All articles published in the Journal of Special Operations Medicine are protected by United States copyright law
and may not be reproduced, distributed, transmitted, displayed, or otherwise published without the prior written permissionof Breakaway Media, LLC. Contact Editor@JSOMonline.org.

Single versus Double Routing of theBand in the Combat Application Tourniquet
Brandon R. Clumpner, Cadet; Ryan W. Polston, Cadet; John F. Kragh, Jr., MD;
Ted Westmoreland, 18D; H. Theodore Harcke, MD; John A. Jones, BBA, BA;
Michael A. Dubick, PhD; David G. Baer, PhD; Lorne H. Blackbourne, MD

ABSTRACT
Background: Common first aid tourniquets, like the
Combat Application Tourniquet (CAT) of a windlassand band design, can have the band routed through thebuckle in three different ways, and recent evidence in­dicates users may be confused with complex doctrine.
Objective: The purpose of the present study is to mea­
sure the differential performance of the three possible
routings in order to better understand good tourniquet
practice. Methods: A training manikin was used by two
investigators to measure tourniquet effectiveness, time
to stop bleeding, and blood loss. Results: The effective­
ness rate was 99.6% (239/240) overall. Results weresimilar for both single-slit routings (inside vs. outside,p > 0.05). Effectiveness rates (yes-no results for hemor­rhage control expressed as a proportion of iterations)were not statistically different between single and double
routing. However, the time to stop bleeding and blood
loss were statistically different (p < 0.05). Conclusions:
CAT band routing, through the buckle either singly or
doubly, affects two key performance criteria: time tostop bleeding and volume of blood lost. Single routing
proved to be faster, thereby saving more blood. Learn­
ing curves required to optimize user performance varied
over 30-fold depending on which variable was selected(e.g., effectiveness vs. blood loss).
Keywords: hemorrhage; first aid; trauma; damage control;
emergency medical services

Introduction
Tourniquets, in particular the standard issue Combat Ap­
plication Tourniquet (CAT, Composite Resources, Rock
Hill, SC), are currently in the first aid kits of deployedsoldiers.1,2 The CAT has a band that goes around a limb,
passes through a buckle, and, after slack removal, secures
to itself.3-5 This band is then tightened by windlass turns

to stop wound bleeding. The band can be passed throughthe double-slit buckle in three ways — singly througheither one of the two slits or through both slits. Single
and double routings have been advised for one-handed
and two-handed application, respectively.3-5 Recently,
evidence emerged that CATs applied in the field had
patterns of single and double routing at rates that mis­matched doctrinal expectations.1,6-8 Single routing wasused 41% of the time (18% in upper extremity, 23% inlower extremity); all three of these proportions exceeded
expectations of doctrinal use one-handed self-application(about 1% of use) or application by anyone including
other users to upper extremities (about 16%).1,2 Be­
cause 17% was the maximum expectation (1% + 16%),
single routing use of 41% doubled (41%/17%, 2-fold)the expectation.1 Users may be confused by complex in­
structions (multiple pages, multiple slits to choose in thebuckle) or complicated doctrine (one- vs. two-handed ap­
plication, upper vs. lower extremity use, and Care Under
Fire vs. Tactical Field Care).
The present buckle configuration and its routing instruc­tions were based on a field experience of a CAT inventor(co-author T.W.) who related a case of slippage of theband that led to redesign and double routing. However,the cause of that slip was unclear as it slid distal overthe cone-shaped part of the mid-thigh due to aggressive
transport of the casualty away from gunfire. In morethan a decade of war, with thousands of CAT uses, slip­
page of the self-adhering band along the line of pull has
been neither reported nor confirmed. Given this infor­
mation, does it make a difference whether the band issingle-routed or double-routed? Also, single routing of
the band was first compared to answer a minor question
posed from the field: Does it make a difference if single
routing is done through the inside or outside slit? To an­swer the questions, an experiment was designed to mea­
sure the differential performance of the three possible

Note: Study performed at U.S. Army Institute of Surgical Research (USAISR).

34

All articles published in the Journal of Special Operations Medicine are protected by United States copyright law
and may not be reproduced, distributed, transmitted, displayed, or otherwise published without the prior written permissionof Breakaway Media, LLC. Contact Editor@JSOMonline.org.

routings in order to better understand good tourniquet
practice.

Methods
The protocol was approved by the U.S. Army Instituteof Surgical Research Regulatory Office as a laboratory
protocol (Practical Biomedical Engineering Research of
Tourniquet Application and Use, L-12-009). The present
study was executed in May through August 2012. This
study was conducted under a protocol reviewed and ap­
proved by the regulatory office and in accordance withgood clinical practices. Investigators included a pair ofcadets and a tourniquet researcher. The iterations oftourniquet testing were performed by two users: a cadet
who had entry-level tourniquet training and a clinicianscientist who was a tourniquet expert. Both users wereoriented to correct CAT use and manikin testing.
The HapMed Leg Tourniquet Trainer (CHI Systems, Fort
Washington, PA), a simulated right-thigh body segment(leg number 000F) with an amputation injury just proxi­
mal to the knee, was selected as the testing device. The
medial hip-pelvic area had an embedded computer inter­face that included a cellular telephone-like touchpad. The
software (version 1.9) allowed the leg to stand-alone andbe operated by user input through finger touch on thepad. Scenario 1 was used (the casualty had a small build
and the setting was Tactical Field Care, a setting that re­sembles civilian emergency care). The thigh was laid ona desk in the laboratory and was operated in accordancewith the manufacturer’s instructions. The manikin had no
fluids to simulate blood, but bleeding was represented by
red lights that transilluminated the wound. The numberof lights illuminated represented the intensity of bleeding.
All lights on meant no control of bleeding; no lights on
meant bleeding had stopped. The arterial pulse was notedwhen palpable in the popliteal and femoral artery areas.
The user tightened the tourniquets, CAT Generation 6(e.g., windlass turned) until simulated bleeding stopped.
The system reports the blood loss volume as calculatedusing a linear equation from the arterial capacity andnumber of pulses before hemorrhage control. Tourniquet
devices, users, test iterations, and outcomes were uniquely
identified. The iteration began with a device on the desk­
top and not applied to the thigh and ended when the user
touched the touchpad button. The touchpad readout in­cluded iteration bleeding control or not, the time to stop
bleeding, and blood loss. The measurement of the time
to stop bleeding started when the iteration began andstopped when the manikin sensed that the thigh was los­ing no more blood. Effectiveness was defined as the stop­
page of blood loss and the termination of distal pulse.
The CAT has a band that goes around the limb, passes
through a buckle, and secures with hook-and-loop

fasteners on one side of the band by self-adhering on con­tact in order to hold the removal of all slack. This band isthen tightened by windlass turns to stop wound bleeding.
The band can be passed through the double slit buckle(referred to by the manufacturer as the friction adapter)in three ways. It can be routed singly through either oneof the two slits or through both slits. Single and double
routings are instructed for one-handed and two-handed
application, respectively. The one-handed configuration
allows a casualty to self-apply the CAT if an upper ex­tremity is incapacitated. To facilitate this self-care op­tion, the manufacturer packaged the CAT is packaged
in a single-routed configuration and recommends that
the CAT be carried this way in the field. Double rout­ing is intended primarily to stop the self-adhering bandfrom having its hook-and-loop fasteners slip along theline of pull; i.e., the longitudinal axis of the band. Theband has a surface material called Omni-Tape (a Velcro
brand) of hook-and-loop fasteners woven on a single sideof the band. When the band is folded back onto itself,
the hooks-and-loops face each other and engage on con­tact. This single-component closure offers the benefits ofreduced lint contamination and a softer feel against theskin compared to traditional hook-and-loop fasteners.
The number of turns was recorded. One windlass turn
was a 180º excursion arc, the limit of wrist supination inturning of the windlass. The user, by convention, re-grips
the windlass after each 180º arc; so 180º is considered
one turn.
An assessment was also conducted of how easy it is tomake the device ineffective (a surrogate of device slip­
page or malfunction; e.g., the self-adhering band ispeeled back or the CAT is knocked off in casualty trans­port). To test the required contact area of the self-ad­
hering band, a CAT was secured around the manikin as
described above. The self-adhering band was placed di­
rectly on top of itself, with no folds or overlaps to ensurethat the entire width of the band was in contact.
A ruler was placed alongside the band to measure selfadhering band contact with itself, with the zero measure­ment beginning at the outside end of the buckle (Figure1). The self-adhering band was then slowly peeled backoff itself until the self-adhering band slipped. Slippage
was defined as visible loosening of the self-adhering
band. The length of the contact area was recorded in mil­limeters. Iterations ended when the tourniquet loosened(e.g., the band lost its tension when it slipped throughthe buckle).
The centerpiece of the present study was a comparisonof single versus double routing for differential time tostop bleeding and blood loss volume. Because there are
two slits in the buckle, the comparison for single routing
by each of its two options was made. One slit is the near

Single versus Double Routing of the Band in the Combat Application Tourniquet

35

All articles published in the Journal of Special Operations Medicine are protected by United States copyright law
and may not be reproduced, distributed, transmitted, displayed, or otherwise published without the prior written permissionof Breakaway Media, LLC. Contact Editor@JSOMonline.org.

Figure 1 Procedure for Measuring Contact Area

Figure 2 Inside vs. Outside Slit in CAT Buckle

Note: Photograph showing
an arm tourniquet being
measured for distance. The
ruler was placed alongside
the Combat Application
Tourniquet’s self-adhering
band (black strap) to measure
the distance of surface area
contact between the two facesof the band’s hook-and-loop
fasteners.

slit (also called the inside opening or slit) because it isnearer the working end of the tourniquet, with its stabi­lization plate and windlass, whereas the outside (or far)slit is farther away (Figure 2). The double routing trials
had the band go through both the inside and the outsideslit in that order.

Note: Photograph shows the tourniquet’s buckle inside and outsideslits. The tourniquet’s inner strap is within the outer self-adhering bandand has creases as it passes through the windlass and then dives intoand out of the stabilization plate’s two slits before reentering the selfadhering band.

Table 1 Results of Single Band Routing Through the Insideor Outside Buckle Slit

Statistical analysis included use of descriptive statistics(means, medians, standard deviation, minimum, maxi­
mum, percentiles), χ2 test for comparison of turn number
data, and Wilcoxon’s two-sample test for comparison ofmeans among continuous data. Significance level was set
at p = 0.05.

Time toBlood Contact
Single Routing
Stop Bleeding Loss
Lengthby SlitParameters
(sec)
(mL)
(mm)

Near slit

Mean
± SD
MedianMinimum
Maximum
(N)

19
± 6.2
17
11
39
(80)

93
± 19.3
91
33
162
(80)

25
± 5.2
26
18
33
(10)

Outside slit

Mean
± SD
MedianMinimum
Maximum
(N)

19
± 6.6
19
11
39
(80)

92
± 25.7
86
46
161
(80)

27
± 7.2
25.5
18
41
(10)

0.99990.7812 0.4861

Results
Effectiveness rates were 99.6% (239/240) overall for bothusers pooled in that these iterations had hemorrhage con­trolled. Each individual user’s effectiveness rate was notstatistically different from the other’s rate.
Single routing of the band was first compared to deter­mine whether it makes a difference if single routing isdone through the inside or the outside slit. Eighty singlerouted iterations in both options, inside and outside,
were completed: 159 of 160 iterations were effective.
Additionally, all measured performance parameters were
not statistically different. Performance included time tostop bleeding, blood loss, and band contact length (Table
1, p < 0.05). Because the two results were similar and theinside and outside routings were both single routings,
the two data sets (inside and outside single routing) werepooled for the next comparison: single routing versus
double routing.
Effectiveness rates (i.e., yes-no results for hemorrhage
control expressed as a proportion of iterations) were notstatistically different between single and double rout­ing. However, the time to stop bleeding, blood loss, and36

Comparison ofmeans, p value

Note: N is number, sec is seconds, mL is milliliters, and mm is
millimeters.

required contact length were statistically different (Table
2; all p values < 0.05; Figure 3). Time to stop bleeding
increased from a mean of 19 seconds with single routing
to a mean of 26 seconds with double routing. This was
associated with an increase in blood loss from a mean of
93mL to 144mL. Band contact was not a factor in any
double-routed iteration because no slippage occurred
even when there was no hook-and-loop fastener contact.
Additionally, each user exhibited a clear learning curvefor time to stop bleeding and blood loss (Figures 4 and 5).
Much learning was evidenced as a change in performance

Journal of Special Operations Medicine Volume 13, Edition 1/Spring 2013

All articles published in the Journal of Special Operations Medicine are protected by United States copyright law
and may not be reproduced, distributed, transmitted, displayed, or otherwise published without the prior written permissionof Breakaway Media, LLC. Contact Editor@JSOMonline.org.

Table 2 Tourniquet Data by Whether Band Routing Was

Single or Double

Routing:Time toSingle Versus
Stop Bleeding
DoubleParameters
(sec)

Blood
Loss
(mL)

Single (inside Mean ± SD
and outside
Medianslit data
Minimumpooled)+Maximum(N)

19 ± 6.4
18
11
39
(160)

Double26 ± 11.0
21.5
13
63
(80)

144 ±
79.7
114.5
49
445
(80)

< 0.0001< 0.0001

Comparisonof means,
p value

Mean ± SD
MedianMinimum
Maximum(N)

Contact
Length(mm)

93 ± 22.7 26 ± 6.2
87.5
26
33
18
162
41
(160)
(20)
0 ± 0*
0*
0*
0*
(10)*

Notes: N is number, sec is seconds, mL is milliliters, and mm is
millimeters.
*When double-routed, the tourniquet did not loosen when the selfadhering band was completely peeled back from itself.
+
Pooled indicates that the two single routing data sets (each set consist­ing of 80 iterations) were combined to create one, joint data set (of 160
iterations) of all single routed tests.

Figure 3 Blood Loss Results in Single vs. Double Routing for

Two Users

curves with flat performance at and after iteration 1. Fortime and blood loss, continuous variables, performance
became constant at or about 35 iterations. Learning
curves by iteration ranged greater than 30-fold.
When comparing the two users for inter-user perfor­
mance differences, there were no statistically significant
differences except that the cadet, not the expert, had bet­
ter performance for time to stop bleeding and blood loss
in the double routing (p < 0.0001 and p = 0.034, respec­tively) and for time to stop bleeding in the single routing(p < 0.0001). The differences in means were 16 seconds,
59 ml, and 8 seconds, respectively.

Discussion
The main finding of the present study is that the Com­bat Application Tourniquet (CAT) band routing, either
through the buckle singly or doubly, affects two key per­formance criteria: time to stop bleeding and volume ofblood lost. It is not unexpected that single routing proved
to be faster, therefore saving more blood. It is relevantthat no differences were noted in the routing through theinside or outside slit; trainers may now elect to consider
either as acceptable in practice or testing. Effectivenessrates were similar for single routing and double routing.
Single routing proved simpler and easier to apply thandouble routing, as indicated by the high variability ofdata points for double routing in comparison to single
routing (Figures 3 and 4). Along with the faster speedof the single routing were fewer mistakes or problems,
when compared to double routing. Double routing was
susceptible to complications because it had more steps inwhich to err; one complication noted by both users was
the ease with which the self-adhering band unintention­
ally stuck to itself at contact, causing delays in applica­tion during double-routing.
Figure 4 Differential Learning Curves for Single vs. Double

Routing for Blood Loss in One User

Notes: Plot shows the blood loss volume by single (1) vs. double (2)band routing. The gray box bottom and top represent the 25th and75th percentiles, respectively. The median is a straight black line acrossa box.

over time in a steep slope of the trend line, and constantperformance, indicating no learning, was represented bya slope of zero (i.e., a flat line). The number of iterations
required to achieve constant performance varied from 1
to 35, depending mainly on the outcome selected (effec­
tiveness, time, and blood loss) and little on the user (twoindividuals). Effectiveness, a yes-no binary variable, wasyes on the first iteration for each user and remained
yes for nearly every iteration thereafter—steep learning

Notes: Learning by changes in behavior during the 40 iterations oftourniquet use for a cadet user is shown. The volume of blood lost is
the outcome of learning, and double routing (white circles and dashedtrendline) had similar learning as single routing (black boxes and blacksolid trendline).

Single versus Double Routing of the Band in the Combat Application Tourniquet37

All articles published in the Journal of Special Operations Medicine are protected by United States copyright law
and may not be reproduced, distributed, transmitted, displayed, or otherwise published without the prior written permissionof Breakaway Media, LLC. Contact Editor@JSOMonline.org.

Figure 5 Differential Learning Curves for Single vs. Double

Routing for Blood Loss in One User

Table 3 Windlass TurnNumber Results by Single vs.

Double Routing

Windlass Turn Number

Type of
Routing

1

2

3

4

5

Total

Single

22

39

18

1

0

80

Double

0

33

5

0

2

40

Total

22

72

23

1

2

120

Table 4 Clinical Use Pearls and Pitfalls of Single vs.
Double Routing

Single Routing

Double Routing

Pearls
Notes: Learning for an expert user. Double routing had more learning
than single routing until the final iterations where performance became
similar The data collection order for this user was the double before
single routing; so order of learning may have affected results.

Users generally assumed that the single routing can comeundone more easily than double routing (Table 4). We
found this to be true, but our results were surprising.
The minimum length of 41 mm (1.6 in.) was required tokeep the tourniquet secure (Table 2). The self-adhering
band is a 35mm (1.4 in.) wide; therefore, the minimum
contact area was found to be 1435mm2 (2.2 in2). This
area represents the minimum acceptable contact area re­quired to keep the tourniquet secure during laboratory
testing. No folds were present in the band, no mud waspresent, and no clothing or other obstructions were in
the way. This area is much smaller than expected. The
hook-and-loop fasteners, when self-engaged, resist loads
applied along the line of pull. The mechanism throughwhich the self-adhering band is loosened is perpendicu­
lar force; akin to peeling the band back off from itself.
Because of the engagement of the hook-and-loop fasten­ers, the CAT in this leg simulation model is able to apply
the required pressure to stop arterial blood flow withminimal contact area.
The experimental evidence indicates a performanceadvantage for single routing, initially unexpected, that
may have field advantages; e.g., users and casualties may
spend less time in Care Under Fire applying tourniquets
during what may be called an unforgiving minute. Gun­fire rates of dozens of rounds fired from one weapon per
minute are common in war and occasional in civilian
settings such as the violent incidents at Virginia Tech andAurora, Colorado. The above information that indicates
improved performance may prompt discussion among
instructors and policy developers on the use of single-slit
routing for initial application of all CATs. This also has
design implications, specifically for a possible redesignof the buckle to include only one slit, thereby simplifyinguse (Table 3).

38• Hooks-and-loops and buckle• This routing is storage
secure band
configuration• Slack removal is easier• Fastening band is easierand faster• Windlass turning begins
sooner• Placing tourniquet on
limb is easier• Self-application takes
less time• One-handed use is easierand faster
Pitfalls• Users confuse which of • Storage after use requires
reconfiguration
two slits to use• May lose tension before • Slack removal requires buckle
manipulation
band secured• Band may stick to itself• Band secured only by
inadvertently
hooks-and-loops• Fastening band requires added
slit routing• Windlass turning begins later• Added slit routing loses
tension giving slack• Added slit routing adds toapplication time
• One-handed use is harder andslower• Added slit adds second slack
removal step
• More steps risk more errors

A minor finding of the present study is the learning curve
required to optimize performance of the task. Perfor­
mance can be considered stabilized for a user by a slope
near zero on a chart of performance parameter versus
iteration. The learning curve stabilized at or about 35
iterations for both users (Figures 4 and 5). Prior to theexperiment, performance was thought to stabilize ataround four iterations since tourniquets were thought
simple, and previous research evidenced performance
up to four iterations.4 Tourniquet use is simpler than

Journal of Special Operations Medicine Volume 13, Edition 1/Spring 2013

All articles published in the Journal of Special Operations Medicine are protected by United States copyright law
and may not be reproduced, distributed, transmitted, displayed, or otherwise published without the prior written permissionof Breakaway Media, LLC. Contact Editor@JSOMonline.org.

surgery where learning curves stabilize at around 65
iterations. However, the task was not so simple, and thelearning curve was not as steep as projected. One otherobservation noted was that the learning process of rout­ing the band through the buckle was similar for both
single routing and double routing. Routing the bandthrough one slit was able to help the user learn to routethe band through two slits and vice versa. One user who
completed all 40 iterations of double routing first, fol­
lowed by 80 iterations of single routing, showed thislearning transference clearly. When plotting the user’s
performance, the learning curve for double routing flat­
tened out near 35 iterations (Figures 4 and 5). However,the learning curve for single routing was almost flat, as
performance was constant for all iterations. This steady
performance came after the user’s familiarity with therouting and the practice derived from the prior double
routing iterations.
Another minor finding associated with the experiment
was the advent of hybrid intervention: the combinationof a manual maneuver with the use of a device in orderto stop blood flow (Figures 4 and 5). The use of hybridintervention slowed the application of the tourniquet
but decreased the amount of blood lost by the casualty.
User 1, an orthopedic surgeon familiar with the anatom­
ical location of the popliteal artery and the superficial
femoral artery, was able to apply hand pressure throughthe applied tourniquet targeting an underlying artery
before buckle routing. This user’s technique slowed over­
all application but reduced the total amount of blood
lost by slowing the blood loss earlier before even buckle
routing. Additionally, this user’s method relied on the
self-adhering band for the initial pressure by assertive
removal of all possible slack and used the windlass only
for the final stoppage of bleeding. User 2, unfamiliar
with the location of the artery, spent less time manuallytightening the self-adhering band and relied on the wind­lass to apply the required pressure on the limb. Hybridintervention resulted in a slower time to stop bleeding
but a lesser volume of blood lost. The two users’ dispa­
rate results may stem from disparate approaches to theexperiment. One aimed at speed to minimize bleedingtime by replicating rhythmic iterations consistently lis­tening to music, whereas the other aimed to minimize
blood loss by trying novel techniques and allowing morevariation as to maximize new knowledge generation
among iterations. Both strategies had merit in the gamelike experiment.
The findings stated above invite a discussion of decisionmaking and available options. As the CAT is manu­
factured currently, empirically there are three routing
options. A soldier can route the band through the inside
slit, the outside slit, or both slits. As Hick’s Law states,

the time required to make a decision increases logarith­
mically in relation to the number of options available.8
This increase in reaction time equates to time on thebattlefield where the individual applying the tourniquet
is often in danger. Though taught not to use the outsideslit for single routing (by any legitimate doctrine), users
are to use only the inside slit for self-application; the sol­dier must decide these options.3-5 Recently, of 23 singlerouted CATs, 16 were near and 7 outside (30%, 7/23)
indicating a problem, perhaps user confusion.1 Nondoc­
trinal use may indicate that users are confused by thetraining or doctrine. Confusion sources include instruc­tions which have shown outside slit single routing—the
opposite of what is supposed to be taught today.3-5,9Actually, when one looks at the versions of written orvideo instructions by the military services, academicians,
and corporations, these points of confusion are often
unspecified, outdated, unclear, or mixed.3-5 Further com­plicating the options of the user is that single routing istaught for upper extremity use whether self-aid or buddy
aid, but lower extremity use is double-routed whether
self-aid or buddy aid. There appears to be no specific in­struction for self-aid, one-handed to the lower extremity,
perhaps because it is similar to self-aid to the upper ex­tremity (however, it is difficult and slow to double-route
one-handed). Additionally, not only is user reaction timeslower with more options, but decision making abili­ties are also diminished. Compounding these problems
in decision making, education research has shown that
subjects tend toward “choosing the disadvantageous
options more frequently” when placed under stress ingames with established rules.10 Such research is appli­
cable to CAT use, as each CAT comes with packaged
instructions, and tourniquet training is structured. When
individuals place a tourniquet in a stressful situation,
they appear more likely to select the wrong routing op­tion than during training. This educational theory andits supportive data are confirmed by the evidence re­ported from the field.3 The expected maximum rate ofsingle-routed CATs was 17% (1% self-applied and 16%
applied to the upper extremity); but when measuredin actuality, 41% of tourniquets were single-routed, a2-fold increase of real-world data vs. doctrinal compli­
ance.1 Last, during stressful conditions, individuals areless likely to adjust their course of action.11 Less ad­justment could partly explain the two-fold increase insingle-routed tourniquets. An individual may have no­ticed the mistake but was under duress and did not takethe time to correct the mistake. The 2-fold increase indi­cates either a flaw with doctrine, training, or a tendency
to select the fastest option when under stress. Since the
CAT has three different routing possibilities, the user
should be able to explain when each routing option isindicated. Additionally, users ideally must be able to se­lect the correct option under stress.

Single versus Double Routing of the Band in the Combat Application Tourniquet

39

All articles published in the Journal of Special Operations Medicine are protected by United States copyright law
and may not be reproduced, distributed, transmitted, displayed, or otherwise published without the prior written permissionof Breakaway Media, LLC. Contact Editor@JSOMonline.org.

There are several limitations to the present study. The
experimental design did not include actual human bodyparts or blood but rather surrogates. Additionally, theexperiment was conducted in a well-lighted laboratory,
without dirt, without casualty movement, without noise,
and without clothing on the limb. The scenario selectedon the HapMed™ Leg Tourniquet Trainer modeled thecasualty as a small-build individual who needed only
one tourniquet; the manikin findings from three investi­
gators have obvious limitations and it remains unknown
if the findings apply well to real world care. The investi­
gators (two cadets with only prior entry-level tourniquet
training and a tourniquet researcher [clinician–scientist])
do not mirror the user population. Also, the tourniquet
was pre-placed on the desktop, not in its wrapping in thefirst-aid kit of the casualty. Furthermore, the parameterof time to stop bleeding does not take into account any
work done after blood flow stops. This could exclude
extra turns, securing the windlass, writing the time, orassessing the casualty. All events excluded required extra
time and thus leave the subject vulnerable in combat.
Last, the experiment did not include stress. Stress would
likely impair the user’s motor function, which would
highlight difficult steps in CAT application.12,13 The
inverted-U hypothesis states that performance increases
with stress up until a certain point, where performance
begins to decrease. This inverted-U relationship also ap­
plies to motor function.14 The increased stress of combat
could be enough to maximize performance or, as is more
likely, may prove too stressful and may decrease motor
function. Because double routing is a more tedious task
than single, it is expected that added stress will empha­
size the differences between single and double routing.
To design a tourniquet to be perfect in all situations, itwill be complex and complicated; if one empirically deemphasized the worst-case scenario for its rarity to favor
the common, then one may cut the Gordian knot. If thebuckle is remade to one slit only, then training and doc­trine are simplified as to routing; and training is harmo­
nized across the board to one routing for all situations.
This option is open for future research.
Several improvements can be incorporated into future
experiments. Real humans (e.g., volunteers or cadavers)
may be used in lieu of a simulator for confirmatory fieldtesting with induced stress. Field testing could assess theimpact of dirt, debris, clothes, smoke, noise, and bloodon tourniquet application. Medic student use of tour­niquets on manikins may be useful. Field assessments
likely would allow deeper and broader understanding of
the topic beyond the present laboratory experiment. By
focusing on a fundamental and common task in care,the present work draws new attention to an important
set of ideas in first aid; further research may advance on
the present work.

40

References
1. Harcke HT, Mazuchowski E, Brunstetter T, Ritter B.
(2012). Feedback to the field #11: application of the
Combat Application Tourniquet (CAT). Armed Forces
Medical Examiner System and Defense Medical Material
Program Office, United States.http://www.medicalsci.com/
files/f2f__11_cat_tq_application_-_afmes-dmmpo_­_09mar12.pdf accessed 16 July 2012.
2. Kragh JF Jr, O’Neill ML, Walters TJ, Dubick MA, Baer
DG, Wade CE, Holcomb JB, Blackbourne LB. (2011). The
Military Emergency Tourniquet Program’s lessons learned
with devices and designs. Military Medicine. 176(10):1144–1152.
3. Instructions for Use, Package insert labeling of the Com­bat Application Tourniquet. (2004). Combat Application
Tourniquets Co., Southern Pines, NC.
4. Instructions for Use, Package insert labeling of the Combat
Application Tourniquet. (2009). Composite Resources,
Inc., Rock Hill, SC.
5. Instructions for Use, Package insert labeling of the Com­bat Application Tourniquet. (2012). Composite Re­
sources, Inc., Rock Hill, SC.
6. Kragh JF, O’Neill ML, Walters TJ, Jones JA, Baer DG,
Gershman LK, Wade CE, Holcomb JB. (2011). Minor
morbidity with emergency tourniquet use to stop bleedingin severe limb trauma: research, history, and reconcilingadvocates and abolitionists. Military Medicine. 176(7):817–823.
7. Kragh JF Jr, Swan KG, Smith DC, Mabry RL, Blackbourne LH. Historical review of emergency tourniquet
use to stop bleeding. American Journal of Surgery. 203(2):242–252.
8. Kragh JF, O’Neill ML, Beebe DF, Fox CJ, Beekley AC,
Cain JS, Parsons DL, Mabry RL, Blackbourne LH. (Win­ter 2011). Survey of the indications for use of emergency
tourniquets. Journal of Special Operations Medicine.
11(1):30–38.
9. Kragh JF Jr, Walters TJ, Baer DG, Fox CJ, Wade CE,
Salinas J, Holcomb JB. (2009). Survival with emergency
tourniquet use to stop bleeding in major limb trauma.
Annals of Surgery. 249(1):1–7.
10. Markowitsch HJ, Brand M, Starcke K, Wolf OT. (2008).
Anticipatory stress influences decision making under
explicit risk conditions. Journal of Behavioral Neurosci­
ence. 122(6):1352–1360.
11. Starcke K, Brand M. (2012). Decision making understress: a selective review. Journal of Neuroscience Biobe­
havior Review. 36:1228–1248.
12. Martens R, Landers DM. (1970). Motor performance
under stress: a test of the inverted-u hypothesis. Journalof Personality and Social Psychology. 16(1):29–37.
13. Kragh JF Jr, Walters TJ, Baer DG, Fox CJ, Wade CE,
Salinas J, Holcomb JB. (2008). Practical use of emer­
gency tourniquets to stop bleeding in major limb trauma.
Journal of Trauma Injury, Infection, and Critical Care.
64(2 Suppl):S38–S49; discussion S49-S50.
14. Usher M, Olami Z, McClelland JL. (2002). Hick’s law
in a stochastic race model with speed-accuracy tradeoff.
Journal of Mathematical Psychology. 46:704–715.

Journal of Special Operations Medicine Volume 13, Edition 1/Spring 2013

All articles published in the Journal of Special Operations Medicine are protected by United States copyright law
and may not be reproduced, distributed, transmitted, displayed, or otherwise published without the prior written permissionof Breakaway Media, LLC. Contact Editor@JSOMonline.org.

Acknowledgments
Otilia Sánchez aided in manuscript preparation. We
thank Michael J. Benson, Ph., PE, LTC, USA, U.S. Mili­tary Academy, for aid in setting up the individual aca­
demic program for the first and second authors. Ralph
W. Sweet, Jr., aided in study approval and acquiring sup­plies. The study was funded through the U.S. Defense
Health Program (proposal 201105, Operational systemmanagement and post-market surveillance of hemor­rhage control devices used in medical care of U.S. servi­
cepersons in the current war). Financial disclosures thatmight relate to this work: Dr. Kragh is an employee ofthe US Government and receives institutional support
where he works, the US Army Institute of Surgical Re­
search. Non-institutional support occasionally comesfrom other governmental agencies such as the Defense
Health Program and the US Army Medical Researchand Materiel Command for specific projects or related
work. He has offered free advice on scientific matters at
no cost to Operative Experience, M2 Inc., Tiger Surgical
LLC, Tactical Medical Solutions LLC, Combat Medical
Systems Inc., Composite Resources Inc., Delfi Medi­
cal Innovations Inc., North American Rescue Products
LLC, H & H Associates Inc., Creative & Effective Tech­
nologies Inc., TEMS Solutions LLC, Blackhawk Prod­
ucts Group, Hemaclear, Tactical Development Group,
Compression Works LLC, Tier-One Quality Solutions,
Kforce Government Solutions, CHI Systems, Tactical
Emergency And Medical Simulations Training (TeamsT),
Athena GTX, Pelagique LLC, Hawaii Product Develop­
ment Inc., RevMedx Inc., SAM Medical Products, Speer
Operational Technologies, and Entrotech Inc. He hasreceived payment (special government employee) for oc­
casional work for the Food and Drug Administration
for device consultation (510k panelist). In 2007 he re­ceived some funds for work for the National Institutesof Health. He has received honoraria for trustee workfor the non-profit Musculoskeletal Transplant Founda­tion. He has worked as a technical representative to the
US Government’s contracting officer in agreements with
Physical Optics Corporation, Resodyn Corporation,
International Heart Institute of Montana Foundation,
Daemen College, Noble Biomaterials, Inc., Wake For­est Institute of Regenerative Medicine, National Tissue
Engineering Center, Pittsburgh Tissue Engineering Initia­
tive, University of Texas Southwestern Medical Center,
Arteriocyte, Inc., and Kelly Space and Technology, Inc.

Brandon R. Clumpner is a Cadet, U.S. Army, U.S. Military
Academy, West Point, NY. He is studying mechanical engineer­ing with an interest in medicine.
Ryan W. Polston is a Cadet, U.S. Army, U.S. Military Acad­emy, West Point, NY. He is studying mechanical engineeringwith an interest in surgery.
John F. Kragh, Jr., COL (Ret), MC, USA; U.S. Army Insti­

tute of Surgical Research (USAISR). John is a full-time first-aid
tourniquet researcher for the U.S.; a Ranger, he now ranges
golf courses.
John F. Kragh, Jr., COL (ret), MC, U.S. Army,
Orthopedic Surgeon, Researcher, U.S. Army
Institute of Surgical Research, Building 3610 (BHT-2),
Room 222-4, Damage Control Resuscitation,
ATTN: MCMR-SRR-R, 3698 Chambers Pass,
Fort Sam Houston, TX, 78234-6315,
john.kragh1@us.army.mil; 210-539-2210;
Assistant Professor of Surgery, USUHS, Bethesda, MD.

Ted Westmoreland, MSG (Ret), U.S. Army. Ted is anexperienced SOF paramedic with deep expertise in R&D of
prehospital care techniques and medical devices.

H. Theodore Harcke, Jr., COL (Ret), MC, U.S. Army;
Armed Forces Medical Examiner System, Dover Air Force
Base, DE. Ted is a physician, Ranger, and retiree recalled insupport of the Dover Port Mortuary since 9/11/01.

John A. Jones, BBA, BA, Biostatistician, U.S. Army In­
stitute of Surgical Research, Fort Sam Houston, TX. John isa biostatistician in military casualty care; he is a fan of all thegreat things the Scots gave the world.
Michael A. Dubick, PhD, Senior Research Pharmacologist
and Task Area Manager, Damage Control Resuscitation, U.S.
Army Institute of Surgical Research, Fort Sam Houston, TX.
Mike Dubick is a senior leader and investigator in combat ca­
sualty care research with 25 years of military service.
David G. Baer, PhD, Director of Research U.S. Army Insti­
tute of Surgical Research, Fort Sam Houston, TX. Dave Baer isa senior leader in military casualty care; he and his wife, Pam
Brown-Baer, have a brown dog, Bear Brown-Baer.
Lorne H. Blackbourne, MD, COL, Commander, U.S.

Army Institute of Surgical Research, Fort Sam Houston, TX.
Lorne is a senior Army surgeon, experienced leader, trauma
researcher, and educator with SOF experience.

Disclaimer
The opinions or assertions contained herein are the pri­vate views of the authors and are not to be construed as
official or as reflecting the views of the Department of
the Army or the Department of Defense.

Single versus Double Routing of the Band in the Combat Application Tourniquet

41

Est. 2000

Spring 2013
Volume 13, Edition 1
ISSN: 1553-9768™
A Peer Reviewed Journal that Brings Together the International
Interests of First-Responders in the SOF Medical and TEMS Community› Return to Duty After Anterior Cruciate Ligament Reconstruction
Dedicated to the› Fibrinogen- and Collagen-Based Wound Treatments
Indomitable Spirit› Dietary Supplement Use Among Macedonian SOF
and Sacrifices of› Emergency Intraosseous Accessthe SOF Medic› Rugged Handheld Device for Real-Time Analysis of Heart Rate
› Single v. Double Routing of the Band in the CAT› Functional Screening for Vestibular and Balance Problems› Removable Intraoral Soft Stabilization Splint for Military PTSD
› Traumatic Visual Loss and a Limitation of Point-of-Care Ocular US› Gunshot Wound to the Distal Phalanx› Diagnosis and Management of Ichthyosis in an Austere Environment

Plus… Two New Series, TCCC and TEMS Updates, and more!