SHOCK

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• SHOCK

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SHOCK DEFINTION

• The common denominator in all forms of shock is
  inadequate capillary perfusion.
• Shock is Characterized by Inadequate Tissue
  Perfusion and Cellular Hypofunction/Hypoxia.
• Total body celular metabolism is malfunctional,
  usually by inadequate delivery of oxyden to meet
  celluar needs and occasionally of inability of
  cells to utilize oxygene( methemoglobinemia,
  carbon monooxide poisoning).

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SHOCK

• shock has been recognised for over 100 years, a
  clear definition is not estabilished till this
  moment, the definition of shock varies from time
  to time and has different meanings according to
  the etiological and pathogenetic factors, what
  caused it.

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Classified by Etiologyby Mark A. Graber,
MDDepartments of Family Medicine and Emergency
Medicine University of Iowa College of Medicine
Peer Review Status Externally Peer Reviewed by
Mosby

• Hypovolemic shock from volume loss (e.g.,
  dehydration, blood loss, burns)
• Distributive shock based on loss of vascular
  tone (e.g., anaphylactic, septic, bacteremic,
  toxic, neurogenic shock).

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Classified by Etiologyby Mark A. Graber,
MDDepartments of Family Medicine and Emergency
Medicine University of Iowa College of Medicine
Peer Review Status Externally Peer Reviewed by
Mosby

• Cardiogenic shock based on pump failure( acute
  myocardial infarction, ventricular septal defect
  rupture, papillar muscles rupture, ventricular
  aneurysm, severe aortic stenosis, arrhythmias,
  trauma- tensione pneumothorax, pericardial
  temponade, cardic contusion
• Dissociative shock based on inability of RBC to
  deliver oxygen
• (e.g., methemoglobinemia, carbon monoxide
  posoning).

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Most common clinical signs

• Hypotension. Blood pressure drop is a late
  finding.
• An orthostatic systolic decrease of 10 to 20 mm
  Hg or increase in pulse of 15 beats/min is
  considered "significant."
• Take orthostatic vital signs recumbent and after
  standing for 1 to 2 minutes. Orthostatic vital
  signs may be normal in hypovolemic individuals,
  or nor-mal individuals may exhibit orthostatic
  changes so use clinical judgment and base
  treatment on symptoms. Alcohol ingestion, a meal,
  increased age, antihypertensives, etc. may cause
  orthostatic changes in BP and pulse in the
  absence of hypovolemia.

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Most common clinical signs

• Tachycardia usually present but may not be,
  especially in the presence of diaphragmatic
  irritation, which causes vagal stimulation, in
  neurogenic shock.

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Most common clinical signs

• Hypoperfusion including decreased urine output,
  decreased mentation, cool extremities, mottling,
  etc. Goal of resuscitation is to maintain urine
  output between 30 and 60 ml/hr.

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Hypovolemic shock

• Definition
• It is present when marked reduction in oxygen
  delivery results from diminished cardiac output
  secondary to inadequate volume of whole blood.

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Hypovolemic shock

• The main causes are
• - external bleeding
• - internal bleeding
• - the loss of big amount of plasma due to wide
  burns
• - the loss of liquids and electrolytes after long
  lasting and hard diarrhea, vomiting
• - an internal loss of liquids due to pleuritis of
  peritonitis, acute pancreatitis.
• three last sometimes nemed as oligemic shock

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Hypovolemic shock

• Pathophysiology
• diminishing cardiac output or fluid flow
  secondary to decreasing venous return

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Hypovolemic shock

• Clinicla signs
• hypotensia, tachycardia, tachypnoe, oliguria,
  anxious, skin is pale and cool, often patient
  have nausea and vomiting, can be restless or
  comatose

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Hypovolemic shock acording American Surgeons
Committee of Trauma 1988
Clinical signs I class II calss III class IV class
Blood loss lt750 750-1500 1500-2000 2000gt
Blood loss lt15 15-30 30-40 40gt
Puls rate lt100 gt100 gt120 140gt
AP Normal Normal Decreased Decreased
BR 14-20 20-30 30-40 gt35
Urination(ml/h) 30gt 20-30 5-15 lt5
CNS function A litttile anxious Middle anxious Anxious or suffocating Suffocating or lethargic
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Hypovolemic shock

• Laboratory determination
• arterial blood gases pH is considered normal
  7.35-7.45, PaCO2 35-45mm/ml, in pH lt7.35 is
  associated with a normal or less normal PaCO2
  -( metabolic acidosis)
• in vomiting by stenosis of pyloric part of
  ventriculus - alcalosis
• serum electrolytes in hemorragic shock near
  normal, in diarhhoe K?, vomiting Na?,
  pancreatitis Ca? ,K? and etc.
• creatinine is usefule as an indicator of renal
  function

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Hypovolemic shock

• Treatment and menagemant of hypovolemic shock
  principles
• monitoring of blood pressure, urination, breafing
  function, HR
• replasment of blood volume ( Ringer lactate,
  solutions similar to plasma in electrolites
  composition, starch or gelatin solution, in
  bleading erythrocite mass
• supplemental oxygene
• after resuscitation surgery manipulations,
  interventionaly radiology, endoscopy, drugs.

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Distributive shock

• septic, bacteremic shock - based on loss of
  vascular tone, bacteremia and septic shock are
  closely related conditions.

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Distributive shock

• Bacteremic shock develops when hight amount of
  of bacteremia or fungs and its toxic agents
  penetrate into the blood and when the host
  defenses are decreased due to prolonged and hard
  infectional illness.

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Distributive shock

• Septic shock is sepsis with hypoperfusion and
  hypotension refractory to fluid therapy.
• When bacteremia produces changes in circulation
  such that tissue perfusion is critically reduced,
  septic shock ensues.

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Distributive shock

• The main causes are
• Septic shock is more often caused by
  hospital-acquired gram-negative bacilli and
  usually occurs in immunocompromised patients and
  those with chronic diseases.
• In about 1/3 of patients it is caused by
  gram-positive cocci and by Candida organisms.
• Shock caused by staphylococcal toxins is called
  toxic shock, a condition more frequently
  occurring in young women.

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Distributive shock

• Predisposing factors diabetes mellitus,
  cirrhosis, leukopenic states, especially those
  associated with underlying neoplasms or treatment
  with cytotoxic agents,
• antecedent infection in the urinary, biliary or
  GI tracts,
• invasive devices- catheters, drainage tubes, and
  other foreign materials and prior treatment with
  antibiotics, corticosteroids, or ventilator
  devices.

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Distributive shock

• Septic shock occurs more often in newborns,
  patients gt 35 yr, pregnant women, and those
  seriously immunocompromised by underlying
  diseases or iatrogenic complications of
  treatment.

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Distributive shock

• Pathogenesis
• The bacterial toxins generated by the infecting
  organisms trigger complex immunologic reactions
  a large number of mediators, including TNF,
  leukotrienes, lipoxygenase, histamine,
  bradykinin, serotonin, and IL-2, have been
  implicated in addition to endotoxin (the lipid
  fraction of the lipopolysaccharides released from
  the cell wall of gram-negative enteric bacilli).

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Distributive shock

• Warm shock initially, vasodilatation of
  arteries and arterioles occurs, decreasing
  peripheral arterial resistance with normal or
  increased cardiac output even though the ejection
  fraction may be decreased when heart rate
  increases.

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Distributive shock

• Cold shock later, cardiac output may decrease
  and peripheral resistance may increase. Despite
  increased cardiac output, blood flow to the
  capillary exchange vessels is impaired, and the
  delivery of vital substrates, especially O2, and
  the removal of CO2 and waste products are
  decreased. This decreased organ perfusion
  particularly affects the kidneys and brain, and
  subsequently causes failure of one or more of the
  visceral organs. Ultimately, cardiac output
  declines and the typical features of shock
  appear.

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Distributive shock

• Clinical signs
• altered mental alertness, chacking chill, rapid
  rise of body temperature, BP decreased to lt 80mm
  Hg , the skin is warm (paradoxically warm
  extremities), tachycardia, tachyon, and oliguria
• late cool, pale extremities with peripheral
  cyanosis and mottling are late signs, with
  progression, multiorgan failure involves the
  kidney, lungs, and liver disseminated
  intravascular coagulation (DIC) and heart failure
  may also occur.

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Distributive shock

• Laboratory determination
• leucocytosis, with marcet shift to left,
  associated with a sharp decrease in platelet
  count to lt 50,000/µL, respiratory alcalosis,
  metabolic acidosis, toxic anemia, positive blood
  cultures.

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Distributive shock - Managment

• should be treated in an ICU, the following
  should be monitored frequently systemic
  pressure, arterial and venous blood pH, arterial
  blood gas levels, blood lactate level, renal
  function, electrolyte levels, and possibly tissue
  PCO2, urine output should be measured, usually
  with an indwelling catheter, as an indication of
  splanchnic blood flow and visceral perfusion,

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Distributive shock - Managment

• the CVP or pulmonary artery pressure should be
  measured, and fluid replacement should be given
  until the CVP reaches 10 to 12 cm H2O or until
  the pulmonary wedge pressure reaches 12 to 15 mm
  Hg,

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Distributive shock - Managment

• respiration should be supported with nasal O2,
  tracheal intubation or tracheostomy, and
  mechanical ventilation as necessary,

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Distributive shock - Managment

• parenteral antibiotics should be given after
  specimens of blood, body fluids, and wound sites
  have been taken for Gram stain and culture
• prompt empiric therapy is essential, the choice
  of an antibiotic requires an educated guess based
  on the results of previous cultures from the site
  of the primary infection or on the clinical
  setting in which the primary infection occurred.

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Rare cases of shock

• Shock due to the hormonal insufficiency gl
  thyroydea, hipofhysis and etc. (type
  distributive shock)

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Rare cases of shock

• Neurogenic shock hypotension secondary to
  central nervous system dysfunction, it is result
  of dysruption of the sympathetic nervous system
  (type is distributive shock).
• The main causes are trauma or lumbal ane-sthesia
  due to vasomotoric disfunction paralysis. It
  results in vaso-dilatation and decresed vascular
  resistence -gt blood insufficiency in a
  circulatory system.

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Rare cases of shock

• Neurogenic shock
• The main causes are trauma or lumbal
  ane-sthesia due to vasomotoric disfunction
  paralysis. It results in vaso-dilatation and
  decresed vascular resistence -gt blood
  insufficiency in a circulatory system.

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Rare cases of shock

• Shock due to the hyperergic reactions -
  allergic reactions develope if the patients is
  hypersensitive to various antigenes (type
  distributive shock).