Chapter 7
Shock
Objective
 To master the concept of shock, etiology and classification
of shock, initial factors of shock, stages and mechanisms of
microcirculatory
disorder
of
shock,
compensatory
significance of microcirculatory changes and clinical
manifestation in different stages of shock.
 To
understand
the
pathogenesis
of
multiple
organ
dysfunction syndrome and cellular injuries and metabolic
disorders.
Self-assessment
Ⅰ. True or false questions (mark √ for true question, mark  for false question.
If it is false, correct it. )
1. The blood pressure of patient must decrease during the early stage of shock.
(×)
2. The blood volume flowed into coronary and cerebral vessels increase
because of compensated blood distribution. (√)
3. All of microvessels in microcirculation strongly constrict during the early
stage of shock. (×)
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4. Three initial factors resulting in shock are decreased blood volume,
dysfunction of heart pump, decreased vascular capacity. (×)
5. DIC and MODS may happen in the refractory stage of shock. (√)
Ⅱ. Single choice questions
1. What is the most basic pathogenesis of shock?
A) Blood pressure ↓
B) coma
(D)
C) Hypovolemic volume
D) Dysfunction of microcirculatory perfusion
E) Microvessels constriction
2. Which of the following changes of microcirculation may occur at early stage
of shock? (A)
A) Precapillary sphincter constriction
B) Blood cells aggregate and adhere
C) No-reflow
D) Blood viscosity increases
E) Arteriovenous shunt closes
3. The etiologies of hypovolemic volume include the following causes except:
(C)
A) Blood loss
B) Dehydration
C) Infection
D) Burn injury
E) Ascites
4. Which of the following symptoms is not inevitable to occur during the early
stage of hypovolemic shock? (C)
A) Heart rate↑
B) oliguria
C) Blood pressure↓
D) Body temperature↓
E) Narrowing pulse pressure
5. Which of the following cytokines is not a vasodilator: D
A) Lactic acid
B) Histamine
C) Kinin
D) ADH
E) NO
6. Which of the following changes doesn’t occur at the early stage of
hypovolemic shock? (D)
A) Arteriole constricts
B) Venule constricts
C) Capillary blood flow decreases
D) Arteriovenous shunt close
E) precapillary sphincter constricts
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7. The so called “Auto-blood transfusion” compensation during early stage of
hypovolemic shock mostly results from? (B)
A) Arteriovenous shunt opens, blood flow return to heart.
B) Venous constriction, “reservoir” blood returns
C) ↑Aldosterone, reabsorb sodium and water
D) ↑ADH, reabsorb water
E) ↑RBC
8. The so called “Auto-fluid transfusion” compensation during early stage of
hypovolemic shock mostly results from? (E)
A) Venous constriction, “reservoir” returns
B) ↑ADH, reabsorb water
C) Arteriovenous shunt opens, blood flow return to heart.
D) ↑Aldosterone, reabsorb sodium and water
E) ↓capillary hydrostatic pressure, fluid returns to vascular compartment from
interstitial fluid.
9. The so called “blood distribution” compensation during early stage of
hypovolemic shock means? (A)
A) ↑ blood flow into heart
B) ↓blood flow into brain
C) ↑blood flow into kidney
D) ↑blood flow into skin
E) ↑blood flow into intestine
10. Which one is a possible change in microcirculation at the progressive
stage (decompensated stage) of hypovolemic shock? (B)
A) Microvessles constrict
B) Microvessles dilate
C) ↓vasodilators
D) True capillary closes off
E) Blood viscosity decreases
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Ⅲ. Multiple choice questions
1. Which of the following factors may cause hypovolemic shock? (ABDE)
A) Blood loss
B) Burns
C) Myocardial infarction
D) Gastrointestinal fluid loss
E) Dehydration caused by excessive perspiration
2. In the early (compensatory) stage of hypovolemic shock, which signs and
symptoms can be observed? (ABCDE)
A. Tachycardia and thread-pulse due to sympathetic stimulation
B. Restlessness and anxiousness
C. Narrowing pulse pressure
D. Reduced urine volum secondary to vasoconstriction
E. Cool, pale skin associated with vasoconstriction
3. Which of the following mechanisms may lead to stasis and hypoxia in
microcirculation during the progressive stage (decompensated stage)?
(ABCDE)
A. Prolonged anaerobic glycolysis → lactic acid↑
B. Local accumulation of metabolic products
C. Alteration of hemorheology and ↑vascular permeability
D. Endotoxin absorbed from ischemic intestine
E. Vasodilators: NO, TXA 2, TNF, TL-1
4. Which of the following humoral factors may constrict the microvesseles
during the early stage of hypovolemic shock as a vasoconstrictor? (ABCE)
A. Catecholamine
B. Angiotensin Ⅱ
C. Vasopressin,
D. NO
E. TXA2
5. Which of the following compensations may occur at the early stage of
hypovolemic shock? (ABCDE)
A. Auto-blood transfusion to increase blood volume
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B. Auto-fluid transfusion to increase blood volume
C. Blood distribution to protect important organs
D. Elevated peripheral resistance to maintain blood pressure
E. Elevated cardiac output to maintain blood pressure
Ⅳ. Clinical case and short questions
A young man was brought to the emergency department by ambulance at the
next day after a severe traffic accident. He is unconscious. BP: 78/48mmHg,
heart rate is 130bpm. There is no evidence of head trauma. He withdraws to
pain. Cardiac examination reveals no murmurs or rubs. The lungs are clear to
auscultation. The abdomen is tense, with decreased bowel sounds. The
patient shows cyanosis, with thready pulses.
Questions:
1. What kind of fundamental pathological process did happen to this
patient?
Hypovolemic shock.
2. Please explain the compensation of sympathetic response during the
early stage of shock.
(1) Auto-blood transfusion: venous constriction  “reservoir”return
(2) Auto-fluid transfusion: arteriole, metarteriole and pre sphincter
constriction  capillary hydrostatic pressure falls down fluid return to
vascular compartment from interstitial fluid.
(3) blood distribution : coronary and cerebral vessels are less sensitive to
the sympathetic response than skin and visceral vessels  decreased
blood volume flows through heart and brain Keep important organs
from injury.
(4) elevated blood volume : Arterio venous shunt opens, sodium and water
retention
(5) elevated cardiac output : Increased cardiac contractility, conduction
and heart rate
(6) elevated peripheral resistance: vessel constriction maintain systemic
blood pressure
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