Page 32 - JSOM Winter 2019

to ten (10) or zero (0) to five (5). The intent was to ensure that Time (or speed) of Application – The second critical criteria
results with studies with N >20 were weighted over studies was how quickly the TQ device could be applied by trained
with N <20. As such, the maximum score a tourniquet could individuals. While there has not been a firmly established stan-
receive was fifty (50). It was determined by the senior author dard for the speed of tourniquet applications, it is generally
with consensus from co-authors that only non-pneumatic accepted that a hemorrhaging casualty can bleed out in 3–5
tourniquets with a score of 40 or higher would be considered minutes. While most of the studies held 1 minute (60 seconds)
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for CoTCCC recommendations. As the pneumatic tourniquets as an arbitrary time standard for tourniquet application, they
in the combat setting are only recommended as tourniquet re- did not all delineate the steps of the application procedure that
placements, then speed of application and simplicity were not were to be completed within time constraints. Additionally,
considered with same degree of importance and were not held most published DoD tourniquet application grading criteria
to the same overall score of 40 as the non-pneumatic devices. include 60 seconds as the time standard for application. How-
As such, occlusion, pressure and specifications were the crite- ever, neither the studies nor some of the DoD publications
ria for pneumatic recommendations. clearly differentiate the time required to achieve occlusion
and to complete further application steps such as securing the
Arterial Occlusion – First and foremost, a limb tourniquet must tourniquet or time recording. Furthermore, the studies did not
adequately demonstrate that it can effectively occlude arterial have consistency in defining the start of timing of the proce-
blood flow of an extremity. Evidence would be further scored dure or standardization for tourniquet access for the test.
high and as acceptable with a greater than 90% efficacy of
occlusion on studies including total N >20 applications and For future analysis, the working group determined that the
medium-high and acceptable on studies with 90% efficacy most critical step in stopping hemorrhage, time to occlusion,
including with N <20 applications. Studies with efficacy re- should be differentiated from the additional steps of appli-
sults of 80-89% were scored in the middle and categorized cation. The optimal time to occlusion would be <60 seconds
as concerning and requiring additional scrutiny. Devices with with an additional maximum of 90 seconds more to com-
occlusion results of 70–79% were considered significantly plete the tourniquet application, including securing the device
concerning and scored low. Studies of devices with occlusion and marking the time. Accordingly, devices with application
efficacy <70% were consider unacceptable and scored zero. speeds of <60 seconds to occlusion and <90 seconds comple-
Devices with occlusion efficacy <50% were scored zero and tion in studies with N >20 applications were scored high and
considered disqualified. acceptable; <60 seconds and <90 seconds in studies with N
<20 scored medium and acceptable. Devices with occlusion
Additionally, only studies that determined occlusion efficacy times of 61–90 seconds were scored low and considered con-
using tourniquet application to humans assessed by Doppler cerning and devices with time to occlusion >90 seconds were
ultrasonography or using high-fidelity limb tourniquet sim- scored zero and considered unacceptable.
ulators were included in this review. A Doppler ultrasound
is a noninvasive test that can be used to estimate the blood TABLE 2 Speed of Application Scoring
flow through blood vessels by bouncing high-frequency sound <60 seconds to occlusion time in studies with N>20
waves (ultrasound) off circulating red blood cells. A regular 5 applications considered successful AND <90 seconds
ultrasound uses sound waves to produce images but can’t to completed application time in studies with N>20
show blood flow. The use of non-Doppler ultrasound, pulse applications considered successful.
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oximetry, or palpable pulse were not considered to be defini- <60 seconds to occlusion time but with an N<20 considered
tive determinates of occlusion as they do not definitively assess 4 acceptable AND/OR <90 seconds to completed application
time in studies with N<20 applications considered
blood flow. acceptable.
61 to 90 seconds to occlusion time in studies with N<20
3
TABLE 1 Arterial Occlusion Scoring considered concerning.
61 to 90 seconds to occlusion time in studies with N>20
96–100% occlusion in studies with N>20 applications 2
10 considered concerning.
considered successful.
96–100% occlusion in studies with N<20 applications 1 Not used
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considered successful. 0 Any time to occlusion >90 seconds considered unacceptable.
90–95% occlusion in studies with N>20 applications
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considered successful. Simplicity of Application – The simplicity of application was
90–95% occlusion in studies with N<20 applications determined as a combination of how easily the device can be
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considered successful. applied, how many steps are required for application and/
80–89% occlusion in studies with N>20 applications or the number of twists, turns, clicks or pumps necessary to
6 10
considered concerning. achieve occlusion. While most tourniquets in this review
80–89% occlusion in studies with N<20 applications could likely gain arterial occlusion, there is the valid and im-
5
considered concerning. portant question of reproducibility in the larger population,
70–79% occlusion in studies with N>20 applications which is why simplicity is an important criterion. In many as-
4
considered concerning. pects, training is the answer to the simplicity or difficulty of
70–79% occlusion in studies with N<20 applications applying a tourniquet. However, it must be recognized that
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considered concerning. the complexity of the steps to apply, the retention of steps, or
50–69% occlusion in studies with N>20 applications particularities increase the overall difficulty.
2
considered unacceptable.
50–69% occlusion in studies with N<20 applications For this review, simplicity of application is defined as correctly
1
considered unacceptable. applying the device after minimal training in a stressful com-
0 Any occlusion rates <50% considered unacceptable. bat setting of low–to–no light, high noise/distraction, extreme
30 | JSOM Volume 19, Edition 4 / Winter 2019