Chapter 39 Care of Patients with Shock
Review of oxygenation & tissue perfusion
Oxygenation & perfusion depend on how much oxygen from arterial blood perfuses the tissue.
Tissue & organ perfusion is related to mean arterial pressure (MAP)
Causes & types of shock by functional impairment
-Hypovolemic shock- Total body fluid decreased (in all fluid compartments)
Specific Cause or risk factors- trauma, GI ulcer, surgery, inadequate clotting- hemophilia, liver disease,
malnutrition, bone marrow suppression, cancer,anticoagulation therapy, diabetes insipidus, -
Dehydration' hyperglycemia, vomiting, diarrhea, heavy diaphoresis, diuretic therapy, Nasogatric suction
-Cardiogenic shock
Direct pump failure (fluid volume not affected), specific cause or risk factor- myocardial Infarction,
cardiac arrest, ventricular dysrhythmias (v fib, v tachy), cardiac amylodosis, cardiomyopathies- viral,
toxic, myocardial degeneration.
-Distributive shock- Fluid shifted from central vascular space (total body fluid volume normal or
increased)- neural-induced, pain, anesthesia, stress, head trauma, chemical-induce- anaphylaxis,
capillary leak, burns extensive- trauma, liver impairment
,Obstructive shock- Cardiac function decreased by non cardiac factor (indirect pump failure) total body
fluid is not affected although central volume is decreased . Specific Cause or risk factors- Cardiac
tamponade, arterial stenosis, pulmonary embolism, pulmonary hypertension, constructive pericarditis,
thoracic tumors, tension pneumothorax.
Key features:Shock
Cardiovascular manifestations: decreased cardiac output, increased pulse rate, thready pulse, decreased
BP, narrowed pulse pressure, postural hypotension ¥, low central venous pressure, flat neck & hand
veins in dependent positions, alow capillary refill nailbeds
Respiratory - increased respiratory rate, shallow depth of respirations, increased paco2, increased
paco2, cyanosis (lips & nail beds)
Neuromuscular- anxiety, restlessness, increased thirst
LATE- Decreased CNS activity (lethargy to coma); Generalized muscle weakness, diminished or absent
deep tendon reflexes, sluggish pupillary response to light.
KIDNEY- decreased urine output; increased specific gravity; sugar & acetone present in urine
INTEGUMENTARY- Cool to cold; pale to mottled to cyanotic; moist, clammy; mouth dry; pastelike
coating presenting
GASTROINTESTINAL- Decreased motility; diminished or absent bowel sounds; nausea & vomiting;
constipation.
TYPE OF SHOCKS- HYPOVOLEMIC
,-occurs when too little circulating blood volume causes a MAP decrease, resulting in inadequate total
body oxygenation- Reduced MAP slows blood flow resulting in decreased tissue perfusion.
-Common problems leading: hemorrhage & dehydration
CARDIOGENIC SHOCK
Occurs when the actual heart muscle is unhealthy & pumping & is directly impaired.
Myocardial infarction- most common cause of direct pump failure.
DISTRIBUTIVE SHOCK
Occurs when blood volume is not lost from the body but is distributed to the interstitial tissues where it
can't circulate & deliver oxygen.
Can be caused by loss of sympathetic tone, blood vessel dilation, pooling of blood in venous & capillary
beds, & increased capillary leak.
NEURAL-INDUCED DISTRIBUTIVE SHOCK
A loss of MAP that occurs when sympathetic nerve impulses controlling blood vessel smooth muscle
muscle are decreased & the smooth muscles relax, causing vasodilation.
CHEMICAL INDUCED DISTRIBUTIVE SHOCK
3 common origins:
, -anaphylaxis- one result of type I allergic reactions. Result is widespread loss of blood vessel tone &
decreased cardiac output.
-Sepsis- widespread infection that triggers a whole body inflammatory response. Leads to distributive
shock when infectious microorganisms are present in blood.
-Capillary leak syndrome- The response of capillaries to the presence of biologic mediators that change
blood vessel integrity & allow fluid to shift from the blood vessels into the interstitial tissues. One in
tissue, fluids are stagnant & can't deliver oxygen or remove tissue waste products.
-Occurs when certain body chemicals or foreign substances in the blood & vessels start widespread
changes in blood vessel walls.
-Problems causing fluid shift: severe burns, liver disorders, ascites, peritonitis, paralytic ileus, severe
malnutrition, large wounds .
OBSTRUCTIVE SHOCK
Caused by problems that impair the ability of the normal heart muscle to pump effectively. The heart
itself remains normal, but conditions outside the heart prevent either adequate filling of the heart or
adequate contraction of the healthy heart muscle.
-Most common causes: pericarditis & cardiac tamponade
Adaptive Responses & Events During Hypovolemic
INITIAL STAGE- Decrease in baseline MAP of 5-10. Increased sympathetic stimulation- mild
vasoconstriction; increased HR.
NONPROGRESSIVE STAGE- Decrease in MAP of 10-15 from patient's baseline value. Continued
sympathetic stimulation- moderate vasoconstriction; increased HR; decreased pulse pressure; Chemical
compensation- renin aldosterone & antidiuretic hormone secretion, increased vasoconstriction;
Review of oxygenation & tissue perfusion
Oxygenation & perfusion depend on how much oxygen from arterial blood perfuses the tissue.
Tissue & organ perfusion is related to mean arterial pressure (MAP)
Causes & types of shock by functional impairment
-Hypovolemic shock- Total body fluid decreased (in all fluid compartments)
Specific Cause or risk factors- trauma, GI ulcer, surgery, inadequate clotting- hemophilia, liver disease,
malnutrition, bone marrow suppression, cancer,anticoagulation therapy, diabetes insipidus, -
Dehydration' hyperglycemia, vomiting, diarrhea, heavy diaphoresis, diuretic therapy, Nasogatric suction
-Cardiogenic shock
Direct pump failure (fluid volume not affected), specific cause or risk factor- myocardial Infarction,
cardiac arrest, ventricular dysrhythmias (v fib, v tachy), cardiac amylodosis, cardiomyopathies- viral,
toxic, myocardial degeneration.
-Distributive shock- Fluid shifted from central vascular space (total body fluid volume normal or
increased)- neural-induced, pain, anesthesia, stress, head trauma, chemical-induce- anaphylaxis,
capillary leak, burns extensive- trauma, liver impairment
,Obstructive shock- Cardiac function decreased by non cardiac factor (indirect pump failure) total body
fluid is not affected although central volume is decreased . Specific Cause or risk factors- Cardiac
tamponade, arterial stenosis, pulmonary embolism, pulmonary hypertension, constructive pericarditis,
thoracic tumors, tension pneumothorax.
Key features:Shock
Cardiovascular manifestations: decreased cardiac output, increased pulse rate, thready pulse, decreased
BP, narrowed pulse pressure, postural hypotension ¥, low central venous pressure, flat neck & hand
veins in dependent positions, alow capillary refill nailbeds
Respiratory - increased respiratory rate, shallow depth of respirations, increased paco2, increased
paco2, cyanosis (lips & nail beds)
Neuromuscular- anxiety, restlessness, increased thirst
LATE- Decreased CNS activity (lethargy to coma); Generalized muscle weakness, diminished or absent
deep tendon reflexes, sluggish pupillary response to light.
KIDNEY- decreased urine output; increased specific gravity; sugar & acetone present in urine
INTEGUMENTARY- Cool to cold; pale to mottled to cyanotic; moist, clammy; mouth dry; pastelike
coating presenting
GASTROINTESTINAL- Decreased motility; diminished or absent bowel sounds; nausea & vomiting;
constipation.
TYPE OF SHOCKS- HYPOVOLEMIC
,-occurs when too little circulating blood volume causes a MAP decrease, resulting in inadequate total
body oxygenation- Reduced MAP slows blood flow resulting in decreased tissue perfusion.
-Common problems leading: hemorrhage & dehydration
CARDIOGENIC SHOCK
Occurs when the actual heart muscle is unhealthy & pumping & is directly impaired.
Myocardial infarction- most common cause of direct pump failure.
DISTRIBUTIVE SHOCK
Occurs when blood volume is not lost from the body but is distributed to the interstitial tissues where it
can't circulate & deliver oxygen.
Can be caused by loss of sympathetic tone, blood vessel dilation, pooling of blood in venous & capillary
beds, & increased capillary leak.
NEURAL-INDUCED DISTRIBUTIVE SHOCK
A loss of MAP that occurs when sympathetic nerve impulses controlling blood vessel smooth muscle
muscle are decreased & the smooth muscles relax, causing vasodilation.
CHEMICAL INDUCED DISTRIBUTIVE SHOCK
3 common origins:
, -anaphylaxis- one result of type I allergic reactions. Result is widespread loss of blood vessel tone &
decreased cardiac output.
-Sepsis- widespread infection that triggers a whole body inflammatory response. Leads to distributive
shock when infectious microorganisms are present in blood.
-Capillary leak syndrome- The response of capillaries to the presence of biologic mediators that change
blood vessel integrity & allow fluid to shift from the blood vessels into the interstitial tissues. One in
tissue, fluids are stagnant & can't deliver oxygen or remove tissue waste products.
-Occurs when certain body chemicals or foreign substances in the blood & vessels start widespread
changes in blood vessel walls.
-Problems causing fluid shift: severe burns, liver disorders, ascites, peritonitis, paralytic ileus, severe
malnutrition, large wounds .
OBSTRUCTIVE SHOCK
Caused by problems that impair the ability of the normal heart muscle to pump effectively. The heart
itself remains normal, but conditions outside the heart prevent either adequate filling of the heart or
adequate contraction of the healthy heart muscle.
-Most common causes: pericarditis & cardiac tamponade
Adaptive Responses & Events During Hypovolemic
INITIAL STAGE- Decrease in baseline MAP of 5-10. Increased sympathetic stimulation- mild
vasoconstriction; increased HR.
NONPROGRESSIVE STAGE- Decrease in MAP of 10-15 from patient's baseline value. Continued
sympathetic stimulation- moderate vasoconstriction; increased HR; decreased pulse pressure; Chemical
compensation- renin aldosterone & antidiuretic hormone secretion, increased vasoconstriction;
