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High-flow oxygen is applied while additional
assessment is conducted. One crew member
quickly performs a rapid head-to-toe exam
to discover a second GS W to the left anterior
thigh, which is actively hemorrhaging bright
red blood. The EMS provider immediately
places a tourniquet proximal to the wound
and quickly stops the hemorrhage.
When the crew rolls the patient to assess
his posterior surfaces and place him on a
backboard, they note an exit wound just lateral to the spine at approximately the level of
the eighth rib on the right posterior thorax.
The exit wound is approximately the size of
a quarter. Vital signs include a blood pressure of 108/74, respiration rate of 30 and a
pulse rate of 128 beats per minute (bpm) His
Glasgow Coma Scale score is 14, and he’s
confused about the time and place.
Once inside the ambulance, the patient is
quickly reassessed. The lead medic quickly
places two peripheral IV lines while the unit
is en route to the hospital. During the 15-min-
ute ride, the patient rapidly deteriorates. His
blood pressure drops to 74/50; his heart rate
increases to 144 and respirations are 38. Suspecting a possible tension pneumothorax,
the medic inserts a 14-gauge catheter into the
patient’s chest, and a rush of air ensues. The
lead medic then administers a 500 cc bolus
of normal saline. The patient’s respiratory
rate and pulse immediately decrease, and his
blood pressure improves to 95/50. The lead
medic provides a concise radio report to the
hospital and arrives shortly thereafter, having stabilized this critical patient.
Patients with internal or external bleeding are at risk for developing shock. In some
cases, such as the one illustrated above, the
onset of shock will be rapid. EMS providers need to be able to predict that shock
will occur prior to discovering the hallmark signs. This article will address key
considerations related to determining the
risk of developing shock, detecting shock
when it’s present, and providing rapid
assessments and interventions to improve
AnAtomy & Physiology
The body meets its metabolic demands
through a series of anatomical features and
physiological mechanisms. In the context of
bleeding and shock, the EMS provider must
have a keen awareness of the anatomy and
physiology of the cardiovascular system. It’s
>> Identify major anatomical components
of the cardiovascular system.
>> Describe the physiological components
of blood pressure.
>> Differentiate between compensated,
uncompensated, and irreversible shock.
>> Use a comprehensive assessment to
formulate a treatment plan for a patient
suffering from shock.
Hemorrhagic shock: Shock associated with the
sudden and rapid loss of significant amounts of
blood often caused by severe traumatic injuries. This
results in inadequate perfusion to meet the metabolic
demands of cellular function.
Compensated shock: Category of shock that occurs
early, while the body is still able to compensate
for a shortfall in one or more of the three areas
Uncompensated shock: Category of shock that
occurs when the compensatory mechanisms fail and
the patient’s condition deteriorates.
Irreversible shock: The terminal category of shock
that will lead to the patient’s demise because it can’t
Truncal injury: Injuries pertaining to the chest,
abdomen, or pelvis, where hemorrhage can be difficult
to detect and control for prehospital providers.
equally important to understand how the
system attempts to compensate during times
The heart is at the core of the cardiovascular system. It’s a four-chambered organ that
must constantly pump blood to the lungs
and the body as a whole. Blood is received
in the two superior chambers, known as
the atria. The lower chambers are known
as the ventricles. The right atrium gets its
blood from the inferior and superior vena
cava. The blood is then pumped past the tricuspid valve into the right ventricle, which
then ejects blood through the pulmonary
valve, into the pulmonary artery, where it’s
delivered to the lungs to be oxygenated. The
“fresh” blood will return to the left atrium via
the pulmonary veins.
It will then pass through the mitral valve
into the left ventricle, which is considered
the high-pressure side of the heart. Blood is
ejected from the left ventricle past the aor-
tic valve into the aorta. It’s then distributed
throughout the body.
Blood distriBution &
The body’s distribution system for blood
includes all of the vessels. Arteries, with the
exception of the pulmonary artery, deliver
highly oxygenated blood throughout the
body. These vessels are relatively thick and
are composed of three layers: the tunic
intima (innermost layer), the tunic media
(middle layer), and the tunic adventitia (
The arteries branch off to become smaller
vessels, known as arterioles. These smaller
vessels bring blood to the capillaries, which
are tiny, thin-walled vessels that allow the
diffusion of oxygen and nutrients for the
benefit of the body’s cells. Waste products
are then diffused from the cells into the
venous side of the capillaries. Smaller vessels, known as venules, carry this blood to
the veins. The venous blood is lower in oxygen but not devoid of it. The veins eventually
connect to the vena cava to return the blood
to the heart for its next loop in the cycle.
The blood is composed of both fluid
and formed elements. The fluid is known
as plasma, which contains important proteins, including critical clotting factors. The
formed elements include the red blood cells
(erythrocytes), white blood cells (
leukocytes) and platelets. The leukocytes work to
fight off infections. However, more important to learn about in the context of bleeding
and shock are the erythrocytes and platelets.
When the system works properly, the
body’s cells, tissues and organs are properly
perfused. Perfusion is a complicated process
that can be simplified down to this critical
point: in order for the cells to function properly, they need an adequate flow of oxygen
and nutrients coupled with the need to eliminate harmful waste products. Perfusion is
accomplished when the heart, blood vessels
and blood are working in harmony. Thus, the
heart must be functioning, the blood vessels
must have proper tone (resistance), and an
adequate amount of blood must be present.
EMS providers roughly measure perfusion
by assessing blood pressure. Mathematically,
blood pressure is a product of heart rate
multiplied by stroke volume multiplied by
peripheral vascular resistance.