Page 29 - JSOM Fall 2021

Hypotheses developed included whether times differ by con- may be able to teach them, but surgeons cannot always be
version group or type, whether skill requires essentials such everywhere. The question of who on the ground is to “own”
as practice or experience, and whether time costs to perform TC deserves a doctrinal consideration. Perhaps a provider set,
conversion in caregiving and training develop skills yet tax re- such as flight paramedics, nurses, and emergency physician
sources (Table 3). assistants, may be considered to have their ICTL amended in
the future. The idea of an assistant role in TC is salient (e.g.,
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TABLE 3 Hypotheses Developed to help with extra hands, monitoring, recordkeeping) but re-
Conversion times may differ by group (tourniquet–pressure mains underdeveloped. The ad hoc way that the doctrine of
dressing, tourniquet–tourniquet). TA had been redeveloped, starting in 2001 when the coalition
Conversion times may differ by type (field tourniquet [FT] to went to war, became rather settled over time, at least in the US
pressure dressing, FT1 to FT2). Army, but TC is yet to be doctrinally settled. After paradigms
Clinical conversion skill has essential aspects (knowledge, subtask shift, mop-up work ensues; doctrinal development of TC is
experience, practice). due. While under development, longer-term efforts to form a
Task-step simulation may test tourniquet (improvised, field) common operating framework among systems, regions, and
differences (time, blood loss). nations may be worthwhile to improve interoperability.
Time-costs to perform conversion in care and training may inform
doctrinal development. The time concepts notably revealed caregiving burdens. On
Adult-size devices and conversion tasks may not fit shorter, smaller average, TC time appeared slightly longer and more variable
limbs of children. than that of TAT (1.3-fold [132/105] and 1.1-fold [51.4/46.0],
Anthropometric limb-segment mapping may delimit working room respectively). Because our simulation ignored monitoring of
for tourniquet conversions. TC (e.g., taking blood pressure measurements), the time costs
To remain secure, pressure dressings may need to cover a minimum of TC were biased as too low. IT use took longer than did FT
of uninjured skin. use. IT removal also took longer than did FT removal. Because
TA and removal include steps when the tourniquet compresses
veins closed while arteries are preponderantly open, these are
Discussion
two periods when an intended arterial tourniquet is actually
This preliminary project developed TC concepts and gener- a temporary venous tourniquet. One period is in early tight-
ated hypotheses. The material concepts were based on how ening and the other is later in loosening. This venous tourni-
materials performed. In the first two tests, a TC with a quet effect is unintended but omnipresent in application and
mini-compression dressing was too short for sufficient turns removal, yet users, instructors, or researchers rarely mention
around the limb to reliably secure the dressing to the limb; these facts. Their importance is that longer times in applica-
the number of wrap layers were too few and skin coverage tion and removal are when the core has a net blood loss. As
was minimal, which could have risked slippage. We therefore IT was longer in both tasks, its sum loss is worse. We thought
switched to longer and wider wraps that fit limbs better. In ad- that simulation of IT versus FT by task-step durations might
dition, 6-inch-wide wraps suited larger limb-segments, while estimate the IT–FT mean difference in blood loss (Table 3).
4-inch wraps suited smaller ones. In matching wraps to limbs, Releasing a tourniquet before completing PD seemed inappro-
we felt it was easier to overwrap excess length of material than priately risky for novices yet suited an expert. Tourniquet–PD
to overstretch shorter material. However, larger materials conversion was slower on average compared with tourniquet–
had greater volume, weight, and cost. A Goldilocks strategy TC. Time costs may be researched to inform caregiving and
seeking suitable properties of materials for TC may deserve training choices (Table 3).
consideration for device design, materiel development, testing
of candidate items, customer evaluation, doctrinal selection, The limb findings by platform type were disparate. Compres-
logistics supplying, training enactment, and care implemen- sive indentation varied widely and impacted the tourniquet
tation (Tables 2 and 3). In conversion, passing a tourniquet user’s mechanical actions, altered choices among technique
loop over any applied tourniquets on large limbs may cause it details in task steps, and fostered development of mechanical
to catch on the tourniquets; the loop may require opening or intuition. Some limbs were realistic and useful; others were
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resizing so as not to snag. neither. Previously, indentations of noodle limbs were noted
to be similar to caregiving squeeze indentations. A recent ca-
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TC is a plain procedure in manuals, curricula, articles, and daver study further noted similar effect sizes. Development
reports, but the idea of it as a procedure dissociable from TA of hand-feel and mechanical intuition appear to be relevant
is doctrinally less clear. For example, TA is a common task to training.
for all US Army Soldiers at entry level, but there is not a clear
doctrine as to whom TC training applies (i.e., skill level of Sol- On limbs, tourniquet bands sited but not tightened had loops
dier or military occupational specialties [MOS]). Importantly, displace often and easily in various directions. Further, slipping
we found no individual critical task list (ICTL) by MOS type tourniquets tended to need manual stabilization to minimize
that included TC. The current list of Tactical Combat Casualty displacement before and during tightening, especially on hard,
Care skills by role of caregiver has no note of TC, but it is un- smooth limbs. Previously, an experienced tourniquet user
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der consideration. Some reports indicate that a medical officer noted that novice learners tend not to put their hand over the
or the most senior medical person available should perform or CAT loop and limb, as experienced users do, but inadvertently
supervise TC. Waiting to convert a tourniquet worked fairly grasp the rod and cause extra slack in the inner band. Over the
well for us in Baghdad in 2006, but evacuation times were decades, we have seen such rod grasping more often among
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short, on average. That luxury of speed was absent in other novices using hard, smooth manikins than with other novices
situations, when limbs were lost or shortened. 7,33,36 Limb sur- using realistic, lifelike manikins. Such grips appeared intui-
geons (orthopedic, vascular) perform these interventions and tively to hold the tourniquet still to counteract slippage but left

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