Download Chapter 08

MASTER TEACHING NOTES
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Detailed Lesson Plan
Chapter 8
Pathophysiology
165–180 minutes
Case Study Discussion
Teaching Tips
Discussion Questions
Class Activities
Media Links
Knowledge Application
Critical Thinking Discussion
Chapter 8 objectives can be found in an accompanying folder.
These objectives, which form the basis of each chapter, were developed from the new Education Standards and Instructional Guidelines.
Minutes
Content Outline
I.
5
25
20
Master Teaching Notes
Introduction
Case Study Discussion
A. During this lesson, students will learn about processes that occur in the
human body.
B. Case Study
1. Present The Dispatch and Upon Arrival information from the chapter.
2. Discuss with students how they would proceed.
II. Cellular Metabolism—Aerobic Metabolism
A. Cellular metabolism, or cellular respiration, is the process through which
cells break down glucose to produce energy for the body.
B. Aerobic respiration is cellular respiration in the presence of oxygen.
C. Glycolysis is the process through which glucose is broken down into pyruvic
acid molecules.
1. Occurs in the cytosol
2. Releases only a small amount of energy (two moles of ATP)
D. The process continues in the mitochondria in the presence of oxygen to
release a much large amount of energy (36 moles of ATP).
E. By-products include heat, carbon dioxide, and water.
III. Cellular Metabolism—Anaerobic Metabolism
A. Anaerobic metabolism is cellular respiration in the absence of oxygen.
1. As in aerobic respiration, glucose is converted to pyruvic acid in the
cytosol.
2. Without oxygen, the pyruvic acid is converted into lactic acid.
3. By-products are lactic acid and two moles of ATP.
4. High levels of acid inactivate enzyme function, disrupt cell membranes,
and lead to cell death.
B. Sodium/potassium pump failure
PREHOSPITAL EMERGENCY CARE, 9TH EDITION
DETAILED LESSON PLAN 8
How does the patient’s loss of blood
place his life in jeopardy?
 What actions can you take to address
the patient’s immediate threats to life?

Discussion Question
Why do all cells of the body need oxygen?
Animation
Go to www.bradybooks.com
and click on the mykit link for Prehospital
Emergency Care, 9th edition to access an
animation describing cellular structures and
respiration.
Critical Thinking Discussion
What are some reasons why cells might not
receive the glucose they need for
metabolism?
Discussion Questions

What are the consequences of
inadequate oxygenation of the body’s
PAGE 1
Chapter 8 objectives can be found in an accompanying folder.
These objectives, which form the basis of each chapter, were developed from the new Education Standards and Instructional Guidelines.
Minutes
Content Outline
Master Teaching Notes

tissues?
What causes cells to swell and burst if
hypoxia continues?
IV. Components Necessary for Adequate Perfusion—Composition of
15
Ambient Air
A. Perfusion is the delivery of oxygen, glucose, and other substances to the
cells and the elimination of waste products from the cells.
B. The concentration of oxygen in ambient air will determine the proportion of
oxygen molecules that end up in the alveoli to be available for gas exchange
with the blood.
1. The concentration of oxygen the patient is breathing should be at least
21 percent.
2. If the concentration is lower, less oxygen will be available for cells to use
for metabolism.
C. One way to improve cellular oxygenation is by increasing the concentration
of oxygen in the air breathed in by the patient.
1. FiO2 is the fraction of inspired oxygen administered to a patient who is
breathing on his own.
2. FDO2 is a fraction of delivered oxygen delivered by a ventilation device
to a patient who is not able to breathe on his own.
D. Toxic gases
1. Some toxic gases displace the amount of oxygen in the air and
suffocate the patient.
2. Some gases disrupt the ability of the blood to carry adequate amounts
of oxygen to the cells.
3. Some toxic gases may interfere with the ability of the cells to use
oxygen.
PREHOSPITAL EMERGENCY CARE, 9TH EDITION
DETAILED LESSON PLAN 8
Critical Thinking Discussion
What are some reasons why cells might not
receive an adequate amount of oxygen?
PAGE 2
Chapter 8 objectives can be found in an accompanying folder.
These objectives, which form the basis of each chapter, were developed from the new Education Standards and Instructional Guidelines.
Minutes
10
Content Outline
Master Teaching Notes
V. Components Necessary for Adequate Perfusion—Patency of Airway
A. A patent airway is one that is not obstructed.
B. Nasopharynx
1. Blood, vomitus, or other substances that occlude the nasopharynx may
drain into the pharynx and lead to aspiration or occlusion.
2. The nasopharynx must be kept clear in case it needs to be used as an
alternative location to establish an airway.
C. Oropharynx and pharynx
1. Can become obstructed by the tongue, foreign bodies, tissue swelling,
hematomas, vomitus, and other substances
2. Obstructions must be removed immediately because aspirated
substances can damage lung tissue or fill the alveoli, thereby interfering
with gas exchange.
D. Epiglottis
1. The flap of cartilaginous tissue that covers the opening of the larynx
2. Can become inflamed and occlude the airway
E. Larynx
1. The structure that contains the vocal cords
2. Obstructions will prevent airflow into the trachea and lungs, resulting in
poor oxygen levels in the blood and cellular hypoxia.
a. Can be obstructed by laryngeal spasm, where the vocal cords
spasm and close together
b. Fracture of the larynx may cause the laryngeal structures to be
drawn inward.
F. Trachea and bronchi
1. Trachea extends downward and bifurcates at the carina.
2. Trachea bifurcates into the left and right bronchi.
3. Obstructions of the trachea or bronchi reduce the concentration of
oxygen in the alveoli, leading to cellular hypoxia.
PREHOSPITAL EMERGENCY CARE, 9TH EDITION
DETAILED LESSON PLAN 8
PAGE 3
VI. Components Necessary for Adequate Perfusion—Respiratory
10
Compromise Associated with Mechanics of Ventilation
A. Boyle’s Law applied to ventilation
1. An increase in pressure will decrease the volume of gas.
2. A decrease in pressure will increase the volume of gas.
B. Accessory Muscles
1. Accessory muscles may be required to increase chest size or force air
out of the lungs and chest.
a. Inhalation involves sternocleidomastoid muscles, scalene muscles,
and pectoralis minor muscles.
b. Exhalation involves abdominal muscles and internal intercoastal
muscles.
C. Compliance and airway resistance
1. Compliance is a measure of the ability of the chest wall and lungs to
stretch, distend, and expand.
2. Airway resistance relates to the ease of airflow down the conduit of
airway structures leading to the alveoli.
D. Pleural space
1. Any break in the pleura creates negative pressure, which draws air into
the pleural space.
2. Occluding any open wound to the chest must be done early in the
primary assessment of a patient.
E. Minute ventilation is the amount of air moved in and out of the lungs in one
minute.
1. Determined by multiplying the tidal volume by the frequency of
ventilation in one minute
2. Tidal volume is the volume of air breathed in with each individual breath.
3. Frequency of ventilation is the number of ventilations in one minute.
a. A decrease in tidal volume or frequency of ventilation will decrease
the minute ventilation.
b. A decrease in the minute ventilation will reduce the amount of air
available for gas exchange in the alveoli and lead to cellular
hypoxia.
F. Alveolar ventilation
1. Alveolar ventilation is the amount of air moved in and out of the alveoli in
one minute.
2. Dead air space (VD) consists of anatomical areas in the respiratory tract
where air collects during inhalation.
PREHOSPITAL EMERGENCY CARE, 9TH EDITION
DETAILED LESSON PLAN 8
Discussion Questions
 How do patients compensate for a
condition that decreases tidal volume?
 If a patient’s tidal volume is 300 mL and
his respiratory rate is 20, what is the
alveolar ventilation? Is this adequate or
not?
Critical Thinking Discussion
Will applying oxygen by nonrebreather
mask improve tidal volume? Why or why
not?
Teaching Tip
Give several examples of how changing the
tidal volume and respiratory rate change
the minute volume.
Knowledge Application
Given several scenarios including a
patient’s respiratory rate and tidal volume,
determine if the patient’s alveolar ventilation
is likely to be adequate or inadequate.
Teaching Tip
Ask students to breathe normally through a
drinking straw to demonstrate the effect of
dead air space on alveolar ventilation.
PAGE 4
VII. Components Necessary for Adequate Perfusion—Regulation of
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Ventilation
A. Chemoreceptors monitor pH, carbon dioxide, and oxygen levels in arterial
blood.
1. Central chemoreceptors are most sensitive to carbon dioxide and
changes in the pH of the cerebrospinal fluid (CSF).
2. Peripheral chemoreceptors are most sensitive to the level of oxygen in
the arterial blood.
3. Hypoxic drive is a condition in which hypoxia becomes the stimulus for
ventilation in place of hypercarbia.
B. Lung receptors provide impulses to regulate respiration.
1. Irritant receptors
2. Stretch receptors
3. J-receptors
C. Respiratory centers in the brain stem
1. Dorsal respiratory group (DRG)
2. Ventral respiratory group (VRG)
3. Apneustic center
4. Pneumotaxic center
Discussion Question
How can an injury to the brain interfere with
perfusion?
VIII. Components Necessary for Adequate Perfusion—Ventilation/
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Perfusion Ratio
A. The ventilation/perfusion (V/Q) ratio relates the amount of ventilation the
alveoli receive to the amount of perfusion through the capillaries
surrounding the alveoli.
1. In the apexes of the lungs, the amount of available ventilation in the
alveoli exceeds the amount of perfusion through the pulmonary
capillaries.
2. In the bases of the lungs, the amount of perfusion exceeds the amount
of ventilation.
B. Pressure imbalances
1. If the pressure in an alveolus exceeds the blood pressure in the capillary
bed, blood flow through the capillary stops.
2. Pressure imbalance will result in poor pulmonary perfusion, hypoxemia,
and cellular hypoxia.
C. Ventilatory disturbances
1. If less oxygenated air is available in the alveoli for the amount of blood
flowing through the pulmonary capillaries, less oxygen will be delivered
to the cells.
2. Ventilatory disturbances can lead to hypoxemia and cellular hypoxia.
3. Managing such a disturbance should focus on improving ventilation and
PREHOSPITAL EMERGENCY CARE, 9TH EDITION
DETAILED LESSON PLAN 8
Discussion Question
What is the concept of the
ventilation/perfusion ratio?
Critical Thinking Discussion
A patient takes a drug that prevents the
heart rate from increasing. What are the
consequences if the patient lost a large
quantity of blood?
PAGE 5
oxygenation.
D. Perfusion disturbances
1. If adequate oxygenated air is moving into the alveoli, but there is not
enough blood to pick it up due to decreased blood flow, less oxygen will
be delivered to the cells.
2. A perfusion disturbance can lead to severe cellular hypoxia.
3. Managing such a disturbance should focus on increasing blood flow
through the pulmonary capillaries, the availability of hemoglobin, and the
delivery of oxygen to the cells.
15
IX. Components Necessary for Adequate Perfusion—Transport of
Oxygen and Carbon Dioxide by the Blood
A. A disturbance in the transport system may lead to cellular hypoxia and
hypercarbia.
1. Cellular hypoxia is a lack of oxygen available to the cells.
2. Hypercarbia is a buildup of carbon dioxide in the blood.
B. Oxygen transport
1. About 1.5 to 3 percent of oxygen is dissolved in plasma.
2. About 97 to 98.5 percent of oxygen is transported by attaching to
hemoglobin molecules.
3. Hemoglobin is a protein molecule that has four iron sites for oxygen to
bind to.
4. Oxyhemoglobin describes an oxygen molecule once it binds with
hemoglobin.
5. Deoxyhemoglobin describes a hemoglobin molecule without any oxygen
attached to it.
C. Carbon dioxide transport
1. About 7 percent of carbon dioxide is dissolved in plasma.
2. About 23 percent of carbon dioxide is attached to hemoglobin.
3. About 70 percent of carbon dioxide is in the form of bicarbonate.
D. Alveolar/capillary gas exchange
1. Gases move from areas of higher concentration to areas of lower
concentration.
2. Oxygen moves from alveoli into capillaries while carbon dioxide moves
from capillaries into alveoli.
3. Carbon-dioxide rich air is then expelled during exhalation while oxygen
is carried to the left atrium of the heart to the left ventricle and then
throughout the body.
E. Cell/capillary gas exchange
1. Oxygen-rich blood from the left ventricle travels through an artery to
PREHOSPITAL EMERGENCY CARE, 9TH EDITION
DETAILED LESSON PLAN 8
Critical Thinking Discussion
A blood clot obstructs blood flow through
the pulmonary artery. Explain how this
affects perfusion.
Class Activity
Perfusion biographies. Assign students to
play the role of various components of
perfusion (red blood cells, right ventricle,
and so on). Encourage students to select a
name for their component, such as Larry
the Left Ventricle. Students will spend five
to ten minutes writing the biography of their
component and will then present it to the
class.
Animations
Go to www.bradybooks.com
and click on the mykit link for Prehospital
PAGE 6
arterioles to capillaries.
2. In the capillaries, oxygen breaks free of hemoglobin and diffuses out of
the plasma and into the cell.
3. In the capillaries, carbon dioxide leaves the cell and crosses over into
the capillary where it dissolves, attaches to hemoglobin, or is converted
to bicarbonate.
4. Blood rich in carbon dioxide is then transported back to the right atrium
of the heart, to the right ventricle, and then pumped to the lungs.
Emergency Care, 9th edition to access
animations describing the transport of
carbon dioxide in the human body and the
process of gas exchange.
X. Components Necessary for Adequate Perfusion—Blood Volume
15
A. Composition of blood
1. About 45 percent of blood composition is made up of cells and proteins.
2. About 55 percent of blood composition is made up of plasma.
B. Plasma suspends and carries the formed elements in blood.
1. About 91 percent of plasma consists of water.
2. Much of the remaining portion of plasma consists of proteins.
a. Albumin plays a major role in maintaining the fluid balance in blood.
b. Antibodies are responsible for the defense against infectious
organisms.
c. Clotting factors, such as fibrinogen, are key in coagulation of blood
from damaged vessels.
C. Formed elements include red blood cells, white blood cells, and platelets.
a. Red blood cells, which contain hemoglobin, are responsible for
carrying oxygen and delivering it to cells.
b. White blood cells protect the body against infection and eliminate
dead and injured cells.
c. Platelets are cell fragments that play a role in clotting.
D. Distribution of blood
a. Most blood is housed within the venous system.
b. The venous system changes size to respond to changes in blood
volume.
c. The venous system supplies the right side of the heart with an
adequate volume of blood.
E. Hydrostatic pressure
a. Hydrostatic pressure is the force inside the vessel or capillary bed
generated by the contraction of the heart and blood pressure.
b. A high hydrostatic pressure forces more fluid out of the vessel or
capillary, thereby promoting edema.
F. Plasma oncotic pressure
a. Plasma oncotic pressure is responsible for keeping fluid inside the
vessels.
PREHOSPITAL EMERGENCY CARE, 9TH EDITION
DETAILED LESSON PLAN 8
Weblink
Go to www.bradybooks.com
and click on the mykit link for Prehospital
Emergency Care, 9th edition to access a
web resource describing the composition of
blood.
Animation
Go to www.bradybooks.com
and click on the mykit link for Prehospital
Emergency Care, 9th edition to access an
animation showing changes in pressure
described by Starling’s Law.
Weblink
PAGE 7
b. This pressure, generated by large plasma proteins, acts opposite to
hydrostatic pressure.
c. A balance between hydrostatic pressure and plasma oncotic
pressure must be maintained for equilibrium of fluid balance.
10
XI. Components Necessary for Adequate Perfusion—Pump Function of
the Myocardium
A. Cardiac output
1. Cardiac output is the amount of blood ejected by the left ventricle in one
minute.
2. Cardiac output equals the heart rate times the stroke volume.
B. Heart rate
1. The heart rate is the number of times the heart contracts in one minute.
2. The heart rate is influenced by the sinoatrial (SA) node along with
hormones and the automatic nervous system.
3. The sympathetic and parasympathetic nervous systems exert control
through the cardiovascular control center in the brain stem.
a. An increase in stimulation by the sympathetic nervous system or a
decrease in stimulation by the parasympathetic nervous system
increases heart rate.
b. An increase in stimulation by the parasympathetic nervous system
or a decrease in stimulation by the sympathetic nervous system
decreases heart rate.
C. Stroke volume
1. Stroke volume is the volume of blood ejected by the left ventricle with
each contraction.
2. Preload is the pressure generated in the left ventricle at the end of
diastole.
3. Frank Starling’s law of the heart describes that the stretch of the muscle
fiber at the end of diastole determines the force available to eject the
blood from the ventricle.
4. Afterload is the resistance in the aorta that must be overcome by
contraction of the left ventricle to eject blood.
10
Go to www.bradybooks.com
and click on the mykit link for Prehospital
Emergency Care, 9th edition to access web
resources exploring Frank Starling’s Law.
Discussion Question
What is meant by cardiac output?
Teaching Tip
Explain the similarities in the concepts of
minute ventilation and cardiac output.
Critical Thinking Discussion
You’ve just been scared by a near collision
as you are driving to class. Explain how
your perfusion will be affected.
Discussion Question
What are the effects of the sympathetic and
parasympathetic nervous systems on
cardiac output?
Knowledge Application
Given several scenarios including a
patient’s stroke volume and heart rate,
calculate the cardiac output.
Discussion Question
How do changes in preload and afterload
affect cardiac output?
XII. Components Necessary for Adequate PerfusionSystemic
Vascular Resistance
A. Systemic vascular resistance is the resistance offered to blood flow through
a vessel.
1. Vasoconstriction is the decrease in vessel diameter.
2. Vasodilation is the increase in vessel diameter.
B. The basic measure of systemic vascular resistance is the diastolic blood
pressure.
PREHOSPITAL EMERGENCY CARE, 9TH EDITION
DETAILED LESSON PLAN 8
PAGE 8
C. A chronically elevated diastolic blood pressure will lead to heart failure.
D. The systemic vascular resistance is influenced by the autonomic nervous
system.
1. The sympathetic nervous system causes the vessels to constrict.
2. The parasympathetic nervous system causes the vessels to dilate.
E. Systemic Vascular Resistance Effect on Pulse Pressure
1. An increase in the systemic vascular resistance increases the diastolic
blood pressure.
2. A decrease in the systemic vascular resistance decreases the diastolic
blood pressure.
3. Pulse pressure is the difference between the systolic and diastolic blood
pressure readings.
Knowledge Application
Given several blood pressure values,
determine the pulse pressure.
Discussion Question
What is the significance of a narrow pulse
pressure?
XIII. Components Necessary for Adequate Perfusion—Microcirculation
10
A. Microcirculation is the flow of blood through the arterioles, capillaries, and
venules.
B. Arterioles control the movement of blood into the capillaries.
1. Vasoconstriction reduces blood flow to the capillaries.
2. Vasodilation increases blood flow to the capillaries.
C. Metarterioles connect arterioles and venules.
D. Percapillary sphincters control the movement of blood through the true
capillaries.
E. Control of blood flow through capillaries
1. Local factors, such as temperature, hypoxia, and acidosis
2. Neural factors, which are associated with the influence of the
sympathetic and parasympathetic nervous systems
3. Hormonal factors, such as the alpha1 stimulation from epinephrine
Discussion Question
How does the release of epinephrine and
norepinephrine increase perfusion?
XIV. Components Necessary for Adequate PerfusionBlood Pressure
10
A. Blood pressure equals the cardiac output times the systemic vascular
resistance.
1. An increase in the cardiac output or the heart rate will increase blood
pressure.
2. A decrease in the cardiac output or the heart rate will decrease blood
pressure.
3. An increase in the stroke volume or the systemic vascular resistance will
increase blood pressure.
4. A decrease in the stroke volume or the systemic vascular resistance will
decrease blood pressure.
B. Perfusion of cells is linked to blood pressure.
1. An increase in blood pressure will increase cellular perfusion.
2. A decrease in blood pressure will decrease cellular perfusion.
PREHOSPITAL EMERGENCY CARE, 9TH EDITION
DETAILED LESSON PLAN 8
Weblink
Go to www.bradybooks.com
and click on the mykit link for Prehospital
Emergency Care, 9th edition to access a
web resource relating cardiac output to
blood pressure.
PAGE 9
C. Regulation of blood pressure by baroreceptors and chemoreceptors
1. Baroreceptors are stretch-sensitive receptors that detect changes in
blood pressure and send impulses to the brain stem to make alterations
in blood pressure.
2. Chemoreceptors monitor the content of oxygen, carbon dioxide, and pH
of the blood, and cause the brainstem to trigger changes in the
sympathetic nervous system.
XI. Follow-Up
10
How do the nervous, respiratory, and
circulatory systems all have to work
together to maintain adequate perfusion?
Case Study Follow-Up Discussion
A. Answer student questions.
B. Case Study Follow-Up
1. Review the case study from the beginning of the chapter.
2. Remind students of some of the answers that were given to the
discussion questions.
3. Ask students if they would respond the same way after discussing the
chapter material. Follow up with questions to determine why students
would or would not change their answers.
C. Follow-Up Assignments
1. Review Chapter 8 Summary.
2. Complete Chapter 8 In Review questions.
3. Complete Chapter 8 Critical Thinking.
D. Assessments
1. Handouts
2. Chapter 8 quiz
PREHOSPITAL EMERGENCY CARE, 9TH EDITION
10
Critical Thinking Discussion
DETAILED LESSON PLAN 8
What is going on at the patient’s cellular
level?
 How can your actions help address the
problems at the patient’s cellular level?

Class Activity
Alternatively, assign each question to a
group of students and give them several
minutes to generate answers to present to
the rest of the class for discussion.
Teaching Tips

Answers to In Review and Critical
Thinking questions are in the appendix
to the Instructor’s Wraparound Edition.
Advise students to review the questions
again as they study the chapter.
 The Instructor’s Resource Package
contains handouts that assess student
learning and reinforce important
information in each chapter. This can be
found under mykit at
www.bradybooks.com.
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