Page 52 - JSOM Fall 2020

cross-sectional shapes and diameters appeared to fit expecta- Future directions of scholarly work are several. How-to in-
tions of local lumens. Later, the research group led by Piper struction in steps of performance may be tailored to fit specific
Wall, a veterinarian-scientist in a surgical education depart- needs like the Ranger way of converting a hasty tourniquet to
ment, developed a set of preclinical studies 25–29 detailing how a deliberate tourniquet. 17,21 SSG Decker had another situation:
under-tourniquet pressures exponentially drop timewise and reperfusion after prolonged ischemia. Decision-makers may
7
require rechecks starting on a schedule akin to Baghdad’s. consider development of a new task trainer for realistic feed-
back in conversion performance. Conversion may be simulated
For troubleshooting recurrent bleeding by making a rewrap, concurrently with its clinical monitoring. An accounting by
the need was deduced to be a pressure threshold to be met so provider skill level could help because some sources of conver-
the manikin could determine that bleeding was controlled. sion information contraindicate amputation 4,34–36 while others
Notably, pressures required to control bleeding are inversely do not 37–39 or deal in a specific setting 4,40–44 but not others.
related to compression width, 25,27,30,31 and the wrapping was
wider than the tourniquet band. The manikin is a tourniquet Conclusions
trainer made to accommodate most designs of tourniquet, such
as windlass tourniquets or pneumatic tourniquets. Wrap tour- In this study, we tested a method of converting use of a limb
niquets are a less common design but can be made to have a tourniquet to its use as a pressure dressing. The investigator
tourniquet effect. 25,27,28,32 The investigator knew ahead of time performed faster in a classic power law of practice as experi-
that wraps could act as tourniquets. He learned in tests to re- ence was accrued. The tourniquet-use results were uniformly
wrap more tightly, attain higher pressures, and achieve more good, whereas conversion results were worse and more var-
reliably tourniquet effects with wrapping. However, he also ied. The procedural method needs further development. A
knew of pain, skin shearing, blisters, and nerve injuries that are conversion-capable manikin might help.
risked with excessive compression. He aimed to bracket pres-
sures high enough yet also low enough—a Goldilocks strategy. Funding
The investigator is experienced, but this skill of estimating the This project was funded by the US Army Medical Research
physical quantity of pressure applied to the skin by the effort and Development Command.
of wrapping is an art he is still learning moderately. The prin-
cipal troubleshooting was in the step of wrapping the elastic Disclaimer
bandage tightly enough for the manikin-measured pressure to The views expressed in this article are those of the authors and
surpass a threshold. That threshold initially was unknown, but do not reflect the official policy or position of the US Army
as tests accrued data and the investigator learned, the bracket- Medical Department, Department of the Army, Department of
ing narrowed toward a threshold near 137mmHg. That thresh- Defense, or the US Government. The authors are employees of
old required high tension in the elastic bandage, much physical the US Government. This work was prepared as part of their of-
effort to wrap successfully, and repeated exertions and longer ficial duties and, as such, there is no copyright to be transferred.
durations in rewrapping while troubleshooting to achieve it.
The hard manikin deformed little when compressed by the Disclosure
wrap because, under the thin silicone skin, the hard plastic The authors have indicated that they have no financial rela-
was incompressible. The tourniquet-wrap difference in thresh- tionships relevant to this article to disclose.
old in caregiving and research is substantial due to the width
effect. 14,25,27 As compression widens, that width effect lowers Author Contributions
thresholds, because wider wraps need less pressure than nar- All authors participated in study conception and design. JFK
rower tourniquets. The manikin incompressibility was unrealis- resourced, managed, and oversaw the study and collected
tic. Also, the tension, effort, and pressure required for a wrap to data. JFK and JKA analyzed data. All authors participated in
control bleeding in the manikin were higher than in actual care. writing the manuscript and approved its final version.

Limitations of the present study are numerous due to its de- References
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(pulse) sites block sites for transducers. Manikins do not clot. York, Little Brown; 2012.
The new knowledge identified here is at a readiness level 2, 4. Drew B, Bird D, Matteucci M, et al. Tourniquet conversion: a rec-
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a step of roll-gauze placement. Also, no pressure transducer hemostasis increases bleeding. A randomized study of 77 knee re-
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50 | JSOM Volume 20, Edition 3 / Fall 2020