Trauma lethal triad

1. MSF MOKHA HOSPITAL
THE LETHAL TRIAD OF TRAUMA
Materials from the JEMS article:
Trauma’s Lethal Triad of Hypothermia, Acidosis & Coagulopathy Create a
Deadly Cycle for Trauma Patients
Link: https://www.jems.com/articles/print/volume-39/issue-
4/features/trauma-s-lethal-triad-hypothermia-acidos.html

2. Learning Objectives:
•List the individual components of the lethal triad of
trauma.
•Understand the pathophysiology that makes the
lethal triad a deadly self-propogating cycle in critically
ill trauma patients.
•Learn simple interventions EMS providers can
perform to help prevent or slow the rapid progression
of the lethal triad.

3. Key Terms:
• Acidosis: Lower than normal pH due to increased hydrogen ion
concentration.
• Coagulation system: A temperature- and pH-dependent series of complex
enzymatic reactions that result in the formation of blood clots to stop both
internal and external hemorrhage.
• Coagulopathy: Any disorder of the blood that makes it difficult for blood to
coagulate.
• Hypothermia: Lowered body core temperature.
• Lethal triad: A combination of acidosis, coagulopathy and hypothermia
that usually leads to death in a patient experiencing trauma.

4. • Despite great advancements in trauma care over the past 30 years, trauma is still one
of the leading causes of death in any age group. This is especially apparent in the
young—for those aged 1–44 years old, trauma is the No. 1 cause of death in the
United States.Of these deaths, hemorrhage accounts for up to 40% and remains as
the leading preventable cause of trauma-related death.
• The lethal triad of hypothermia, acidosis and coagulopathy has been recognized as a
significant cause of death in patients with traumatic injuries. In 1982, a study
described a “bloody vicious cycle” in which hemorrhage and tissue injury cause this
predictable triad of complicating factors. Ultimately, this triad resulted in worsening
hemorrhage and eventual death. Authors of the research suggested treatment of
hypothermia, acidosis and coagulopathy in trauma requires as much attention as the
traditionally emphasized surgical management of injuries.
Trauma & the Triad:

5. Today, we recognize that to successfully resuscitate the
critically ill trauma patient, all emergency providers
must have a firm understanding of the lethal triad. This
understanding should serve as the cornerstone for all
interventions provided to the bleeding trauma patient.
Left untreated, hypothermia, acidosis and coagulopathy
bring about and propagate each other, eventually
resulting in a predictable but irreversible progression
toward death.
Trauma & the Triad:

7. • Normal human body temperature is 35.6–37 degrees C with
hypothermia being defined as a core temperature < 35 degrees C.
• Hypothermia in trauma patients is caused by a multitude of factors.
Hemorrhagic shock, traumatic brain injuries impair the body’s ability
to regulate its core temperature.
• Even mild hypothermia in a trauma patient can result in devastating
physiologic consequences. Of particular concern is the effect of
hypothermia on the coagulation system.
• Room temperature normal saline (20–25 degrees C) is very
hypothermic relative to the desired normal body temperature. Thus,
large volume resuscitations with even room temperature IV fluids
can significantly contribute to this arm of the lethal triad.
Hypothermia:

9. • Acidosis is defined as an arterial pH < 7.35 and can result from a variety of
disease states. However, in trauma patients the major contributor is poor
perfusion to the tissues.
• Anemia from acute blood loss, peripheral vasoconstriction in response to
hypothermia and blood loss, and overall decreased cardiac output severely
impair oxygen delivery to the tissues. Lastly, a trauma patient may also have
respiratory acidosis. This is a result of hypoventilation due to respiratory
depression or obstruction resulting in hypercapnia (increased CO2 levels).
Common causes of a respiratory acidosis in trauma include narcotic or alcohol
use, traumatic brain injuries, flail chest or preexisting medical conditions such
as chronic obstructive pulmonary disease.
• As a trauma patient’s perfusion worsens, lactic acid rapidly accumulates in the
tissues. This causes the body’s pH to drop, resulting in a severe metabolic
acidosis. It’s important to note that this process frequently occurs in the
presence of normal or only slightly abnormal vital signs.
Acidosis:

10. • The coagulopathy of trauma occurs not only because of hypothermia and
acidosis as previously discussed, but also as a result of losing clotting factors
through hemorrhage and hemodilution, and the body’s use and subsequent
depletion of both platelets and clotting factors.
• Dilutional coagulopathy occurs when we resuscitate a bleeding trauma patient
with fluid or blood products that don’t contain the same clotting factors lost in
the acutely hemorrhaged whole blood.
• Lastly, EMS providers should be aware of those trauma patients who have a
baseline coagulopathy because of preexisting medical conditions. Examples
include those patients on anticoagulant therapy such as warfarin (Coumadin)
or a novel oral anticoagulant such as dabigatran for stroke prevention in the
setting of atrial fibrillation. These patients and those with chronic liver or renal
failure have an increased risk of developing a truly life-threatening
coagulopathy and hemorrhage after trauma.
Coagulopathy:

14. Management of the Lethal
Triad:
• The triad begins and ends with bleeding, so find the bleeding and stop it. Do not stop your
search for bleeding with the first source you find, as others may exist.
• Always assume your patient’s temperature is dropping right before your eyes, because it is,
and much faster than you’d expect. If you aren’t sweating, it’s certainly not warm enough.
(Ideally, 27 degrees C.). Cover the patient! Promptly remove wet or bloody clothes and replace
with a warm blanket. Shivering wastes valuable cellular energy and oxygen in an attempt to
stay warm while producing more lactate, contributing to acidosis.
• Maximaze oxygenation: oxygen mask for all.
• Monitor: trauma vitals signs running fast.
• Administer tranexamic acid (TXA)—an antifibrinolytic that prevents clot breakdown and thus
decreases blood loss—if your system permits its use.
• We don’t bleed normal saline, so limit crystalloid infusion as much as possible. It contributes to
the patient’s acidosis and dilutes the remaining clotting factors in your patient’s blood. IV
fluids may improve a number, but may actually hurt your patient in the long run.
• Except in those patients with a traumatic brain injury, utilize a permissive hypotension
resuscitation strategy. Our goal should be to maintain tissue perfusion typically defined as the
presence of a radial pulse or normal mental status. We should avoid overly aggressive fluid
administration to normalize blood pressure, which can “pop the clot” and worsen hemorrhage.
• Whenever possible, administer only warmed fluids. (Ideally 40 degrees C.)