):S38-S50.

[4] US Army Institute for Surgical Research (USAISR).  “Tourniquet Recommendations.” July 2004. (exerpt)

 

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