Ch07 shock

Emergency Care
CHAPTER
Copyright © 2016, 2012, 2009 by Pearson Education, Inc.
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Emergency Care, 13e
Daniel Limmer | Michael F. O'Keefe
THIRTEENTH EDITION
Ventilation, Perfusion,
and Shock:
Understanding
Pathophysiology
7

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Emergency Care, 13e
Multimedia Directory
Slide 15 Cell Structure Video
Slide 47 Transport of Carbon Dioxide Animation

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Topics
• The Cell
• The Cardiopulmonary System
• Shock
• Pathophysiology of Other Systems

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Introduction to Pathophysiology
• Study of how disease processes affect
function of body
• Understanding helps you recognize
changes patient is going through due to
illness or injury

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The Cell

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The Cell
• Cell membrane protects and selectively
allows water and other substances in
and out of the cell
• Mitochondria convert glucose and other
nutrients into adenosine triphosphate
(ATP).
 Fuel for cell functions
 Without ATP, many of the cell's
specialized structures cannot function.

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The Cell
The cell.

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Water and the Cell
• Cells need the correct balance of water
inside and outside.
 Too little water
• Cell dehydrated and dies
 Too much water
• Basic cellular function interrupted
• Water also affects levels of electrolytes.
 Impacts electrical functions

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Think About It
• Draw an analogy between cell
metabolism and how a refinery turns
crude oil into gasoline for use in
automobiles.

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Glucose and the Cell
• Building block for energy
• Supply of insulin must match the
body's glucose requirement.

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Oxygen and the Cell
• Aerobic metabolism
 Cellular functions using oxygen
• Anaerobic metabolism
 Cellular functions not using oxygen
• Creates much less energy and much
more waste
• Body becomes acidic, impairing many
body functions.

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Oxygen and the Cell
Aerobic metabolism. Glucose broken down in the presence of oxygen produces a
large amount of energy (ATP).

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Oxygen and the Cell
Anaerobic metabolism. Glucose broken down without the presence of oxygen
produces acidic by-products and only a small amount of energy (ATP).

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The Vulnerability of Cells, Organs,
and Organ Systems
• Many diseases alter the permeability of
membrane.
• Ineffective cell membrane can allow
substances into the cell that should not
be there.
• These substances can interfere with the
regulation of water.

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Cell Structure Video
Click on the screenshot to view a video on the topic of cell structure.
Back to Directory

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The Cardiopulmonary System

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The Cardiopulmonary System
• Respiratory and cardiovascular systems
work together.
 Bring oxygen into body
 Distribute to cells
 Remove waste products
• Any breakdown can result in system
failure.

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The Airway
The bronchial tree. Each mainstem bronchus enters a lung then branches into smaller
and smaller bronchi, ending in the smallest bronchioles.

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The Airway
(A) Each bronchiole terminates in a tiny air pocket called an alveolar sac. (B) The
alveoli are encased by networks of capillaries; oxygen and carbon dioxide are
exchanged between the air in the alveoli and the blood in the capillaries.

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The Airway
• Must have an open (patent) airway for
system to function
• Upper airway obstructions are common.
 Caused by foreign bodies, infection, or
trauma

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The Lungs
• Part of lower airway
• Tidal volume
 Volume of air moving in and out during
each breath cycle
• Tidal volume × respiratory rate =
minute volume
 Amount of air moved in and out of lungs
in one minute
continued on next slide

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The Lungs
• Any change in tidal volume or
respiratory rate reduces minute
volume.
• Respiratory dysfunction occurs any
time something interferes with minute
volume.

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Respiratory Dysfunction
• Disruption of respiratory control
 Respirations controlled in brain by the
medulla oblongata
 Any event impacting function of the
medulla oblongata can affect minute
volume
• Infection, drugs, toxins, trauma

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• Disruption of pressure
 If wall of thorax is compromised
(punctures, rib fractures), ability to
inhale and exhale is impacted and
minute volume is reduced.
 Air or blood accumulating in chest
(pleural space) also compromises
respiration.

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• Disruption of lung tissue
 Trauma or medical problems can
compromise the ability of alveoli to
exchange gases.
 Less oxygen gets in; less carbon dioxide
gets out.
 Can result in low oxygen levels
(hypoxia) and high carbon dioxide levels
(hypercapnia)

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Respiratory Compensation
• Body attempts to compensate for gas exchange
deficits.
• Chemoreceptors detect changing oxygen and carbon
dioxide levels.
• Brain stimulates respiratory system to increase rate
and/or tidal volume.

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The Blood
• Four parts
 Plasma (liquid)
 Red blood cells
• Contain oxygen-carrying hemoglobin
 White blood cells
• Fight infection
 Platelets
• Form clots

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The Blood
• Plasma oncotic pressure
 Proteins in plasma attract water away
from are around cells and pulls it into
bloodstream.
• Hydrostatic pressure
 Water pushed back out of blood vessels
towards cells.
• Problems with these proteins can cause
an imbalance.

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Blood Dysfunction
• Without enough blood, oxygen and
carbon dioxide cannot be properly
moved around.
 Bleeding
 Dehydration
 Anemia
 Liver failure

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The Blood Vessels
The network of arteries, veins, and capillaries.

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The Blood Vessels
• Take oxygenated blood from lungs via
heart to capillaries
• Where gas exchange takes place
 Between cells and capillaries
• Return blood to lungs via heart for gas
exchange
 Between capillaries and alveoli

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The Blood Vessels
• Need adequate pressure to make cycle
work
• Pressure controlled by changing
diameter of blood vessels
• Stretch receptors monitor pressure.
• Pressure can be increased or decreased
depending on situation.

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Blood Vessel Dysfunction
• Loss of Tone
 Vessels lose ability to constrict and
dilate.
 Pressure drops
 Causes
• Trauma
• Infection
• Allergic reaction

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Dilated blood vessel.

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• Excessive permeability
 Capillaries leak fluid out their walls.
 Caused by severe infection (sepsis),
high altitude, and certain diseases

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Increased permeability allows too much fluid to escape through capillary walls.

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• Hypertension
 Systemic vascular resistance (SVR)
 Pressure inside vessels
 Various conditions lead to abnormal
constriction of vessels, leading to
dangerously high pressures
(hypertension).
 Major risk factor in stroke and heart
disease

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The Heart
• Pump with average stroke volume
(output) of about 70 mL blood per
contraction

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The Heart
• Stroke volume is based on:
 Preload
• Amount of blood returning to heart
 Contractility
• How hard heart squeezes
 Afterload
• Pressure the heart has to pump against
to force blood out into the system

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Cardiac Output
• Stroke volume × beats per minute =
cardiac output
• Slowing heart rate or decreasing stroke
volume reduces cardiac output.
• Very fast heart rates reduce cardiac
output.
 Inadequate time for heart to refill
between contractions

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Heart Dysfunction
• Mechanical problems
 Physical trauma
 Squeezing forces
 Cell death (heart attack)
• Electrical problems
 Damage to heart's ability to regulate
rate

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The Cardiopulmonary System:
Putting It All Together
• Entire cardiopulmonary system must
work together to maintain life.
• Must be a balance between ventilation
(V) and perfusion (Q) for system to
work properly
 V/Q match
• Any breakdown in system impacts ratio
causing possible life-threatening
situation.

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Shock

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Shock
• Perfusion
 Regular delivery of oxygen and
nutrients to cells and removal of waste
products
• Hypoperfusion
 Breakdown in system
• Can result in death of patient

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Four Categories of Shock
• Hypovolemic
• Distributive
• Cardiogenic
• Obstructive

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Recognizing Compensation
• When problems arise, body attempts to
compensate.
• Signs of compensated shock
 Slight mental status changes
 Increased heart rate
 Increased respiratory rate
 Delayed capillary refill time
 Pale, cool, clammy skin
 Sweating

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Transport of
Carbon Dioxide Animation
Click on the screenshot to view an animation on the subject of the transport of
carbon dioxide.
Back to Directory

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Pathophysiology of Other
Systems

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Fluid Balance
• Body is 60 percent water.
 Intracellular (70 percent)
 Intravascular (5 percent)
 Interstitial (25 percent)

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Fluid Balance
Water comprises approximately 60 percent of body weight. The water is distributed
into three spaces: intracellular, intravascular, and interstitial.

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Fluid Balance
• Brain and kidneys regulate thirst and
elimination of excess fluid
• Blood plasma proteins pull fluid into the
bloodstream
• Cell membrane and capillary
permeability regulate flow in and out

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Disruptions of Fluid Balance
• Fluid loss (dehydration)
 Decrease in total water volume
• Poor fluid distribution
 Water not getting to where it needs to
go
 Edema
• Too much water in some parts of the
body

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The Nervous System
• Brain and spinal cord are well-protected
by skull and spine.
 Covered by several protective layers
(meninges) and a layer of shock-
absorbing fluid (cerebrospinal fluid)
 Still subject to damage from trauma or
disease

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Emergency Care, 13e
Nervous System Dysfunction
• Medical dysfunction
 Strokes
 Infection (meningitis, encephalitis)
 Disease (Lou Gehrig disease, MS)
 Low blood sugar (hypoglycemia)

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Emergency Care, 13e
Endocrine System Dysfunction
• Organ or gland problems
• Present at birth or result of illness
• Too many hormones
 Graves' disease (too much thyroid
hormone)
 Problems with heart rate and
temperature regulation
• Not enough hormones
 Diabetes

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Digestive Dysfunction
• Impacts hydration levels and nutrient
transfer
• Gastrointestinal bleeding
 Can be slow
• Chronic bleeding
 Can be massive, with rectal bleeding
and/or vomiting blood

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Emergency Care, 13e
Hypersensitivity (Allergic Reaction)
• Allergic reaction to certain food, drugs,
other substances
• Result of exaggerated immune
response
• Chemicals affect more than just
invader.

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Chapter Review
• Pathophysiology allows us to
understand how negative forces impact
the normal function of the body.
• Pathophysiology helps us understand
how common disorders cause changes
in the body.

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Chapter Review
• Understanding how the body
compensates for insults sheds light on
the signs and symptoms we may see
during assessment.
• Understanding what compensation
looks like helps us rapidly identify
potentially life-threatening problems.

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Emergency Care, 13e
Remember
• Cellular metabolism requires a constant
supply of oxygen and glucose. Absence
of either component disrupts normal
metabolism.
• Cardiopulmonary system combines the
functions of respiratory and
cardiovascular systems to provide
oxygen at the cellular level.

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Emergency Care, 13e
Remember
• Shock occurs when the
cardiopulmonary system fails and cells
become hypoperfused.
• The body is composed primarily of
water, and this fluid is distributed
throughout the body systems.

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Emergency Care, 13e
Questions to Consider
• When evaluating a patient with a
cardiac problem, consider the impact
on the respiratory system. When
evaluating a patient with a respiratory
problem, consider the impact on the
cardiovascular system. What impacts
do problems in these systems have on
each other?

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Emergency Care, 13e
Critical Thinking
• You are treating a patient who was
recently released from the intensive
care unit with a massive infection
(sepsis). This has impaired the patient's
ability to regulate the size of the blood
vessels.

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Emergency Care, 13e
Critical Thinking
• How might this affect the patient's
ability to compensate for any additional
illnesses? What steps should you take
to help this patient compensate?

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