Page 121 - JSOM Winter 2023

Tourniquet Trial in Morbidly Obese Adults Digital Patient Simulation for Training Casualty
(TTMOA) Care in Scenarios Involving the Use of Chemical
James Vretis, MD Warfare Agents
ommercial tourniquets have been designed primarily for Dr. rer. nat. Julia Hofmann, Bundeswehr University Munich,
Ccare of combat casualties. More than 5% of American men Institute for Information Technology
and nearly 10% of women are morbidly obese, with a BMI of Background: Practical experiences with the treatment of casual-
2
40kg/m or more. Tourniquet use for control of extremity hemor- ties in scenarios where chemical warfare agents were used, are
rhage in trauma patients is associated with increased survival with rare. Therefore, specialized training for casualty care plays here a
only minimal tourniquet-associated morbidity. Use of tourniquets decisive role. Conducting training as a real-life simulation is time-
on morbidly obese patients should have survival benefits similar and resource-intensive. A digital patient simulation can comple-
to those seen in the general adult population. We hypothesized ment traditional training and provide meaningful support for both
that there would be differences in the efficacy of commercial tour- trainers and trainees, especially in Roles 1 and 2. Usage context:
niquets that had been designed for military personnel when ap- The patient simulation presented here is intended to be used in the
plied to morbidly obese patients. training of chemical, biological, radiological and nuclear defense
(CBRN) specialists in the German Armed Forces. Currently, it is
The study was a prospective and non-blinded test of 12 commer- limited to training patient care in scenarios involving the use of
cial tourniquets on a morbidly obese thigh hemorrhage test model chemical weapons. The digital patient simulation can plausibly
using three sized manikins to simulate morbidly obese thighs. We represent all typical symptoms of the five groups of chemical war-
were unable to find reports of any morbidly obese thigh hemor- fare agents. Additionally, combined combat-related injuries and
rhage manikins. A morbidly obese thigh hemorrhage manikin test chemical weapon trauma are possible. The patient simulation is
model was developed using commercially available 10% ballis- linked to visualizations of the casualties in a professional game en-
tic gelatin to simulate soft tissues with a 0.87-inch dowel rods gine, which allows for a realistic representation of the symptoms
to simulate an adult femur. Metal rods with diameters of 0.25in of a chemical agent trauma. Currently, training for operational
were placed in the mold to create holes on the ballistic gelatin to care is only supported for Role 1. The Patient Simulation: The
simulate common femoral arteries. Manikin diameters of 29, 35 patient simulation is based on the physiology model that was de-
and 41 inches corresponding to measured thigh circumferences in signed for the training of the first responder in the German Armed
a Level III trauma center over a 1-month period were fashioned. Forces. This physiology model for conventional trauma supports
the training of casualty care for combat-related injuries according
Each tourniquet was tested twice on each of the test manikins start- to the TCCC algorithm. The vital signs for combat-related injuries
ing with the largest diameter and progressing to the next smallest, were supplemented by those for chemical agents when expanding
until all manikins had been used. The order of tourniquet testing the physiology model. The principles of action for some groups of
was randomized. A tourniquet was deemed effective if it was able chemical warfare agents were formally described and can thus be
to stop the flow of water from the manikin for 30 seconds and linked to already implemented pathophysiological processes in the
was able to be secured according to manufacturer instructions. If a physiology model. Outlook: The use of this hybrid patient simula-
tourniquet was not long enough to go around a manikin, a second tion (considering both conventional trauma and injuries caused by
tourniquet was attached to one end of the first tourniquet and the chemical weapons) for training in medical CBRN protection will
tourniquets were tested in a series configuration. If a tourniquet be evaluated at the end of the year in conjunction with an CBRN
was long enough to fit around a manikin but did not stop flow course in the German Armed Forces.
of water, a second similar tourniquet was applied next to the first
tourniquet and tightened in a parallel configuration. Can Early Platelet and Leukocyte Activation
Predicting Complications After Major Burn Injury?
The Stretch Wrap And Tuck (SWAT) and Rapid Application Tour-
niquet System (RATS) tourniquets apply compressive forces by the Martin Rozanovic, MD, University of Pécs
elastic recoil action of the tourniquet strap. The Combat Applica- Background: Major burn injuries lead to significant tissue destruc-
tion Tourniquet (CAT), Sam XT (SAMXT), Tactical Mechanical tion, which can result in increased platelet function and a height-
Tourniquet (TMT), SOF Tactical Tourniquet – Wide (SOFTTW), ened inflammatory response mediated by leukocytes. Methods:
SATS (SATS), Trauma Tourniquet Belt (TTB), and RECON use We conducted a prospective, observational study of 23 consecu-
a windlass to increase circumferential compression by decreasing tive patients with more than 20% body surface area burn injuries,
strap length. The Ratcheting Medical Tourniquet (RMT) and XL who were admitted to our university’s intensive care unit (ICU).
Ratcheting Medical Tourniquet (XLRMT) use a ratchet and lad- We followed these patients for five days (T1–T5) and measured
der mechanism for circumferential compression. their platelet and leukocyte anti-sedimentation rates (PAR and
LAR) using 1-h gravity sedimentation test. These tests determine
We have shown that the majority of tourniquets with non-elastic the percentage of platelets and leukocytes that cross the half line
straps that rely on windlass mechanisms to achieve mechanical ad- of the blood sample column, indicating cells with decreased spe-
vantage in circumferential compression fail when placed on man- cific gravity. Our goal was to investigate the time course of PAR
ikins representing arms of small children. Unfortunately, recent and LAR after burn injury and determine the trend of platelet and
events have shown an increasing frequency of targeting random leukocyte activation in the early post-burn period. Our second
civilians during terrorist incidents. Most emergency medical ser- goal was to compare the change of these parameters in the two
vices (EMS) agencies only carry one brand of tourniquet, with the examined populations. Results: The daily median values of both
CAT being the most common. The tourniquets carried by EMS PAR and LAR continuously increased over the observation period
agencies have been designed for use on healthy adult males in (T1–T5). ICU non-survivors (n=7) had lower daily median PAR
combat. We have shown that these tourniquets may be unable to and LAR values compared to survivors (n=16) between T2 and T4
control hemorrhage in morbidly obese patients. (p<0.05 and p<0.01). At T5, PAR values were lower in septic pa-
tients (n=10) than in non-septic patients (n=13, p<0.01). Conclu-
sions: Our findings suggest that PAR and LAR can serve as novel
bedside tests for predicting septic complications and unfavorable
outcomes after major burn injury. However, further studies with
larger sample sizes are necessary to confirm these results.

2023 CMC Abstracts | 119