While I was in Afghanistan (2014-2015), I researched and wrote an article regarding the advances in trauma care that have resulted in our wars in Iraq and Afghanistan. I intended to publish this in Advance for PA's and NP's when I came home, but neglected to pursue submission due to other priorities and my inability to contact Mike at Merion Publishing. I'm going to post the article here on my blog site, if for nothing else than to show I did actually write it and maybe someone will still get some practical benefit. I would also like to point out that some of these lessons were instrumental in the phenomenal work of the Trauma staff in Las Vegas who were able to save many lives in the 2017 mass shooting there.
Lessons
from the Battlefield: Damage Control Surgery, Resuscitation and
Tranexamic Acid (TXA) in Trauma Care
Roger S. Best,
EMPA-C, MPAS
If anything beneficial has ever
come from modern warfare, it has been the improvements in the survival rate of
severely injured combat casualties. These
benefits eventually ring down to traumatically injured patients in the civilian
world. The wars in Iraq and Afghanistan
have brought several major advances in trauma care1: damage-control surgery (DCS), damage-control
resuscitation (DCR), and the use Transexamic acid (TXA) in patients with
massive hemorrhage. This article addresses these modalities, beginning with
damage control surgery.
The concept of DCS2,3 has been evolving
since the 1990’s, but with lessons learned during the wars in Iraq and
Afghanistan, the concept and practice of damage-control surgery has rapidly
advanced in the war-time theater. These
practices are now gaining acceptance in civilian trauma care settings as well. In DCS, patients are initially evaluated and
receive any indicated emergent life-saving interventions (LSIs), i.e.
definitive airway management, thoracostomy, initial resuscitation for
hypovolemia, etc. Once these have been
performed, the patient is then taken to the operating suite for initial
surgical interventions that are specifically designed to: 1) control hemorrhage;
2) prevent or mitigate contamination, and 3) protect the patient from further
injury.
It is now well-established that
trauma patients surviving their initial injuries are more likely to die from
severe metabolic derangements than from the failure to complete the surgical
repair(s) of their injuries. These
derangements, referred to as the “lethal triad,” include coagulopathies, which
impair hemorrhage control, hypothermia and metabolic acidosis.* Once
these derangements are established, their management becomes problematic.
Ironically, prolonged surgical procedures to complete repairs of injuries are major
contributors to these derangements and to the corresponding increase in delayed
patient mortality. This realization
requires a shift in the surgical mindset, where conventional surgical wisdom dictated
that surgery is best provided as a single definitive procedure to one of staged
surgical intervention(s).
Our collective wartime experience
now shows that the best patient outcomes result from initial life-saving
interventions, followed by abbreviated, staged surgical procedures,
particularly laparotomy, to control hemorrhage, prevent further contamination
and protect the patient from further injury.
Once these initial goals are accomplished, the patient is then
transferred to the intensive care setting for management of coagulopathy, hypothermia
and metabolic acidosis. Once the
patient’s physiologic condition has been optimized, they can be returned to the
OR for completion of surgical care. Best
practices in trauma care now dictate a continuum of staged surgical
interventions, interspersed with ICU care in order to optimize the patient’s medical
condition between interventions.
Damage Control Resuscitation
(DCR)3,4, is emergent
medical care provided to treat or mitigate the impact of coagulopathies,
hypothermia and metabolic acidosis, either in concert with DCS, or while the
patient is awaiting surgical intervention.
The initial, and most important aspect of DCR, is to optimize the control of hemorrhage. Death from hemorrhage accounts for 30-45% of
trauma deaths, but paradoxically is the most preventable cause of death among
combat casualties.
In contrast to previous
approaches initially using direct pressure, elevation and proximal arterial pressure
points for the control severe bleeding, the methods best proven for the control
of potentially life threatening hemorrhage should be limited to direct pressure
to compressible bleeding sites, the use of hemostatic dressings, and the
effective use of tourniquets.
Direct pressure remains the
mainstay of initial hemorrhage control measures. Hemostasis can be achieved
quickly with a compressible wound. Hemostatic
dressings used in conjunction with pressure are highly effective. In cases where an extremity injury results in
severe bleeding and these techniques will not quickly bring this under control,
then proximal application of a tourniquet is the intervention of choice. In the
wartime experience, the use of tourniquets have shown several advantages, where
the prehospital time is under six (6) hours, including:
·
Improved hemorrhage control
·
Decreased incidence of shock
·
Improved survival
·
Acceptably low rate of tourniquet-related
complications
Non-traditional tourniquets
(junctional tourniquets) have also been developed and have shown success in
controlling hemorrhage from typically non-compressible sites, such as the iliac
and axillary arteries5. In areas of hemorrhage where bleeding is
occurring from inaccessible sites, i.e. Pelvic fractures, non-compressible
injuries not amenable to tourniquet application, therapies such as pelvic
binders and also hemostatic dressings (i.e. Combat Gauze) have shown some
benefit. Ultimately, the goal of using
more aggressive methods of hemorrhage control are intended to reduce the need
for massive transfusion and address the resultant risk of coagulopathy.
Predictive indicators of the need for transfusion therapy include penetrating
injuries to the trunk, systemic hypotension (SBP<90 and="" core="" hg="" hypothermia="" mm="">36°C or 96°F). However,
data from the National Trauma Data Bank has shown increased mortality with SBP of
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·
Base deficit > 6 or pH < 7.25
·
INR > 1.5
·
Hemoglobin <11 hematocrit="" o:p="" or="">
Even with what would have
previously been considered “stable” levels of SBP (90-118 mm/hg), the insidious
onset of the shock state can be seen in the increasing base deficit, declining
pH, declining H&H values, and the early onset of coagulopathy.
The next component of DCR is the prevention of hypothermia, which
increases the risk of life-threatening hemorrhage and associated mortality, with
a death rate of 100% in severe cases.
Strategies to combat the incidence and degree of hypothermia in the prehospital
setting by focusing on hemorrhage control, limiting the amount of clothing
removed, instituting passive warming techniques such as the use of wool, solar
and warming blankets and the infusions warmed IV fluids. Passive and active anti-hypothermic measures
should be continued in the emergency and intensive care settings.
The final component of DCR is the
management of hypotension, transfusion considerations and the mitigation of
metabolic derangements. Ideally, the
goal would be to address all of these derangements simultaneously. In prehospital settings, or at facilities
where appropriate surgical services are not readily available, consideration
should be given to “hypotensive resuscitation” in selected cases.
In hypotensive resuscitation,
aggressive hemorrhage control of active bleeding is the focus, along with vascular
access and conservative intravenous fluid administration, while a
lower-then-normal SBP is permitted. The
intention is to avoid rebleeding and dilutional coagulopathy until surgical
control of hemorrhage can be accomplished. This approach uses the body’s natural
coagulation cascade, vascular spasm secondary to injury, and a degree is
hypotension (SBP <90 1="" 2="" a="" and="" animal="" are="" b="" be="" beneficial:="" by="" care.="" cases="" clearly="" cns="" combat="" controlled="" current="" delayed="" felt="" field="" further="" hemorrhage="" hg="" hospitals="" however="" hypotension="" hypotensive="" immediately="" in="" indicated="" is="" mitigate="" mm="" nbsp="" non-compressible="" not="" of="" only="" operations="" operative="" or="" patient="" permissive="" practices="" quickly="" reaching="" reflects="" resuscitation="" s="" situations="" studies="" support="" surgical="" taken="" teams="" the="" there="" to="" trauma="" two="" war="" well-supported="" where="" will="" with="" zones.="">6
or in cases of impending vascular collapse.
Where hypotensive resuscitation
is not indicated, intravenous therapy may be instituted to support
circulation. Traditionally, crystalloid
solutions such and normal saline (NS) or lactated ringer’s solution (LR) have
been used for initial resuscitation. In
animal studies of these fluids in the treatment of traumatic shock, NS was
shown to contribute to metabolic acidosis and worsening coagulopathy, whereas
this was not observed using LR. Theoretically, either fluid in significant
volume (>20 mL/kg) may result in dilutional coagulopathy, and while LR has
been shown to be superior in animal models for trauma resuscitation, neither
fluid is ideal and the administration of greater than 20 mL/kg is of dubious
benefit. Colloidal solutions, such as
HES (Hetastarch) also contribute to dilutional coagulopathy, but has the added
disadvantage of impairing the plasma activity of von Willebrand factor7. These effects would make such solutions
undesirable for resuscitation in the setting of continuing hemorrhage.
Vasopressor agents, though widely
used in medical shock states, are generally eschewed in the case of acute
hemorrhagic shock. However, an
exception may be the use of low-dose vasopressin, which apparently becomes
deficient in advanced stages of hemorrhagic shock. Theoretically, vasopressin may lower overall
resuscitation volumes is hemorrhagic shock, reducing morbidity and mortality,
but there are currently no studies to support its use. Promising studies thus have shown enhanced
survival from lethal hemorrhage in porcine subjects8
and reduced fluid resuscitation volumes in human subjects. More extensive human
trials are planned involving the use of vasopressin in trauma.
The resuscitation fluids of
choice for hemorrhagic shock include whole blood, or combination blood
component therapy. Whole blood has the
advantage of volume replacement with an equivalent oxygen-carrying substitute,
while concomitantly addressing coagulation deficiencies. In the absence of whole blood, component
therapy at a 1:6:6* ratio of platelets, PRBCs and fresh-frozen plasma
respectively is the currently preferred option until patient stabilization has
been obtained9.
*Concentrated platelets are equivalent to the number of
platelets contain in 6 units of whole blood.
Administration of a unit of concentrated platelets per 6 units of PRBCs
and FFP is equal to a blood component transfusion ratio of 1:1:1.
Massive transfusion is generally
considered as the administration of 10 or more units of blood within a 24-hour
period. During massive transfusion, the
patient will need to be under continuous surveillance for associated
transfusion-related complications, including potential hyperkalemia and
hypocalcemia, and treated accordingly10.
In patients who receive massive
transfusion therapy, the early use of Transexamic acid (TXA) has been shown to
improve survival11. TXA is an Antifibrinolytic agent that exerts a
protective effect against the onset of coagulopathies (i.e. DIC). Studies using
TXA in the setting of combat trauma have demonstrated improvements in long-term
patient survival, despite higher injury severity scores in TXA-treated
casualties requiring massive transfusion if TXA is administered within 3 hours
following an injury12.
Advances in the care of trauma
victims continue to evolve from our dynamic experiences with combat
casualties. Simply getting the patient
into the surgical suite is no longer the gold standard of care, but rather a
part of a balanced multi-disciplinary approach that includes life-saving
pre-hospital and emergency department therapies, staged surgical interventions,
and intensive care optimization that will provide more substantial reductions
in mortality and morbidity than seen previous decades.
1. Howell SJ. Advances in
trauma care: a quiet revolution. British
Journal of Anaesthesia (2014) 113 (2): 201-202
2.
Wyrzykowski AD,
Feliciano DV: Trauma damage control. In Trauma. 6th
edition. 2008: 851-870. 
3. Lenhart
MK., Savitsky E., Eastridge B., Combat
Casualty Care: Lessons Learned from OEF and OIF. Office of the Surgeon
General, U.S. Army. Borden Institute, Fort Detrick MD. 2014.
4. McLamb
CM, MacGoey P, Navarro, AP, Brooks AJ. Damage control surgery in the era of damage control
resuscitation. British Journal
of Anaesthesia; (2014) 113 (2): 242-249.
5. Kotwal, Russ
S., et al. Management of Junctional
Hemorrhage in Tactical Combat Casualty Care: TCCC Guidelines–Proposed Change
13-03. Journal of Special
Operations Medicine; 13.4
(2013): 85-93.
6. Brain Trauma Foundation; American Association of
Neurological Surgeons; Congress of Neurological Surgeons; et al. Guidelines for the management of severe
traumatic brain injury. I. Blood pressure and oxygenation. Journal of Neurotrauma 2007; 24 (1
Supplement): S7-13.
7.
Treib J, Haass A, Pindur G. Coagulation disorders caused by hydroxyethyl starch. Thromb Haemost;
1997; 78(3): 974-983.
8.
Karl H. Stadlbauer, M.D., Horst G.
Wagner-Berger, M.D., et al. Vasopressin,
but Not Fluid Resuscitation, Enhances Survival in a Liver Trauma Model with
Uncontrolled and Otherwise Lethal Hemorrhagic Shock in Pigs. Anesthesiology; 2003; 98: 699–704
9.
Ho AM, Dion PW, Cheng CA, et al. A mathematical model for fresh frozen
plasma transfusion strategies during major trauma resuscitation with ongoing
hemorrhage. Canadian Journal of
Surgery 2005; 48(6): 470-478.
10.
Kristen C. Sihler, MD, MS; Lena M. Napolitano,
MD. Complications of
Massive Transfusion. Chest; 2010;
137(1): 209-220.
11.
Rappold JF, Pusateri AE. Tranexamic acid in remote damage control
resuscitation. Transfusion. 2013 Jan; 53 (Supplement 1): 96S-99S.
12. Olldashi F, Kerci M, et
al. The importance of early
treatment with tranexamic acid in bleeding trauma patients: An exploratory
analysis of the CRASH-2 randomised controlled trial. The Lancet 2011; 377 (9771)
Roger Scott Best, EMPA-C, MPAS
Emergency Medicine Physician Assistant
Bagram Air Field, Afghanistan - Providing medical services
in support of 401st Army Field Support Brigade
Lives in Garner, North Carolina.
