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Chapter 19
Shock
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Definition of Shock
• Inadequate tissue perfusion resulting in
impaired cellular metabolism
• Deprives cells of essential oxygen and nutrients,
forcing cells to rely on anaerobic (without oxygen)
metabolism
• Less energy is produced and lactic acid, a byproduct of anaerobic metabolism, causes
tissue acidosis and subsequent organ
dysfunction
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Hypovolemic Shock
• Inadequate blood volume to maintain the supply of
oxygen and nutrients to body tissues
• Intravascular or circulating volume deficits can occur
from external or internal losses
• Blood volume falls with excessive blood or fluid loss,
inadequate fluid intake, or a shift of plasma from the
blood vessels into body tissues/organs
• Causes of blood/fluid loss: hemorrhage, severe
diarrhea or vomiting, excessive perspiration
• Excessive shift of plasma with pathologic states (burns,
peritonitis, and intestinal obstruction)
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Cardiogenic Shock
• Occurs when heart fails as a pump
• Decreased myocardial contractility causes
decreased cardiac output and impaired tissue
perfusion
• Difficult to treat and usually results when
diseased coronary arteries cannot meet the
demand of the working myocardial cells
• Causes include conditions that result in
ineffective myocardial cell function, such as
dysrhythmias, cardiomyopathy, myocarditis,
valvular disease, and structural disorders
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Obstructive Shock
• Physical impairment of adequate circulating
blood flow
• Obstruction of the heart or great vessels either
blocks venous return to the right side of the
heart or prevents effective pumping action
• Causes: tension pneumothorax, pericardial
tamponade, pulmonary embolus, abdominal
distention, and aortic dissection
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Distributive Shock
• The problem is not loss of blood, but excessive
dilation of blood vessels or decreased vascular
resistance causing the blood to be improperly
distributed
• Fluid pools in dependent areas of body and is
not returned to the arterial circulation to supply
critical cellular metabolic needs
• Complicated by increased capillary
permeability; plasma leaks into interstitial
compartment, decreasing intravascular blood
volume
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Distributive Shock
• Anaphylactic shock
• A severe allergic reaction that results in the release
of chemicals that dilate blood vessels and increase
capillary permeability
• Fluid leaks out of capillaries into the tissues
• Pooling of blood in peripheral tissues and the shift of
fluid out of the capillaries cause venous return and
cardiac output to fall
• Allergic reaction also causes constriction of the
bronchi and airway obstruction
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Distributive Shock
• Septic shock
• Hypotension unresponsive to fluid resuscitation
along with metabolic acidosis, acute
encephalopathy, oliguria, and/or coagulation
disorders
• Pathogenic organisms (bacteria, fungi, viruses,
rickettsiae) release toxic substances that cause
blood vessels to dilate and decrease vascular
resistance and increase capillary permeability
• Increased permeability: leakage of plasma proteins
and reduced intravascular volume, preload, and
cardiac output that contributes to inadequate tissue
perfusion and oxygenation
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Distributive Shock
• Neurogenic shock
• Disruption in the nervous system affects the
vasomotor center in the medulla
• Disrupted sympathetic nerve impulses result in
vasodilation or loss of vascular resistance
• Signs and symptoms: pooling of blood in peripheral
tissues with subsequent decreased venous return
and cardiac output; bradycardia with hypotension
• Causes: injury or disease of the upper spinal cord,
spinal anesthesia, depression of the vasomotor
center from certain drugs
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Effects of Shock on
Body Systems and Functions
• Respiratory system
• Tissue hypoxia and anoxia, respiratory failure, acute
respiratory distress syndrome (ARDS)
• Acid-base balance
• Metabolic acidosis
• Cardiovascular system
• Myocardial depression, disseminated intravascular
coagulation (widespread clotting caused by sluggish
flow of acidic blood combined with bacterial
endotoxins or clotting factors released by
destruction of red blood cells)
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Effects of Shock on
Body Systems and Functions
• Neuroendocrine system
• Release of catecholamines (epinephrine and
norepinephrine), mineralocorticoids (aldosterone
and desoxycorticosterone), glucocorticoids
(hydrocortisone), and antidiuretic hormone;
decreased level of consciousness when cerebral
blood flow falls
• Immune system
• Depressed immune response
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Effects of Shock on
Body Systems and Functions
• Gastrointestinal system
• Decreased peristalsis, ischemia of intestinal
submucosa, impaired liver function
• Renal system
• Reduced glomerular filtration, inadequate renal
perfusion, tubular necrosis, renal ischemia
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Stages of Shock
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Early, Reversible, and
Compensatory Stages
• Continued reduction in cardiac output triggers set of
neural, endocrine, and chemical compensatory
mechanisms in an effort to overcome the
consequences of anaerobic metabolism and maintain
blood flow to vital organs
• During this stage the following may occur:
• Activation of baroreceptors in the carotid arteries and the aorta
stimulate the sympathetic nervous system
• Sympathetic stimulation: increased heart rate, constriction of
peripheral blood vessels, and reduced blood flow to the
kidneys, lungs, muscles, skin, and gastrointestinal (GI) tract
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Early, Reversible, and
Compensatory Stages
• Events
• Decreased renal blood flow triggers the release of renin and a
sequence of events that produces angiotensin II
• Adrenal cortex secretes aldosterone, which promotes sodium
retention by the kidneys
• Antidiuretic hormone released by posterior pituitary, resulting
in additional retention of water by the kidneys
• Falling blood pH and increasing arterial carbon dioxide
detected by chemoreceptors in the carotid arteries, which
stimulate the respiratory center
• Increased respiratory rate and depth help to eliminate excess
carbon dioxide and normalize the blood pH
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Early, Reversible, and
Compensatory Stages
• Symptoms
• Mental status
• Irritability, restlessness
• Blood pressure
• Normal or slightly decreased, decreasing pulse pressure,
orthostatic hypotension
• Pulse
• Increased rate; may be thready (as a result of
vasoconstriction) or bounding (caused by vasodilation)
decreased rate (bradycardia) may be present in neurogenic
shock due to loss of sympathetic stimulation
•
Respirations
• Increased rate and depth
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Early, Reversible, and
Compensatory Stages
• Urine output
• Decreased
• Skin
• Cool and pale
• Exception: warm and dry with septic shock
• Abdomen
• Decreased bowel sounds
• Blood glucose
• Increased
• Other
• Thirst
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Intermediate (Progressive) Stage
• Cause of shock is not corrected or if compensatory
mechanisms continue without reversing the shock
• Neural, endocrine, chemical compensatory
mechanisms begin to function independently and in
opposition
• Systemic circulation continues to vasoconstrict in the
attempt to maintain blood flow to vital organs
• Decrease in peripheral blood flow leads to weak or
absent pulses and ischemia of the extremities
• Blood becomes more viscous or thick, causing
clumping of red blood cells, platelets, and proteins
• Deprived of oxygen, cells resort to anaerobic
metabolism and produce lactic acid, resulting in
metabolic acidosis
• Depressant effect on myocardial cells
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Intermediate (Progressive) Stage
• Symptoms
• Mental status
• Listlessness, confusion
• Blood pressure
• Decreased; narrow pulse pressure
• Pulse
• Weak and thready, tachycardia, dysrhythmias
• Respirations
• Increased, deep, crackles present on auscultation
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Intermediate (Progressive) Stage
• Temperature
• Subnormal, except with septic shock
• Urine output
• Decreased; possible renal failure
• Skin
• Cold, pale, clammy, slow capillary refill, cyanosis
• Other
• Dry mouth, thirst, sluggish pupillary response,
peripheral edema, and muscle weakness
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Irreversible (Refractory) Stage
• Irreversible changes in vital organs as compensatory
mechanisms fail
• Tissue perfusion deteriorates, as blood remains pooled
in the capillary bed where sluggish flow is further
compromised by clumping and the formation of clots
• Coronary artery perfusion is reduced causing ischemia
and dysrhythmias
• Cerebral ischemia occurs as a result of the decrease in
cerebral blood flow
• Death is imminent
• Even patients who are resuscitated during this stage often die
within a week or two
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Irreversible (Refractory) Stage
• Symptoms
• Mental status
• Loss of consciousness
• Blood pressure
• Systolic continues to fall; diastolic approaches zero
• Pulse
• Progressive slowing, irregular
• Respirations
• Slow, shallow, irregular
• Urine output
• Minimal
• Skin
• Cold, clammy, cyanosis
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Diagnosis
• Based on history and physical examination
• Tests and procedures that help establish type
of shock, stage, and the cause
• Blood and urine studies, measurement of
hemodynamic pressures, chest radiograph, ECG
and continuous cardiac monitoring, pulse oximetry
and arterial blood gases, and urine output
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First Aid for Shock Outside the
Medical Facility
• Treatment provided before medical care is
available can have a significant effect on the
chances of survival
• Healthy People 2010 objectives (2000): the
necessity for increasing public awareness of
how and whom to call for emergency
assistance in addition to providing education
concerning initial lifesaving procedures to be
followed until arrival of emergency responders
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Oxygenation
• Brain cells begin to die after 4 minutes without
oxygen, and oxygen consumption increases as
delivery decreases in shock: poor prognosis
• Oxygen delivery such as increasing arterial
oxygen saturation, hemoglobin, and cardiac
output
• Supplemental oxygen may be used or
mechanical ventilation may be necessary
• Paralytics, sedatives, and analgesics may be
ordered to decrease oxygen requirements
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Fluid Replacement
• Normal saline is usually administered initially
• Subsequent fluids may include various
crystalloids and colloids depending on situation
• Crystalloids provide replacement water and
electrolytes for all fluid compartments
• Colloids remain in the vascular system and draw
fluid into the bloodstream
• Especially important when large amounts of plasma proteins have
been lost
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Pharmacologic Therapy
• Based on manipulation of the cardiac
dynamics: contractility, preload, afterload, and
heart rate
• No one drug will provide nutrients and oxygen
to the cells; several agents assist in
manipulation of the four circulatory
components
• See the Drug Therapy table on pp. 294-295
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Mechanical Management
• Management of shock may include the use of
mechanical devices that assist in the
restoration of cellular perfusion
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Figure 19-1
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Figure 19-2
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Nursing Care of the Patient in
Shock
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Assessment
• Continuous monitoring of cardiac rate and
rhythm; blood pressure; body temperature;
hemodynamic values; respiratory rate, rhythm,
and depth; and arterial blood gases
• Observe skin color; palpate for warmth and
moisture
• Note pupil size, equality, and response to light
• Describe patient’s level of consciousness and
response to commands, and assess reflexes
• Auscultate heart, lung, and bowel sounds
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Assessment
• Observe movement of the chest wall with
respirations; inspect and palpate abdomen for
distention
• Palpate for bladder distention, and note the
appearance of urine and the hourly output
• Inspect the extremities for color, and palpate
for peripheral pulses and edema
• Inspect IV infusion sites for pallor, swelling, or
coolness that suggests extravasation
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Interventions
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Nursing Diagnosis
• The primary nursing diagnosis for all patients in
shock is Altered Tissue Perfusion
• May be related to alteration(s) in circulating
blood volume, myocardial contractility, blood
flow, or vascular resistance
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Ineffective Tissue Perfusion
• Assessment must include all body systems
• If not corrected, shock eventually results in
failure of all major organs
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Decreased Cardiac Output
• Administer intravenous fluids as ordered
• Assess for fluid volume deficit and excess
• Administer inotropic and antidysrhythmic
agents as ordered; continuous cardiac
monitoring
• Maintain adequate body heat
• Fever may be treated with acetaminophen or
nonsteroidal anti-inflammatory drugs
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Disturbed Thought Processes and
Anxiety
• May be anxious, then confused and disoriented, and
finally unconscious
• Remain calm; give simple explanations of what is
being done
• Protect patient from constant, excessive noise and light
• Repeat orientation, instructions, and reassurance often
• In the presence of unconscious patients, remember
that they may hear even when they cannot respond
• Continue to speak to the patient and beware of negative
comments
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Deficient Fluid Volume
• Monitor for hypovolemia
• Tachycardia, hypotension, tachypnea, decreased
urine output, and decreased central venous
pressure and pulmonary artery pressure
• Administer intravenous fluids cautiously while
assessing output of urine
• Assess for fluid overload
• Full, bounding pulse; dilute urine, increased
respiratory rate; abnormal lung sounds; dyspnea;
and edema
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Risk for Injury
• Related to changes in consciousness
• Related to therapeutic measures
• Antidysrhythmics can depress cardiac activity
• Anticoagulants can permit excessive bleeding
• Extravasation of vasopressors (drugs that raise
blood pressure by vasoconstriction) can cause local
tissue necrosis
• High risk for complications of immobility
• Personal hygiene may be limited by the
patient’s tolerance of such activity
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Risk for Infection
• IV lines, indwelling urinary catheters, chest tubes,
airways, ventricular assist devices, and other
equipment provide avenues for infection in patient in
shock
• Wash your hands thoroughly between patients
• Follow agency guidelines for care of IV and urinary
catheters
• Use aseptic technique when inserting these devices,
caring for insertion sites, and providing wound care
• Monitor for signs of infection
• When antibiotics are ordered, administer them on
schedule to maintain a therapeutic blood level
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Ineffective Family Coping
• Be sensitive to the needs of the family for
information and support
• Explain the nursing care and encourage them
to ask questions
• Offer the services of a counselor or patient
representative
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Systemic Inflammatory
Response Syndrome (SIRS)
• Generalized inflammation that threatens vital organs
• Conditions that can lead to SIRS are shock, multiple
transfusions, massive tissue injury, burns, and
pancreatitis
• Effects are damage to the endothelium of blood
vessels and a hypermetabolic state
• Increases capillary permeability; allows fluid to leak into body
tissues
• Hypotension, microemboli, and shunting of blood flow
compromise organ perfusion
• The hypermetabolic state is characterized by increased
serum glucose, which eventually depletes
carbohydrate, fat, and protein stores
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Diagnosis
• Diagnosis of SIRS is made when a patient
manifests two or more of the following:
• Temperature less than 97° F (36° C) or more than
100.4° F (38° C)
• Heart rate more than 90 bpm
• Respiratory rate more than 20/min, or Paco2 less
than 32 mm Hg
• WBC count less than 4000 cells/mm3 or more than
12,000 cells/mm3, or more than 10% immature
(band) neutrophils
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SIRS Manifestations
• Range from mild to severe
• Sepsis
• A patient has SIRS with a confirmed infection
• Advanced SIRS and failure of more than one organ
• Deterioration of cardiac, pulmonary, renal, and central nervous
systems, liver, pancreas, and GI tract
• Thrombocytopenia may develop and progress to disseminated
intravascular coagulation
• If three or more organs fail, the prognosis is very poor
• Multiple organ dysfunction syndrome (MODS)
• More than one organ begins to fail
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Medical Treatment and
Nursing Interventions
• Prevent and treat infection
• Monitor potential sites; assess for signs and
symptoms
• Maintain strict asepsis with invasive procedures and
equipment
• Exercise scrupulous hand washing
• Administer antimicrobials as ordered
• Administer enteral feedings as ordered to enhance
perfusion of the GI tract
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Medical Treatment and
Nursing Interventions
• Maintain tissue oxygenation
• Administer sedatives and analgesics as ordered to
reduce oxygen requirements
• Monitor the patient on mechanical ventilation
• Administer drugs to improve cardiac output and
tissue perfusion as ordered
• Plan care to minimize physical demands on patient
• Provide nutritional and metabolic support
• Provide enteral or parenteral nutrition as ordered
• Monitor blood glucose and weight
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Medical Treatment and
Nursing Interventions
• Support failing organs
• Mechanical ventilation for respiratory distress
syndrome
• Replacement therapy for renal failure
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