Page 18 - JSOM Spring 2024

15
5
location ). The forearm Ratcheting Medical Tourniquet loca- Dory et al. 2014 for the TPT2 on the SynDaver ®13 and
15
tion in that study was one fourth of the distance from the el- HapMed Trainers correspond with our observations of the
5
bow crease to the wrist crease, so not as distal as was TPT2 pressure-induced, transiently red areas on legs immediately
placement in this study. following TPT2 removal (Table 1). Namely, the TPT2 does
not exert the same pressure across its entire width. 13,15 As
Regarding the arterial occlusion pressure differences between the TPT2 is inflated, it rounds and does not exert pressure
the TPT2 and 3.8cm-wide emergency-use limb tourniquets, the across a full 5.1cm, and of the width that is exerting pres-
limitations of using a small, inflated bladder under only one sure, the highest pressure is exerted at the middle, with much
portion of the 3.8cm-wide tourniquet to provide pressure data less pressure exerted toward the edges. 13,15 Because the TPT2
are unlikely to account for the observed pressure differences. bladder rounds with inflation, differences in limb or device
The thigh and forearm comparison pressures were for Ratch- surface indentation in response to tourniquet pressure appli-
eting Medical Tourniquet pressures that were one ladder tooth cation will affect the width over which the TPT2 is exerting
advance past arterial occlusion and were only for applications pressure.
that maintained arterial occlusion for 60 seconds or longer du-
ration as specified in each study. Therefore, the pressures at The TPT2 was not designed to be an emergency-use limb
4–9
which arterial occlusion occurred with the 3.8cm-wide Ratch- tourniquet but rather as a pneumatic tourniquet that might
eting Medical Tourniquets were even lower than the pressures be considered for use in an out-of-hospital situation such as a
presented for comparison with those of the TPT2 in this study. field aid station replacement of an initial emergency-use limb
tourniquet with an alternate tourniquet. Considering the 13
Regarding non-pneumatic emergency-use limb tourniquets of thighs without occlusion and the high pressures required for
the same width as the deflated TPT2, thigh arterial occlusion the successful thigh occlusions, this study indicates the TPT2 is
was achieved in each of 360 applications with the 5.1cm-wide a suboptimal choice of tourniquet for such use.
OMNA Marine emergency-use limb tourniquet (OMNA,
www.omnainc.com). Across the 60 subjects in the OMNA It is possible that filling the bladder of the TPT2 via the hand
11
Marine tourniquet study, the 5th to 95th percentile pressures bulb rather than via the stopcock system with the pressure
at which thigh arterial occlusion was achieved were 289– sensor and the 60mL syringe, might have allowed reaching
541mmHg with a median of 348mmHg. The thighs ranged arterial occlusion on the larger thighs without the difficulties
11
in circumference from 42.0–76.0cm, and systolic blood pres- encountered regarding pushing air from the 60mL syringe into
sures ranged from 84–136mmHg. 11 the TPT2 at TPT2 pressures over 700mmHg. However, the
pressures required to reach arterial occlusion on those thighs
Searches of PubMed and Google Scholar only revealed three would still have been unacceptably high. 24
published original research reports involving the TPT2. 19–21
Three additional original research reports involving the Study Limitations
TPT2 exist as Naval Medical Research Unit San Antonio re- In addition to the standard laboratory limitations such as no
19
ports. 13,15,22 Only in the Beaven et al. study was the TPT2 actual bleeding, good lighting, limited distractions, and calm
applied to human subjects. The number of subjects was 12, subjects, the subjects were a convenience sample recruited
and all had mid-thigh arterial occlusion with the TPT2, but from friends; college students, faculty, and staff; and surgical
no limb circumference, blood pressure, or tourniquet pressure residents, medical students, and trauma center staff. Addi-
information was provided. 19 tionally, 100% side-to-side overlap of each inner and outer
strap wrap was closely checked in these applications, and that
In the 2016 report by Dory et al., the TPT2 was applied to the would not be likely in non-laboratory applications.
13
®
clothed proximal thigh of a SynDaver (SynDaver, syndaver.
com) with a pump circulating water through the vasculature. Conclusions
The circumference of the SynDaver thigh was not provided.
The internal tourniquet pressure was not provided. The aver- The TPT2 is likely to be useful for developing emergency-use
age contact pressures for occlusion of the SynDaver thigh with limb tourniquet certification device pressures, but it is not a
three non-pneumatic emergency-use limb tourniquets were all desirable tourniquet for any in- or out-of-hospital clinical use.
lower than the occlusive pressures reported for those tourni-
quets on the thighs of live human subjects. 4,6–10 The three other Acknowledgments
tourniquets were the Combat Application Tourniquet (C-A-T The authors thank the following Drake University under-
Resources, LLC, http://combattourniquet.com/), 6,10 Tactical graduates of the Trauma Research Team for their help car-
Ratcheting Medical Tourniquet, 4,6–9 and Special Operations rying out the experiments: Jack Libbesmeier, Justin Akolith,
Forces Tactical Tourniquet-Wide (Tactical Medical Solutions, Abby Minten, Gage Vander Leest, Nia Eberhard-Mattes, Mary
®
www.tacmedsolutions.com). 10 Jonas, Jordyn Carter, Gillian Galinsky, Nick Mishu, McKenna
Nelson, Abishag NiCuai, Tiffani White, Rylee Beardsworth,
The other four reports 15,20–22 involved TPT2 application to Adrianna Clark, Ella Kocina, Adaire MacSwain, and Fiona
HapMed Tourniquet Trainers (CHI Systems, Inc., www. Martin.
hapmedtraining.com), which are not suitable for determining
likely tourniquet effectiveness nor occlusive pressures (see Wall Author Contributions
et al. for a discussion of HapMed unsuitability regarding ar- PW and CB contributed to concept development. PW, CB, DE,
23
terial occlusion effectiveness and arterial occlusion pressure). TR, and CR contributed to project design. All authors con-
tributed to the acquisition, analysis, and interpretation of data
®
The Tekscan I-Scan (Tekscan, Inc., www.tekscan.com) pres- and the drafting or revising of the article. All authors had final
13
sure distribution profiles shown in Dory et al. 2016 and approval of the manuscript.
16 | JSOM Volume 23, Edition 1 / Spring 2024