2. DEFINITION
• Shock is a general term that refers to the
depression or suppression of body functions
produced by any disorder.
• Circulatory shock refers to the shock
developed by inadequate blood flow
throughout the body.
• It is a lifethreatening condition and it may
result in death if the affected person is not
treated immediately.
3. MANIFESTATIONS OF CIRCULATORY
SHOCK
• Following are the manifestations of circulatory
shock:
1. Whenever cardiac output is decreased, arterial
blood pressure drops down
2. Low blood pressure produces reflex tachycardia
and reflex vasoconstriction
3. Tachycardia decreases the diastolic period. So,
filling of the heart reduces leading to decrease
in stroke volume and systolic pressure. This
decreases the pulse pressure below 20 mm Hg.
Pulse also becomes feeble.
4. 4. Stagnant hypoxia develops because of decreased
velocity of blood flow
5. Skin becomes pale and cold due to the
vasoconstriction
6. Along with hypoxia, cyanosis also develops in
many parts of the body, particularly ear lobes and
fingertips
7. Glomerular filtration rate (GFR) and urinary
output are reduced due to fall in blood pressure
and constriction of renal blood vessels
8. Metabolic activities of myocardium are
accelerated because of reduced blood flow and
increased heart rate. A large amount of lactic acid
is produced, resulting in acidosis.
5. 9. Acidosis decreases myocardial efficiency and
pumping action of the heart leading to further
reduction in cardiac output
10. So, the blood flow to vital organs is severely
affected
11. Lack of blood flow to brain tissues produces
ischemia resulting in fainting and irreparable
damage of brain tissues
12. Finally the damage of brain tissues and
cardiac arrest kill the victim.
6. STAGES OF CIRCULATORY SHOCK
• Circulatory shock occurs in three stages:
1. First stage or compensated stage
2. Second stage or progressive stage
3. Third stage or irreversible stage.
10. TYPES AND CAUSES OF CIRCULATORY
SHOCK
• Circulatory shock is primarily classified into
four types.
A. Shock due to decreased blood volume
B. Shock due to increased vascular capacity
C. Shock due to cardiac disease
D. Shock due to obstruction of blood flow.
11.
12. Important Manifestations of
Hypovolemic Shock
1. Decrease in cardiac output
2. Low blood pressure
3. Thin thready pulse
4. Pale and cold skin
5. Increase in respiratory rate
6. Restlessness or lethargy.
14. 1. Hemorrhagic Shock
• Hemorrhagic shock is the shock due to
hemorrhage. Acute hemorrhage as in the case
of accident causes shock. Chronic hemorrhage
as in ulcers does not produce shock.
15. 2. Traumatic Shock
• Trauma means serious injury or wound caused
by some external force. Shock caused by
trauma is called traumatic shock. Shock occurs
due to the damage of muscles and bones,
which is common in battlefields and road
accidents. Apart from loss of blood, the
plasma escapes to the tissue spaces.
• Following are the common symptoms of
traumatic shock:
16. Crush syndrome
• Crush syndrome is the condition characterized by
renal failure when the limb of a person is crushed
or compressed in traumatic condition.
• Myoglobin and some toxic substances released
from affected muscles damage the renal tubular
cells leading to degeneration of renal tubules.
Stimulation of somatic afferents from the
damaged muscles causes constriction of renal
blood vessels.
• All these factors result in renal failure.
17. Reperfusion injury
• Reperfusion injury refers to dysfunction of
myocardium, blood vessels or any other tissue,
which is induced by restoration of blood flow to
previously ischemic tissue. It is also called injury
by reperfusion. Due to compression or damage
during traumatic conditions, the ischemic tissues
release some toxic substances. Later, when blood
supply is restored to the tissues again, the toxic
substances enter the tissues and cause further
damage of the tissues. Common instance is
myocardial reperfusion injury.
18. 3. Surgical Shock
• Surgical shock is the shock developed by
surgical procedures. Surgical shock develops
due to some reasons like internal hemorrhage,
external hemorrhage and dehydration that
occur during or after surgical procedures.
19. 4. Burn Shock
• Burn shock is the shock produced by the
effects of burn. In burns, loss of plasma
through the burnt surface is more than the
loss of whole blood. It decreases the ECF
volume and plasma volume, resulting in
hemoconcentration. This leads to sluggish
blood flow, which decreases the cerebral
blood flow causing shock.
20. 5. Dehydration Shock
• Shock due to dehydration is called
dehydration shock. Dehydration means
decrease in water content of the body. It
decreases the blood volume resulting in
shock.
21. SHOCK DUE TO INCREASED VASCULAR
CAPACITY – VASOGENIC SHOCK
• In this case, the blood volume is normal.
Shock occurs because of inadequate blood
supply to the tissues due to increased vascular
capacity.
• Capacity of the vascular system increases by
the extensive dilatation of blood vessels.
• It is also known as vasogenic or low resistance
or distributive shock.
22. Causes and Types of Vasogenic Shock
1. Sudden loss of vasomotor tone: Neurogenic
shock
2. Anaphylaxis: Anaphylactic shock
3. Sepsis: Septic shock.
23. 1. Neurogenic Shock
• Neurogenic shock is the type of shock
characterized by sudden depression of nervous
system due to extensive vasodilatation caused by
loss of vasomotor tone.
• Conditions when neurogenic shock develops
i. Ischemia of brain: Severe ischemia in medulla
depresses the activity of vasomotor center
ii. General anesthesia
iii. Spinal anesthesia
24. iv. Emotional conditions: Extreme emotions
cause sudden and exaggerated activity of
autonomic nervous system, the subject faints
because of neurogenic shock.
25.
26. 2. Anaphylactic Shock
• Anaphylaxis means exaggerated allergic reaction
to a foreign protein or antigen or any other
substance to which the person has been
previously sensitized.
• Shock that develops during anaphylactic
reactions is called anaphylactic shock. Shock
occurs because of vasodilatation and sudden fall
in blood pressure.
• It is caused by the chemical mediators such as
histamine that are secreted during anaphylactic
reaction.
27. 3. Septic Shock
• Sepsis is the pathological condition
characterized by the presence of pathogenic
organisms or their toxins in blood or tissues.
Shock developed during sepsis is known as
septic shock or blood poisoning
28. • Conditions when septic shock occurs
i. Infection of the uterus and fallopian tube,
commonly occurring in abortion by
instrumentation
ii. Infection of peritoneum
iii. Spreading of skin infection due to bacteria
like streptococci or staphylococci
iv. Spread of infection from any other part of
the body
29. Endotoxin shock
• Endotoxin shock is the shock developed by a
bacterial toxin called endotoxin. Endotoxin is a
lipopolysaccharide. It causes vasodilatation and
depresses myocardial activity.
• It also activates the macrophages to release
cytokines. Endotoxin shock is very common
during the infection of alimentary tract by gram-
negative bacteria like colon bacilli.
• It is actually released from dead bacteria.
Endotoxin shock can also occur in urinary tract
infection
30. SHOCK DUE TO CARDIAC DISEASES –
CARDIOGENIC SHOCK
• Shock due to cardiac disease is also called
cardiogenic shock.
Conditions when Cardiogenic Shock Occurs
1. Arrhythmia, particularly those which lead to
reduced cardiac output
2. Depressed activity of myocardium due to
ischemia
3. Congestive cardiac disease.
31. SHOCK DUE TO OBSTRUCTION OF
BLOOD FLOW – OBSTRUCTIVE SHOCK
• Shock developed due to the obstruction of
blood flow through circulatory system is called
obstructive shock.
Conditions when Obstructive Shock Occurs
1. Tumor in myocardium
2. Cardiac tamponade
3. Obstruction of blood vessels in lungs due to
embolism.
32. TREATMENT FOR CIRCULATORY
SHOCK
• Treatment for shock is based on the cause of the
shock. Following are the various measures taken
during the treatment of shock.
BLOOD TRANSFUSION
Transfusion of whole blood is done in hypovolemic
shock except burn shock. „
PLASMA TRANSFUSION
Plasma transfusion is very useful in burns or other
shocks in which there is loss of more plasma.
33. ADMINISTRATION OF PLASMA SUBSTITUTES
Plasma substitute is a solution of a substance that
is used for transfusion instead of plasma. Plasma
substitutes are used when plasma is not
available.
Commonly used Plasma Substitutes
i. Plasma expanders (solutions of sugar with high
molecular weight such as dextran); such
substances do not escape through capillary
membrane
ii. Concentrated human serum albumin
iii. Hypertonic solutions, which cause drawing of
fluid into blood from interstitial space.
34. ADMINISTRATION OF SYMPATHOMIMETIC
DRUGS
Sympathomimetic drugs like epinephrine and
norepinephrine are useful in neurogenic and
anaphylactic shocks, which occur due to
vasodilatation. These two drugs restore the
blood pressure by vasoconstriction. However,
the sympathomimetic drugs should not be
used for longer period since, these drugs
induce severe myocardial activity. In traumatic
and cardiogenic shocks, dopamine is used.
35. ADMINISTRATION OF GLUCOCORTICOIDS
Glucocorticoids are administered in serious
conditions. Glucocorticoids increase the
glucose metabolism in damaged tissues,
prevent further damage of tissues and
increase the myocardial activity.
36. OXYGEN THERAPY
• Oxygen therapy is given only in severe
conditions involving reduced oxygenation of
tissues.
37. BY CHANGING THE POSTURE
• This is the first measure to be taken in cases of
hemorrhagic and neurogenic shock. The head
down position (by raising the bed at the foot
end) increases venous return, cardiac output
and cerebral blood flow. However, this should
not be used for longer periods because
prolonged head down position might affect
the ventilation. It is because of effect of the
increased pressure exerted by abdominal
viscera on diaphragm.
