shock ch. 39

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shock ch. 39
2013-03-10 13:42:58

ch. 39
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  1. shock
    widespread abnormal cellular metabolism that occurs when oxygenation and tissue perfusion needs are not met to the level necessary to maintain cell function

    "syndrome" because cellular, tissue and organ events occur in a predictable sequence.
  2. different types of shock
    hypovolemic- when too little circulating blood volume causes a MAP decrease resulting in inadequate total body oxygenation (hemorrhage and dilation)

    cardiogenic-when actual heart muscle is unhealthy and pumping is directly impaired.

    distributive-when blood volume is not lost from the body but is distributed to the interstitial tissues where it cannot circulate and deliver oxygen.

    neural distributive-loss of MAP that occurs when sympathetic nerve impulses controlling blood vessel smooth muscle are decreased and the smooth muscles relax, causing vasodilation.

    chemical induced distributive- three common origins (anaphylaxis, sepsis, cap. leak syndrome)

    obstructive- causes by problems that impair the ability of the normal heart muscle to pump effectively.

    -more than one type of shock can be present at one time
  3. MAP
    tissue perfusion and organ perfusion depend on:

    • -total blood volume
    • -cardiac output
    • -size of the vascular bed
  4. vascular bed and MAP
    increase in vascular bed lower MAP and decreases raise MAP
  5. sympathetic tone
    when nerves continuously stimulate vascular smooth muscle so that the blood vessels are normally partially constriced
  6. increase in sympathetic tone
    constrict smooth muscle raising MAP
  7. decrease in sympathetic tone
    relax smooth muscle, dilating blood vessels and lower MAP
  8. exogenous
    originate outside the body
  9. endogenous
    induced by substances normally found in the body

    ex: excessive amounts of histamine
  10. anaphylaxis
    result of type 1 allergic reactions

    -results in widespread loss of blood vessel tone and decreased cardiac output
  11. sepsis
    widespread infection that triggers a whole body inflammatory response

    -leads to distributive shock when infectious microorganisms are present in the blood

    -most commonly called septic shock
  12. capillary leak syndrome
    the response of capillaries to the presence of biologic mediators that change the blood vessel integrity and allow fluid to shift from the blood vessels into the interstitial tissues.

    once in the interstitial tissues these fluids are stagnant and cannot deliver oxygen or remove tissue waste products
  13. anaerobic cellular metabolism
    metabolism without oxygen
  14. pathophysiology
    -decreased blood volume leading to decreased mean arteriole pressure (MAP)

    -loss of oxygen transport to tissues leading to anaerobic metabolism

    -baroreceptors (pressure sensitive): decrease of MAP 5-10 mm hg below base line. in the aortic and carotid sinus.

    -SOSĀ  to brain


    -shunting: movement of oxygenated blood into selected areas while bypassing others results in some shock manifestations
  15. stages of shock (initial stage)
    • -decrease in baseline mean arterial pressure MAP of 5-10 mm hg
    • -normal oxygenation to body organs
    • -cellular changes
    • -increased sympathetic stimulation
    • -mild vasoconstriction
    • -overall metabolism is aerobic
    • -slight lactic acid levels increase (bad)
    • -SUBTLE changes in VS
    • -increased heart rate, RR, minimal diastolic BP

    VOL. LOSS=15% OR 750 MLS
  16. nonprogressive/compensatory stage
    • -decrease in MAP of 10-15 mm hg from the patients baseline value
    • -continued sympathetic stimulation
    • -moderate vasoconstriction
    • -increased HR
    • -decreased pulse pressure
    • -kidneys and baroreceptors react
    • -tissue hypoxia
    • -non vital organs
    • -anaerobic metabolism changes
    • -decrease in PH
    • -increase in K+
    • -chemical manifestations: renin, aldosterone, antidiuretic hormone secretion
    • -increased vasoconstriction, decreased urine output, stimulation of thirst reflex
    • -mild acidosis, mile hyperkalemia
    • -restless, tachycardic, increase resp. rate, systolic decrease, diastolic increase, o2 decrease, cool extremities

    VOL. LOSS=15-30% OR 750-1500 MLS
  17. progressive/intermediate stage
    • -sustained decrease in MAP more than 20 mm hg (doesnt come back)
    • -compensatory mechanisms ineffective
    • -hypoxia (low o2)-vital organs
    • -anoxia (no o2)-non vital organs
    • -ischemia
    • -decreased blood PH and increase in lactic acid level
    • -overall metabolism is anaerobic
    • -moderate acidosis, moderate hyperkalemia, tissue ischemia
    • -rapid, weak pulse, low blood pressure, pallor or cyanosis of oral mucosa and nail beds, cool moist skin, anuria, 5-20% decrease in o2 sat.


    VOL. LOSS=30-40% OR 1500-2000 MLS
  18. refractory/irreversible stage
    • -severe tissue hypoxia with ischemia and necrosis
    • -release of myocardial depressant factor from the pancreas
    • -build up of toxic metabolites
    • -multiple organ dysfunction (MOD)
    • -systemic hypo-perfusion
    • -unresponsive to therapy
    • -end organ damage
    • -DEATH

    VOL. LOSS=MORE THAN 2000 OR 40%
  19. MODS
    • multiple organ dysfunction syndrome
    • -sequence of cell damage caused by massive release of toxic metabolites and enzymes
  20. history
    • -symptoms
    • -recent illness/procedures
    • -mechanism of injury
    • -chronic conditions
    • -pain location
    • -vomiting
    • -decreased urine output
    • -gynecologic problems
    • -motrin/aspirin
    • -alcohol
    • -blood thinning meds
    • -coagyopathy probs?
  21. stroke vol
    amount of blood pumped out from the heart
  22. laboratory assessment
    -ph (arterial): 7.35-7.45 decreased, insufficient tissue oxygenation causing anaerobic metabolism and acidosis

    -pao2: 80-100 decreased, anaerobic metabolism

    -paco2: 35-45 increased anaerobic metabolism

    -lactic acid 3-7 or 0.3-0.8 increased, fluid shift, dehydration

    -hematocrit females :37-47% males 42-52% increased, fluid shift, dehydration

    -hemoglobin females: 12-16 males: 14-18 increased, fluid shift, dehydration

    -potassium 3.5-5.0 increased, dehydration, acidosis
  23. drug therapy
    vasoconstrictors: dopamine, norepinephrine, phenylephrine

    inotropic agents: dobutamine. milrinone

    enhancing myocardial perfusion: sodium nitroprusside