NUR 213
EXAM 4 3
STUDY GUIDE
Complex Health Concepts
Forsyth Technical Community College
This Document Description:
❖ This study guide for NUR 213 at Forsyth Technical
Community College focuses on Exam 4 content from the
Complex Health Concepts course.
❖ It includes essential topics.
❖ The material is clearly organized to help students understand complex
systems and prepare effectively for exam questions.
, NUR 213 – Unit 4 Study Guide
1. Exemplar: Shock
Shock: widespread abnormal cellular metabolism that occurs when has exchange and
oxygenation and tissue perfusion needs are not met sufficiently to maintain cell function. It is a
condition, rather than a disease and is the “whole body” response that occurs when too little
oxygen is delivered to the tissues. Shock is a syndrome because the problems resulting from it
occur in a predictable sequence. Any problem that impairs perfusion and gas exchange to tissues
and organs can start the syndrome of shock and lead to a life-threatening emergency.
When the body’s adaptive adjustments (compensation) or health care interventions are
not effective and shock progresses, it can lead to cell loss, multiple organ dysfunction
syndrome (MODS), and death.
Most S&S of shock are similar regardless of what starts the process or which tissues are
affected first. Symptoms result from physiologic adjustments (compensatory
mechanisms) that the body makes in the attempt to ensure continued perfusion of vital
organs. Compensatory actions are triggered by the sympathetic nervous system’s stress
response activating the endocrine and vascular system
Gas exchange and perfusion depend on how much oxygen from arterial blood perfuses
the tissue. Perfusion is related to MAP, and factors that influence MAP include the total
blood volume, cardiac output, and size/integrity of the vascular bed (capillaries)
Blood vessels are innervated by the sympathetic nervous system. Some blood vessels are
continuously stimulated so that the blood vessels are normally partially constricted
(sympathetic tone). Increases in sympathetic nervous system stimulation constrict smooth
muscle even more, raising MAP. Decreases in sympathetic tone relax smooth muscle,
dilating blood vessels and lowering MAP.
Although the causes and initial signs and symptoms associated with different types of
shock vary, eventually the effects of hypotension and anaerobic cellular metabolism will
result in common key features
Remember that more than one type of shock can be present at one time. Shock is
classified by the type of impairment causing it into different categories:
o Hypovolemic shock: occurs when too little circulating blood volume decreases
MAP, resulting in inadequate total body perfusion and gas exchange. Common
problems leading to hypovolemic shock are dehydration and poor clotting with
hemorrhage. Basic problem is that there is a loss of vascular volume, resulting in
a decrease MAP, and in some cases loss of RBCs. Reduced MAP slows blood
flow and decreases tissue perfusion. Loss of RBCs decreases the ability of the
blood to oxygenate the tissues it does reach. The loss of blood flow and loss of
oxygenation lead to anaerobic cellular metabolism.
Main trigger leading to hypovolemic shock is a sustained decrease in MAP
from decreased circulating blood volume
A decrease in MAP of 5-10 mmHg below the patient’s baseline is detected
by pressure-sensitive nerve receptors (baroreceptors) in the aortic arch and
carotid sinus. This information is transmitted to brain centers, which
stimulate compensatory mechanisms to help ensure continued blood flow
and oxygen delivery to vital organs while limiting blood flow to less vital
, areas. This movement of blood into selected areas while bypassing others
results in some shock symptoms.
If the events that caused the initial decrease in MAP are halted, the
compensatory mechanisms provide adequate gas exchange and perfusion
without intervention. If the events continue and decreases in MAP
decreases further, some tissues will function under anaerobic metabolism
– this condition increases lactic acid and other harmful metabolites. These
substances cause acidosis with tissue-damaging effects and depressed
heart muscle activity.
The effects are temporary and reversible IF the cause of shock is
reversed within 1-2 hours after onset
When shock continues for longer periods without help, the
resulting increased metabolites cause so much cell damage in vital
organs that they are unable to perform their critical functions. This
problem is known as multiple organ dysfunction syndrome
(MODS), and occurs to the extent that vital organs die, and
recovery from shock is no longer possible.
Etiology: occurs when too little circulating blood volume causes MAP
decrease the prevents total body perfusion and adequate gas exchange.
Hypovolemic shock from hemorrhage occurs with blunt trauma, GI ulcers,
and poor control of surgical bleeding. Can also be caused by any problems
leading to poor clotting. Hypovolemia from dehydration can be caused by
any problem that decreases fluid intake or increases fluid loss
Absolute:
Decreased volume of the fluid (blood) within the circulatory
system in which the fluid leaves the body, for example in bleeding.
o Loss of plasma (burns)
o Loss of water from the body (severe diarrhea or vomiting,
excessive sweating or urination)
Relative:
The fluid leaves the circulatory system and does not leave the
body.
o Vasodilation
o Some fluid leaves the circulatory system, but not the body,
for example in ascites, where the fluid accumulates in the
abdominal cavity.
Assessment:
History: ask about risk factors related to hypovolemic shock. If the
patient is alert, question them directly, if not alert, collect
information from family members. Ask about recent illnesses,
trauma, procedures, or chronic health problems:
o GI ulcers, general surgery, hemophilia, liver disorders,
prolonged vomiting diarrhea, for example
Ask about the use of drugs such as ASA, or other NSAIDs, and
diuretics that may cause damage leading to hypovolemic shock
Ask about fluid intake in the past 24 hours
, Ask about urine output, because decreased urine output is
especially important because urine output is reduced during the
first phases of shock, even when fluid intake is normal
Assess the patient for signs of poor clotting and hemorrhage
(gums, wounds, and sites of dressings, drains, and vascular access).
Check under the patient for blood
o Observe for any swelling or skin discoloration that may
indicate an internal hemorrhage
Shock may be first evident by changes in cardiovascular function,
as shock progresses, changes in the renal, respiratory,
integumentary, musculoskeletal, and central nervous systems
become evident
o Cardiovascular changes: decreased MAP, initial phase of
shock the pulse may be increase above the patients baseline
to keep CO and MAP at normal levels. Increased HR is the
first sign of shock. As shock progresses, peripheral pulses
are difficult to palpate and easily blocked, and a Doppler
may be needed. Changes in pulse rate and quality is used as
one of the main indicators of shock in the initial stage of
shock. With vasoconstriction, diastolic pressure increases,
but systolic pressure remains the same (narrowing pulse
pressure).
Systolic BP decreases as shock progresses and CO
decreases. When shock continues and interventions
are not adequate, compensation fails, both systolic
and diastolic pressures decrease, and BP is difficult
to hear
SpO2 of 99-95% usually occur in the non-
progressive stage, and values of 75-80% occur in
the progressive stage
o Respiratory Changes: adaptive response to help maintain
gas exchange when tissue perfusion is decreased
Asses rate and depth of respirations
RR increases during shock to ensure that oxygen
intake is increase so it can be delivered to critical
tissues
o Kidney and Urinary Changes: occurs with shock to
compensate for decreased MAP by saving body water
through decreased filtration and increased water absorption
Assess urine volume, color, specific gravity, and
presence of blood/protein
Decrease urine output is a sensitive indicator of
early shock
Measure urine output at least every hour
In severe shock, urine output may be absent
EXAM 4 3
STUDY GUIDE
Complex Health Concepts
Forsyth Technical Community College
This Document Description:
❖ This study guide for NUR 213 at Forsyth Technical
Community College focuses on Exam 4 content from the
Complex Health Concepts course.
❖ It includes essential topics.
❖ The material is clearly organized to help students understand complex
systems and prepare effectively for exam questions.
, NUR 213 – Unit 4 Study Guide
1. Exemplar: Shock
Shock: widespread abnormal cellular metabolism that occurs when has exchange and
oxygenation and tissue perfusion needs are not met sufficiently to maintain cell function. It is a
condition, rather than a disease and is the “whole body” response that occurs when too little
oxygen is delivered to the tissues. Shock is a syndrome because the problems resulting from it
occur in a predictable sequence. Any problem that impairs perfusion and gas exchange to tissues
and organs can start the syndrome of shock and lead to a life-threatening emergency.
When the body’s adaptive adjustments (compensation) or health care interventions are
not effective and shock progresses, it can lead to cell loss, multiple organ dysfunction
syndrome (MODS), and death.
Most S&S of shock are similar regardless of what starts the process or which tissues are
affected first. Symptoms result from physiologic adjustments (compensatory
mechanisms) that the body makes in the attempt to ensure continued perfusion of vital
organs. Compensatory actions are triggered by the sympathetic nervous system’s stress
response activating the endocrine and vascular system
Gas exchange and perfusion depend on how much oxygen from arterial blood perfuses
the tissue. Perfusion is related to MAP, and factors that influence MAP include the total
blood volume, cardiac output, and size/integrity of the vascular bed (capillaries)
Blood vessels are innervated by the sympathetic nervous system. Some blood vessels are
continuously stimulated so that the blood vessels are normally partially constricted
(sympathetic tone). Increases in sympathetic nervous system stimulation constrict smooth
muscle even more, raising MAP. Decreases in sympathetic tone relax smooth muscle,
dilating blood vessels and lowering MAP.
Although the causes and initial signs and symptoms associated with different types of
shock vary, eventually the effects of hypotension and anaerobic cellular metabolism will
result in common key features
Remember that more than one type of shock can be present at one time. Shock is
classified by the type of impairment causing it into different categories:
o Hypovolemic shock: occurs when too little circulating blood volume decreases
MAP, resulting in inadequate total body perfusion and gas exchange. Common
problems leading to hypovolemic shock are dehydration and poor clotting with
hemorrhage. Basic problem is that there is a loss of vascular volume, resulting in
a decrease MAP, and in some cases loss of RBCs. Reduced MAP slows blood
flow and decreases tissue perfusion. Loss of RBCs decreases the ability of the
blood to oxygenate the tissues it does reach. The loss of blood flow and loss of
oxygenation lead to anaerobic cellular metabolism.
Main trigger leading to hypovolemic shock is a sustained decrease in MAP
from decreased circulating blood volume
A decrease in MAP of 5-10 mmHg below the patient’s baseline is detected
by pressure-sensitive nerve receptors (baroreceptors) in the aortic arch and
carotid sinus. This information is transmitted to brain centers, which
stimulate compensatory mechanisms to help ensure continued blood flow
and oxygen delivery to vital organs while limiting blood flow to less vital
, areas. This movement of blood into selected areas while bypassing others
results in some shock symptoms.
If the events that caused the initial decrease in MAP are halted, the
compensatory mechanisms provide adequate gas exchange and perfusion
without intervention. If the events continue and decreases in MAP
decreases further, some tissues will function under anaerobic metabolism
– this condition increases lactic acid and other harmful metabolites. These
substances cause acidosis with tissue-damaging effects and depressed
heart muscle activity.
The effects are temporary and reversible IF the cause of shock is
reversed within 1-2 hours after onset
When shock continues for longer periods without help, the
resulting increased metabolites cause so much cell damage in vital
organs that they are unable to perform their critical functions. This
problem is known as multiple organ dysfunction syndrome
(MODS), and occurs to the extent that vital organs die, and
recovery from shock is no longer possible.
Etiology: occurs when too little circulating blood volume causes MAP
decrease the prevents total body perfusion and adequate gas exchange.
Hypovolemic shock from hemorrhage occurs with blunt trauma, GI ulcers,
and poor control of surgical bleeding. Can also be caused by any problems
leading to poor clotting. Hypovolemia from dehydration can be caused by
any problem that decreases fluid intake or increases fluid loss
Absolute:
Decreased volume of the fluid (blood) within the circulatory
system in which the fluid leaves the body, for example in bleeding.
o Loss of plasma (burns)
o Loss of water from the body (severe diarrhea or vomiting,
excessive sweating or urination)
Relative:
The fluid leaves the circulatory system and does not leave the
body.
o Vasodilation
o Some fluid leaves the circulatory system, but not the body,
for example in ascites, where the fluid accumulates in the
abdominal cavity.
Assessment:
History: ask about risk factors related to hypovolemic shock. If the
patient is alert, question them directly, if not alert, collect
information from family members. Ask about recent illnesses,
trauma, procedures, or chronic health problems:
o GI ulcers, general surgery, hemophilia, liver disorders,
prolonged vomiting diarrhea, for example
Ask about the use of drugs such as ASA, or other NSAIDs, and
diuretics that may cause damage leading to hypovolemic shock
Ask about fluid intake in the past 24 hours
, Ask about urine output, because decreased urine output is
especially important because urine output is reduced during the
first phases of shock, even when fluid intake is normal
Assess the patient for signs of poor clotting and hemorrhage
(gums, wounds, and sites of dressings, drains, and vascular access).
Check under the patient for blood
o Observe for any swelling or skin discoloration that may
indicate an internal hemorrhage
Shock may be first evident by changes in cardiovascular function,
as shock progresses, changes in the renal, respiratory,
integumentary, musculoskeletal, and central nervous systems
become evident
o Cardiovascular changes: decreased MAP, initial phase of
shock the pulse may be increase above the patients baseline
to keep CO and MAP at normal levels. Increased HR is the
first sign of shock. As shock progresses, peripheral pulses
are difficult to palpate and easily blocked, and a Doppler
may be needed. Changes in pulse rate and quality is used as
one of the main indicators of shock in the initial stage of
shock. With vasoconstriction, diastolic pressure increases,
but systolic pressure remains the same (narrowing pulse
pressure).
Systolic BP decreases as shock progresses and CO
decreases. When shock continues and interventions
are not adequate, compensation fails, both systolic
and diastolic pressures decrease, and BP is difficult
to hear
SpO2 of 99-95% usually occur in the non-
progressive stage, and values of 75-80% occur in
the progressive stage
o Respiratory Changes: adaptive response to help maintain
gas exchange when tissue perfusion is decreased
Asses rate and depth of respirations
RR increases during shock to ensure that oxygen
intake is increase so it can be delivered to critical
tissues
o Kidney and Urinary Changes: occurs with shock to
compensate for decreased MAP by saving body water
through decreased filtration and increased water absorption
Assess urine volume, color, specific gravity, and
presence of blood/protein
Decrease urine output is a sensitive indicator of
early shock
Measure urine output at least every hour
In severe shock, urine output may be absent
