Transcript Shock and Hemorrhage - McLaren

Division 3
Trauma Emergencies
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Chapter 19
Hemorrhage and Shock
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Topics
Introduction to Hemorrhage and Shock
Hemorrhage
Shock
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Introduction to
Hemorrhage and Shock
Hemorrhage
– Abnormal internal or external loss of
blood
Homeostasis
– Tendency of the body to maintain a
steady and normal internal environment
Shock
– INADEQUATE TISSUE PERFUSION
– Transition between homeostasis and
death
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Hemorrhage
Circulatory System
Hemorrhage Classification
Clotting
Factors Affecting Clotting
Hemorrhage Control
Stages of Hemorrhage
Hemorrhage Assessment
Hemorrhage Management
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Cardiac Anatomy
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Heart
Cardiac Cycle
– The repetitive pumping action that
produces pressure changes that circulate
blood throughout the body
Cardiac Output
– The total amount of blood separately
pumped by each ventricle per minute,
usually expressed in liters per minute
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Cardiac Output
Normal cardiac output = 5 to 6 liters per
minute (LPM)
Can increase up to 30 LPM in times of
stress or exercise
Determined by multiplying the heart rate by
the volume of blood ejected by each
ventricle during each beat (stroke volume)
CO is influenced by:
– Strength of contraction
– Rate of contraction
– Amount of venous return available to the
ventricle (preload)
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Circulatory System (1 of 4)
Heart
– Autonomic nervous system
Parasympathetic nervous system
Slows rate
Mediated by vagus nerve
Sympathetic nervous system
Increases rate
Cardiac plexus
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Circulatory System (2 of 4)
Key Terms
Stroke Volume
Preload
Ventricular Filling
Starling’s Law of the Heart
Afterload (End Diastolic Pressure or EDP)
Cardiac Output
– SV x HR
– 5 liters/minute
Fick Principle
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Circulatory System (3 of 4)
Arteries
– Tunica Adventitia
– Tunica Media
– Tunica Intima
}
13% of blood volume
Arteriole
Capillary: 7% of total blood volume
Venule
64% of blood volume
Vein
}
– Constriction returns 20% (1 liter) of blood to
active circulation
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Circulatory System (4 of 4)
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Cardiac Physiology
Pulmonary
Arteries
Vena Cava
and
Systemic
Veins
Right
Atrium
Left
Ventricle
Systemic
Capillaries
LUNGS
Right
Ventricle
Left
Atrium
Pulmonary
Veins
Aorta
and
Systemic
Arteries
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Circulation (1 of 2)
Systolic Pressure
– Strength and volume of cardiac output
Diastolic Pressure
– More indicative of the state of constriction
of the arterioles
Mean Arterial Pressure
– 1/3 pulse pressure added to the diastolic
pressure
– Tissue perfusion pressure
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Circulation (2 of 2)
Vascular Control
– Increased sympathetic tone results in
increased vasoconstriction
Microcirculation
– Blood flow in the arterioles, capillaries,
and venules
– Sphincter functioning
Most organ tissue requires blood flow
5 to 20% of the time.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Cardiac Physiology (1 of 2)
Oxygen Supply
– The myocardium receives its blood/oxygen
supply during the diastole phase of contraction.
The blood flows from the aorta through the two
coronaries into the relaxed myocardium.
Oxygen Demand
– 90% of the O2 demand, or work, of the heart is
performed during the isovolumetric phase of
contraction. In this phase, NO blood flows from
the heart into the aorta, until the pressure in the
heart is greater than the end diastolic pressure
(EDP).
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Cardiac Physiology (2 of 2)
Releases a polypeptide called atrial
natriuretic peptide (ANP)
Works antagonistically to renin-angiotensin
Four Effects
– Promotes Na+ and water loss at the kidneys
– Inhibits renin release and ADH, aldosterone
secretion
– Suppresses thirst
– Blocks action of angiotensin II and
norepinephrine
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Negative Feedback
Important negative feedback
mechanisms in maintaining tissue
perfusion are the:
– Baroreceptor reflexes
– Central nervous system ischemia
responses
– Hormonal mechanisms
– Reabsorption of tissue fluids
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Cardiovascular System
Regulation (1 of 3)
PNS and SNS always act in balance
Baroreceptors: monitor BP
Chemoreceptors
Hormone regulation
Reabsorption of tissue fluids
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© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Cardiovascular System
Regulation (2 of 3)
Parasympathetic Nervous System
Decrease
– Heart rate
– Strength of contractions
– Blood pressure
Increase
– Digestive system
– Kidneys
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© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Cardiovascular System
Regulation (3 of 3)
Sympathetic Nervous System
Increase
–
–
–
–
Body activity
Heart rate
Strength of contractions
Vascular constriction
Bowel and digestive viscera
Decreased urine production
– Respirations
– Bronchodilation
Increases skeletal muscle perfusion
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© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Baroreceptor Reflexes (1 of 5)
High in the neck, each carotid artery divides
into external and internal carotid arteries.
– At the bifurcation, the wall of the artery is thin
and contains many vine-like nerve endings.
The small portion of the artery is the carotid
sinus.
– Nerve endings in this area are sensitive to
stretch or distortion.
Serve as pressure receptors or baroreceptors.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Baroreceptor Reflexes (2 of 5)
Similar area found in the arch of the aorta.
– Serves as a second important baroreceptor
Large arteries, large veins, and the wall of
the myocardium also contain less important
baroreceptors.
Baroreceptor reflexes help maintain blood
pressure by two negative feedback
mechanisms:
– By lowering blood pressure in response to
increased arterial pressure
– By increasing blood pressure in response to
decreased arterial pressure
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Baroreceptor Reflexes (3 of 5)
Normal blood pressure partially stretches the
arterial walls so that baroreceptors produce a
constant, low-frequency stimulation.
Impulses from the baroreceptors inhibit the
vasoconstrictor center of the medulla and
excite the vagal center when blood pressure
increases.
– Results in vasodilation in the peripheral circulatory
system and a decrease in the heart rate and force
of contraction.
Combined effect is a decrease in arterial pressure.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Baroreceptor Reflexes (4 of 5)
Baroreceptors adapt in 1 to 3 days to
whatever pressure level they are
exposed. Therefore, they do not
change the average blood pressure on
a long-term basis. This adaptation is
common in people who have chronic
hypertension.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Baroreceptor Reflexes (5 of 5)
When baroreceptor stimulation ceases due
to a fall in arterial pressure, several
cardiovascular responses are evoked:
– Vagal stimulation is reduced and sympathetic
response is increased.
– The increase in sympathetic impulses results in
increased peripheral resistance and an increase
in heart rate and stroke volume.
Sympathetic discharges also produce generalized
arteriolar vasoconstriction, which decreases the
container size.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
The vasoconstriction in peripheral
vascular beds results in the
characteristic pale, cold skin of patients
suffering from hypovolemic shock.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Chemoreceptor Reflexes
Chemoreceptors
– Monitor level of CO2 in CSF
– Monitor level of O2 in blood
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Chemoreceptor Physiology
Low arterial pressure leads to hypoxemia
and/or acidosis.
Hypoxemia/acidosis stimulate peripheral
chemoreceptor cells within the carotid and
aortic bodies.
– These bodies have an abundant blood supply.
When oxygen or pH decreases, these cells
stimulate the vasomotor center of the
medulla.
– The rate and depth of ventilation are also
increased to help eliminate excess carbon
dioxide and maintain acid-base balance.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
CV System and Hormone
Regulation (1 of 7)
Catecholamines
– Epinephrine
– Norepinephrine
– Actions
Alpha 1
Alpha 2
Beta 1
Beta 2
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
CV System and Hormone
Regulation (2 of 7)
Alpha 1
– Vasoconstriction
– Increased
peripheral vascular
resistance
– Increased preload
Alpha 2
– Regulates release
of NE
Beta 1
– Positive inotropy
– Positive
chronotropy
– Positive
dromotropy
Beta 2
– Bronchodilation
– Smooth muscle
dilation in bowel
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
CV System and Hormone
Regulation (3 of 7)
Antidiuretic Hormone (ADH)
– AKA: Arginine Vasopressin (AVP)
– Release
Posterior pituitary
Drop in BP or increase in serum osmolarity
– Action
Increase in peripheral vascular resistance
Increase water retention by kidneys
Decrease urine output
Splenic vasoconstriction
200 mL of free blood to circulation
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
CV System and Hormone
Regulation (4 of 7)
Angiotensin II
– Release
Primary chemical from kidneys
Lowered BP and decreased perfusion
– Action
Converted from renin into angiotensin I
Modified in lungs to angiotensin II
20-minute process
Potent systemic vasoconstrictor
1-hour duration
Causes release of ADH, aldosterone, and
Bledsoe et al., Essentials of Paramedic Care: Division 1II
epinephrine
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CV System and Hormone
Regulation (5 of 7)
Aldosterone
– Release
Adrenal cortex
Stimulated by angiotensin II
– Action
Maintain kidney ion balance
Retention of sodium and water
Reduce insensible fluid loss
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
CV System and Hormone
Regulation (6 of 7)
Glucagon
– Release
Alpha cells of pancreas
Triggered by epinephrine
– Action
Causes liver and skeletal muscles to convert
glycogen into glucose
Gluconeogenesis
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© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
CV System and Hormone
Regulation (7 of 7)
Insulin
– Release
Beta cells of
pancreas
– Action
Facilitates transport
of glucose across
cell membrane
Erythropoietin
– Release
Kidneys
Hypoperfusion or
hypoxia
– Action
Increases
production and
maturation of RBCs
in the bone marrow
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Reabsorption of Tissue Fluids
(1 of 2)
Arterial hypotension, arteriolar constriction,
and reduced venous pressure during
hypovolemia lower the blood pressure in the
capillaries (hydrostatic pressure).
The decrease promotes reabsorption of
interstitial fluid into the vascular
compartment.
– Considerable quantities of fluid may be drawn
into the circulation during hemorrhage.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Reabsorption of Tissue Fluids
(2 of 2)
Approximately 0.25 mL/min/kg of body
weight (1 L/hr in the adult male) can be
autotransfused from the interstitial
spaces after acute blood loss.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Vasculature
Lined with smooth muscle.
All vessels larger than capillaries have
layers of tissues (tunicae).
Maintains blood flow by changes in
pressure and peripheral vascular
resistance.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Vascular Pressure Gradients
Fluid flows through a tube in response
to pressure gradients between the two
ends of the tube.
It is not the absolute pressure in the
tube that determines flow, but the
difference in pressure between the two
ends.
In humans, the two ends are the aorta
and the vena cava.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Vasculature
Measurements of pressure in the
vascular system:
– Systemic pressure
(Left-sided pressure)
– Pulmonic pressure
(Right-sided pressure)
Systemic pressure, like pulmonic
pressure, has two phases: systolic
and diastolic.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Diastolic Blood Pressure
Diastolic blood pressure is a reflection
of peripheral vascular resistance.
– Pulse pressure is the difference between
these two pressures.
– Pressure is greatest at its origin (the
heart) and least at its terminating point
(the vena cavae).
– This pressure gradient changes
significantly at the arteriole because of
peripheral vascular resistance.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Peripheral Vascular
Resistance (Afterload)
The total resistance against which blood
must be pumped.
It is essentially a measure of friction
between the vessel walls and fluid, and
between the molecules within the fluid itself
(viscosity).
– Both oppose flow.
When resistance to flow increases, blood
pressure must increase for the flow to
remain constant.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Starling’s Law of the Heart
When the rate at which blood flows into the
heart from the veins (venous return)
changes, the heart automatically adjusts its
output to match inflow.
The more blood the heart receives the more
it pumps…
– Increased end diastolic volume increases
contractility.
– Increases stroke volume.
– Increases cardiac output.
Starling curves at any end-diastolic volume.
Increased sympathetic input increases stroke volume.
Decreased sympathetic input decreases stroke
volume.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Resistance to Blood Flow
Increases with…
Increased fluid viscosity
Increased vessel length
Decreased vessel diameter
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Viscosity
The physical property of a liquid
characterized by the friction between
its component molecules (e.g.,
between the blood cells and between
the plasma proteins)
Normally plays a minor role in blood
flow regulation as it remains constant
in healthy people
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Blood Flow Resistance (1 of 2)
Arteries are large and offer little
resistance to flow unless they have an
abnormal narrowing (stenosis).
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© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Blood Flow Resistance (2 of 2)
Arterioles have a much smaller
diameter and offer the major
resistance to blood flow.
– Smooth muscles in the arteriole walls can
relax or contract.
– Can change the diameter of the vessel
as much as fivefold.
– Arterial blood pressure is regulated
primarily by the vasoconstriction or
vasodilation of these vessels.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Microcirculation (1 of 3)
Can be divided into pulmonary
microcirculation and peripheral
microcirculation.
Pressure in each division is produced
by the right and left heart, respectively.
Approximately 5% of the total
circulating blood flow is always flowing
through capillaries.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Microcirculation (2 of 3)
Venules and
veins serve as
collecting
channels and
storage vessels
(capacitance).
Normally contain
70% of the blood
volume.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Microcirculation (3 of 3)
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Mechanisms That Control
Blood Flow
Local control of blood flow by the
tissues
Nervous control of blood flow
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© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Local Control
Blood usually flows through capillaries
intermittently due to:
– The pulsatile manner of blood flow
resulting from cardiac pumping action
and vasomotion
– The intermittent constriction and dilation
of arterioles and precapillary sphincters
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Vasomotion (1 of 3)
Regulated primarily by the
concentration of oxygen in the tissues.
When oxygen concentration is low, the
cells lining and adjacent to the closed
capillaries secrete histamine, which is
thought to be responsible for arteriolar
smooth muscle vasodilation, causing
the capillary to open.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Vasomotion (2 of 3)
Histamine is quickly destroyed in the
blood and does not enter the general
circulation.
As cells become reoxygenated they
stop the histamine secretion, and the
capillary closes.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Vasomotion (3 of 3)
A decrease in oxygen concentration
leads to a local release of vasodilating
substances, which allows blood flow to
increase.
– This in turn increases the delivery of
oxygen and restores aerobic metabolism.
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© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Nervous control of
circulation is accomplished
by negative feedback
mechanisms.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
CNS Ischemia Response
CNS ischemia response is activated when
blood flow to the vasomotor center of the
medulla is decreased.
– In the presence of ischemia, the neurons within
the medulla stimulate the sympathetic nervous
system.
Sympathetic vasoconstriction can elevate
arterial pressure for as long as 10 minutes.
The cerebral ischemia response functions
only in emergency situations.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Blood and Blood Components
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Blood
Blood Volume
– Average adult male has a blood volume
of 7% of total body weight.
– Average adult female has a blood volume
of 6.5% of body weight.
– Normal adult blood volume is 4.5–5 L.
Remains fairly constant in the healthy body.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Blood Components (1 of 2)
Erythrocyte: 45%
– Hemoglobin
– Hematocrit
Miscellaneous blood products: <1%
– Platelets
– Leukocytes
Monocytes, basophils, esonophils,
neutrophils
Plasma: 54%
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Blood Components (2 of 2)
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© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Plasma (1 of 2)
Approximately 92% water
– The liquid portion of blood
Circulates salts, minerals, sugars, fats,
and proteins throughout the body
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© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Plasma (2 of 2)
Contains 3 major proteins:
– Albumin
Most plentiful plasma protein
Similar in consistency to egg whites
Gives blood its gummy texture
Helps keep water concentration of blood low enough
to allow water to diffuse readily from tissues into blood
– Globulins serve 2 main functions:
Alpha and beta globulins transport other proteins
Gamma globulins give people immunity to disease
– Fibrinogen
Aids in blood clotting by forming a web of protein fibers
that binds blood cells together
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© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Other Functions of Plasma
Proteins function as an acid or base to
correct changes in blood acidity.
Can temporarily meet nutritional need
of the body should the body run short
of food.
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© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Proteins
Account for 50% of the body’s organic
material
– Components of most body structures
– Roles in the chemical reactions in the body
Specialized proteins are responsible for:
–
–
–
–
–
Immune responses
Coagulation
Digestion of foodstuffs
Metabolism of nutrients
Many other functions
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Erythrocytes (RBCs)
Transport 99% of blood oxygen.
– Remaining 1% carried in plasma
Make up approximately 45% of the blood
and are the most abundant cells in the body.
Provide oxygen to tissues and remove
carbon dioxide.
Each RBC contains approximately 270
million hemoglobin molecules.
– Allow RBCs to pick up oxygen in the lungs and
release it to body tissues
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Leukocytes (WBCs)
Defend the body against various
pathogens (bacteria, viruses, fungi,
and parasites)
Produced in bone marrow and lymph
glands
– Release reserves when pathogens
invade the body
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© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Platelets
Part of the body’s defense mechanism
Formed in red bone marrow
Work by swelling and adhering
together to form sticky plugs (initiating
the clotting phenomenon)
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© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Clotting (1 of 2)
Three-Step Process
– Vascular phase
Vasoconstriction
– Platelet phase
Tunica intima damaged
Turbulent blood flow
Frictional damage to platelets
Agglutination and aggregation
– Coagulation
Release of enzymes
Extrinsic – nearby tissue
Intrinsic – damaged platelets
Fibrin release
Normal coagulation in 7–10 minutes
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© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Clotting (2 of 2)
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© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Factors Affecting Clotting (1 of 2)
Movement of the wound site
Aggressive fluid therapy
– Increased BP and displaced clots
– Dilution of clotting factors
Low body temperature
– Ineffective clot formation
Medications
– ASA, heparin, Ticlid, warfarin (Coumadin)
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Factors Affecting Clotting (2 of 2)
Nature of the wound
– Transverse (clean tear)
Vessels constrict and draw
inward
Reduction of the lumen
Reduction of blood loss
– Longitudinal (crush injury)
Constriction of the smooth
muscle
Enlarges the wound
Increases blood loss
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© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Stages of Shock
Cellular Level
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Four Stages
Stage 1: Vasoconstriction
Stage 2: Capillary and venule opening
Stage 3: Disseminated intravascular
coagulation
Stage 4: Multiple organ failure
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© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Stage 1: Vasoconstriction (1 of 4)
Vasoconstriction begins as minimal
perfusion to capillaries continues.
– Oxygen and substrate delivery to the
cells supplied by these capillaries
decreases.
– Anaerobic metabolism replaces aerobic
metabolism.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Stage 1: Vasoconstriction (2 of 4)
Production of lactate and hydrogen
ions increases.
– The lining of the capillaries may begin to
lose the ability to retain large molecular
structures within its walls.
– Protein-containing fluid leaks into the
interstitial spaces (leaky capillary
syndrome).
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Stage 1: Vasoconstriction (3 of 4)
Sympathetic stimulation produces:
– Pale, sweaty skin
– Rapid, thready pulse
– Elevated blood glucose levels
The release of epinephrine dilates coronary,
cerebral, and skeletal muscle arterioles and
constricts other arterioles.
– Blood is shunted to the heart, brain, skeletal
muscle, and capillary flow to the kidneys and
abdominal viscera decreases.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Stage 1: Vasoconstriction (4 of 4)
If this stage of shock is not treated
by prompt restoration of circulatory
volume, shock progresses to the
next stage.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Stage 2: Capillary and Venule
Opening (1 of 5)
Stage 2 occurs with a 15% to 25%
decrease in intravascular blood
volume. Heart rate, respiratory rate,
and capillary refill are increased, and
pulse pressure is decreased at this
stage. Blood pressure may still be
normal.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Stage 2: Capillary and Venule
Opening (2 of 5)
As the syndrome continues, the
precapillary sphincters relax with some
expansion of the vascular space.
Postcapillary sphincters resist local
effects and remain closed, causing
blood to pool or stagnate in the
capillary system, producing capillary
engorgement.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Stage 2: Capillary and Venule
Opening (3 of 5)
As increasing hypoxemia and acidosis lead
to opening of additional venules and
capillaries, the vascular space expands
greatly.
– Even normal blood volume may be inadequate
to fill the container.
The capillary and venule capacity may
become great enough to reduce the volume
of available blood for the great veins and
vena cava.
– Resulting in decreased venous return and a fall
in cardiac output.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Stage 2: Capillary and Venule
Opening (4 of 5)
Low arterial blood pressure and many open
capillaries result in stagnant capillary flow.
Sluggish blood flow and the reduced
delivery of oxygen result in increased
anaerobic metabolism and the production of
lactic acid.
– The respiratory system attempts to compensate
for the acidosis by increasing ventilation to blow
off carbon dioxide.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Stage 2: Capillary and Venule
Opening (5 of 5)
As acidosis increases and pH falls, the RBCs may
cluster together (rouleaux formation).
– Halts perfusion
– Affects nutritional flow and prevents removal of cellular
metabolites
Clotting mechanisms are also affected, leading to
hypercoagulability.
This stage of shock often progresses to the third
stage if fluid resuscitation is inadequate or delayed,
or if the shock state is complicated by trauma or
sepsis.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Stage 3: Disseminated
Intravascular Coagulation (DIC)
(1 of 4)
Time of onset will depend on degree of
shock, patient age, and pre-existing medical
conditions.
Stage 3 occurs with 25% to 35% decrease
in intravascular blood volume. At this stage,
hypotension occurs. This stage of shock
usually requires blood replacement.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Stage 3: Disseminated
Intravascular Coagulation (DIC)
(2 of 4)
Stage 3 is resistant to treatment (refractory
shock), but is still reversible.
Blood begins to coagulate in the
microcirculation, clogging capillaries.
– Capillaries become occluded by clumps of
RBCs.
Decreases capillary perfusion and prevents removal of
metabolites
– Distal tissue cells use anaerobic metabolism,
and lactic acid production increases.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Stage 3: Disseminated
Intravascular Coagulation (DIC)
(3 of 4)
Lactic acid accumulates around the
cell.
– Cell membranes no longer have the
energy needed to maintain homeostasis.
– Water and sodium leak in, potassium
leaks out, and the cells swell and die.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Stage 3: Disseminated
Intravascular Coagulation (DIC)
(4 of 4)
Pulmonary capillaries become permeable,
leading to pulmonary edema.
– Decreases the absorption of oxygen and results
in possible alterations in carbon dioxide
elimination
– May lead to acute respiratory failure or adult
respiratory distress syndrome (ARDS)
If shock and disseminated intravascular
coagulation (DIC) continue, the patient
progresses to multiple organ failure.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Stage 4: Multiple Organ Failure
(1 of 2)
The amount of cellular necrosis required to
produce organ failure varies with each
organ and the underlying condition of the
organ.
– Usually hepatic failure occurs, followed by renal
failure, and then heart failure.
– If capillary occlusion persists for more than 1 to
2 hours, the cells nourished by that capillary
undergo changes that rapidly become
irreversible.
In this stage, blood pressure falls
dramatically (to levels of 60 mmHg or less).
– Cells can no longer use oxygen, and
metabolism stops.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Stage 4: Multiple Organ Failure
(2 of 2)
If a critical amount of the vital organ is
damaged by cellular necrosis, the organ
soon fails.
– Failure of the liver is common and often
presents early.
– Capillary blockage may cause heart failure.
– GI bleeding and sepsis may result from GI
mucosal necrosis.
– Pancreatic necrosis may lead to further clotting
disorders and severe pancreatitis.
Pulmonary thrombosis may produce
hemorrhage and fluid loss into the alveoli.
– Leading to death from respiratory failure.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Shock and Hemorrhage
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Defining Shock (1 of 2)
Shock is best defined as inadequate
tissue perfusion.
– Can result from a variety of disease
states and injuries.
– Can affect the entire organism, or it can
occur at a tissue or cellular level.
“The rude unhinging of the machinery of Life”
Gross, 1877
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Defining Shock (2 of 2)
Shock is not adequately defined by:
–
–
–
–
–
Pulse rate
Blood pressure
Cardiac function
Hypovolemia
Loss of systemic vascular resistance
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Hemorrhage Classification
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
External Hemorrhage
Results from soft tissue injury.
Accounts for nearly 10 million emergency
department visits in the United States each year.
Most soft tissue trauma is accompanied by mild
hemorrhage and is not life threatening.
– Can carry significant risks of patient morbidity and
disfigurement
The seriousness of the injury is dependent on:
–
–
–
Anatomical source of the hemorrhage (arterial, venous,
capillary)
Degree of vascular disruption
Amount of blood loss that can be tolerated by the patient
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Internal Hemorrhage (1 of 2)
Can result from:
– Blunt or penetrating trauma
– Acute or chronic medical illnesses
Internal bleeding that can cause
hemodynamic instability usually occurs in
one of four body cavities:
–
–
–
–
Chest
Abdomen
Pelvis
Retroperitoneum
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Internal Hemorrhage (2 of 2)
Signs and symptoms that may suggest
significant internal hemorrhage include:
– Bright red blood from mouth, rectum, or
other orifice
– Coffee-ground appearance of vomitus
– Melena (black, tarry stools)
– Dizziness or syncope on sitting or
standing
– Orthostatic hypotension
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Internal hemorrhage is
associated with higher morbidity
and mortality than external
hemorrhage.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Physiological Response to
Hemorrhage
The body’s initial response to
hemorrhage is to stop bleeding by
chemical means (hemostasis).
– This vascular reaction involves:
Local vasoconstriction
Formation of a platelet plug
Coagulation
Growth of tissue into the blood clot that
permanently closes and seals the injured
vessel
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Fick Principle
A method for measuring cardiac output.
The Fick principle assumes that the quantity
of oxygen delivered to an organ is equal to
the amount of oxygen consumed by that
organ plus the amount of oxygen carried
away from that organ.
Used to estimate perfusion either to an
organ or to the whole body when oxygen
content of both the arterial and venous
blood is known and oxygen consumption is
assumed to remain fixed.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Hemorrhage Control
External Hemorrhage
– Direct pressure and pressure dressing
– General management
Direct pressure
Elevation
Ice
Pressure points
Constricting band
Tourniquet
May use a BP cuff by inflating the cuff 20–30 mmHg
above the SBP
Release may send toxins to heart
Lactic acid and electrolytes
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Tourniquets are ONLY used
as a last resort!
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Internal Hemorrhage Control
Hematoma
– Epistaxis: Nose Bleed
Causes: trauma,
hypertension
Treatment: lean
forward, pinch nostrils
– Pocket of blood
between muscle and
fascia
UNEXPLAINED
SHOCK is BEST
attributed to abdominal
trauma
General Management
– Immobilization,
stabilization, elevation
–
–
–
–
–
Hemoptysis
Esophageal Varices
Melena
Diverticulosis
Chronic Hemorrhage
Anemia
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Stages of Hemorrhage
60% of body weight is fluid.
– 7% circulating blood volume (CBV) in
men
5 L (10 units)
– 6.5% CBV in women
4.6 L (9–10 units)
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Stages of Hemorrhage
Stage 1
15% loss of CBV
– 70 kg pt = 500–750 mL
Compensation
–
–
–
–
Vasoconstriction
Normal BP, pulse pressure, respirations
Slight elevation of pulse
Release of catecholamines
Epinephrine
Norepinephrine
Anxiety, slightly pale and clammy skin
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Stages of Hemorrhage
Stage 2 (1 of 2)
15–25% loss of CBV
– 750–1250 mL
Early decompensation
– Unable to maintain BP
– Tachycardia and tachypnea
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Stages of Hemorrhage
Stage 2 (2 of 2)
Decreased pulse strength
Narrowing pulse pressure
Significant catecholamine release
–
–
–
–
Increase PVR
Cool, clammy skin and thirst
Increased anxiety and agitation
Normal renal output
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Stages of Hemorrhage
Stage 3 (1 of 2)
25–35% loss of CBV
– 1250–1750 mL
Late decompensation (early
irreversible)
– Compensatory mechanisms unable to
cope with loss of blood volume
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Stages of Hemorrhage
Stage 3 (2 of 2)
Classic Shock
– Weak, thready, rapid pulse
Narrowing pulse pressure
–
–
–
–
Tachypnea
Anxiety, restlessness
Decreased LOC and AMS
Pale, cool, and clammy skin
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Stages of Hemorrhage
Stage 4
>35% CBV loss
– >1750 mL
Irreversible
–
–
–
–
–
–
Pulse: Barely palpable
Respiration: Rapid, shallow, and ineffective
LOC: Lethargic, confused, unresponsive
GU: Ceases
Skin: Cool, clammy, and very pale
Unlikely survival
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Stages of Hemorrhage
Concomitant Factors (1 of 2)
Pre-existing condition
Rate of blood loss
Patient Types
– Pregnant
>50% greater blood volume than normal
Fetal circulation impaired when mother compensating
– Athletes
Greater fluid and cardiac capacity
– Obese
CBV is based on IDEAL weight (less CBV)
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Stages of Hemorrhage
Concomitant Factors (2 of 2)
Children
– CBV 8–9% of body weight
– Poor compensatory mechanisms
– TREAT AGGRESSIVELY!
Elderly
– Decreased CBV
– Medications
BP
Anticoagulants
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Hemorrhage Assessment (1 of 5)
Scene Size-up
– Is it safe?
BSI
– Blood loss
Law enforcement
– Mechanism of Injury/Nature of Illness
Should only be used in conjunction with vital
signs and other clinical signs of injury to
determine the probability of injury
– Number of Patients
– Need for Additional Resources
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Hemorrhage Assessment (2 of 5)
Initial Assessment
– General Impression
Obvious bleeding
– Mental Status
– CABC
– Interventions
Manage as you go
O2
Bleeding control
Shock
BLS before ALS!
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Hemorrhage Assessment (3 of 5)
Focused H&P
– Rapid Trauma Assessment
Full head to toe
Consider air medical if stage 2+ blood loss
– Focused Physical Exam
Guided by c/c
– Vitals, SAMPLE, and OPQRST
– Additional Assessment
Orthostatic hypotension
Tilt test: 20
BP or P from supine to sitting
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Hemorrhage Assessment (4 of 5)
Fractures and Blood Loss
Pelvic fracture:
Femur fracture:
Tibia/fibula fracture:
Hematomas and contusions:
2,000 mL
1,500 mL
500–750 mL
500 mL
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Hemorrhage Assessment (5 of 5)
Ongoing Assessment
– Reassess vitals and mental status:
Q 5 min: UNSTABLE patients
Q 15 min: STABLE patients
– Reassess interventions:
Oxygen
ET
IV
Medication actions
– Trending: improvement vs. deterioration
Pulse oximetry
End-tidal CO2 levels
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
SHOCK is…
INADEQUATE TISSUE
PERFUSION.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Shock Management
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Specific Wound Considerations
(1 of 2)
Head Wounds
Neck Wounds
– Presentation
– Presentation
Severe bleeding
Skull fracture
– Management
Gentle direct
pressure
Fluid drainage from
ears and nose
Large vessel can
entrap air
– Management
Consider direct
digital pressure
Occlusive dressing
DO NOT pack
Cover and
bandage loosely
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Specific Wound Considerations
(2 of 2)
Gaping Wounds
– Presentation
Multiple sites
Gaping prevents
uniform pressure
– Management
Bulky dressing
Trauma dressing
Sterile, nonadherent surface to
wound
Compression
dressing
Crush Injury
– Presentation
Difficult to locate
source of bleeding
Normal hemorrhage
control mechanism
nonfunctional
– Management
Consider an airsplint and pressure
dressing
Consider tourniquet
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Transport Considerations
Consider rapid transport:
– Suspected serious blood loss
– Suspected serious internal bleeding
– Decompensating shock
AMS, pulse, narrowing pulse pressure
– WHEN IN DOUBT, TRANSPORT.
Other Considerations
– Sympathetic response
– Anxiety
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Shock Management (1 of 2)
Airway and Breathing
–
–
–
–
–
NRB
PPV (overdrive respiration)
ET
CPAP
PEEP
Hemorrhage Control
Fluid Resuscitation
–
–
–
–
–
Any injury to the
head or torso is
ALSO considered an
injury to the spine.
Catheter size and length
Large bore
20 mL/kg of NS or LR
Polyhemoglobins
STABILIZE VITALS to SBP of 80 mmHg or 90 mmHg in head
injuries.
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Shock Management (2 of 2)
Temperature Control
– Conserve core temperature
– Warm IV fluids
PASG
– Action
Increase PVR
Reduce vascular volume
Increase central CBV
Immobilize lower extremities
– Assess
Pulmonary edema
Pregnancy
Vital signs
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Summary
Introduction to Hemorrhage and Shock
Hemorrhage
Shock
Bledsoe et al., Essentials of Paramedic Care: Division 1II
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ