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40 Cards in this Set
- Front
- Back
two types of shock due to low blood flow are...
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cardiogenic and hypovolemic
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three types of shock due to maldistribution of blood flow...
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septic, anaphylactic, neurogenic
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neurogenic shock
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occurs about 30 minutes after a spinal cord injury; blood pools in the spinal cord and doesn't move to tissues where it needs to be
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absolute hypovolemia vs. relative hypovolemia
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absolute: loss of intravascular fluid volume
relative: the fluid volume moves where it doesn't need to be, but isn't gone |
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causes of absolute hypovolemia
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hemorrhage; GI loss; fistula drainage; diabetes insipidus; hyperglycemia; diuresis
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causes of relative hypovolemia
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3rd spacing (ascites, edema, etc)
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clinical manifestations of hypovolemic shock
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anxiety; tachypnea; increase in CO, HR; decrease in SV, PAWP, UO
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PAWP
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pulmonary arterial wedge pressure; measured with a catheter wedged into the distal pulmonary artery; used to measure mean left atrial pressure
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if loss is greater than __%, blood volume must be replaced
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30
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hypotension is defined as
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a SBP of less than 90 or a reduction of more than 40 from baseline and in which BP is not adequate for normal perfusion
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what are the 4 stages of shock?
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1. initial
2. compensatory 3. progressive 4. refractory |
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initial stage of shock
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usually not clinically apparent; metabolism changes from aerobic to anaerobic-- lactic acid accumulates and must be removed by blood and broken down by liver; process requires O2 that is unavailable
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compensatory stage of shock
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clinically apparent; hopefully, patient's body is able to compensate on its own or clinically; if not, patient moves on to progressive stage.
Baroreceptors in carotid and aortic bodies activate SNS in response to lowered BP--vasoconstriction while blood to vital organs is maintained; the decrease of blood to kidneys activates the renin-angiotensin-aldosterone system to increase venous return to the heart, CO, BP; GI motility is impaired; cool, clammy skin (except septic patient who is warm and flushed); arterial O2 levels decrease, rate and depth of respirations are increased; the SNS stimulation increases myocardium O2 demands; if perfusion deficit is corrected, patient recovers with no residual sequelae |
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progressive stage of shock
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begins when compensatory mechanisms fail; capillary permeability INCREASES and fluid leaks into places it shouldn't-- protein in particular, which leads to systemic interstitial edema (anasarca); blood flow to pulmonary capillaries DECREASES and to other solid organs/peripheral tissues; PULMONARY EDEMA; BRONCHOCONSTRICTION; fluid moves into alveoli, causing edema and decreased SURFACTANT; TACHYPNEA, CRACKLES, INCREASED WORK OF BREATHING; CO begins to fall, hypotension, weak peripheral pulses; ischemia of distal extremities; dysrhythmias, MI, complete deterioration of CV system; mucosal barrier of GI system becomes ischemic--ULCERS AND BLEEDING; risk of translocation of bacteria, decreased ability to absorb nutrients, "DEAD GUT"; liver fails to metabolize drugs and wastes----> JAUNDICE; elevated enzymes, loss of immune function, risk for significant bleeding---> acute tubular necrosis/ acute renal failure
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what happens to potassium levels during the progressive stage of shock?
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increases
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refractory stage of shock
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exacerbation of anaerobic metabolism; accumulation of lactic acid; increased capillary permeability; profound hypotension and hypoxemia; tachycardia worsens; decreased coronary blood flow; CEREBRAL ISCHEMIA; failure of one organ system affects others, and recovery is unlikely; severe hypotension (SBP < 80); very rapid, weak pulse; rapid, shallow respirations with crackles and wheezes; cool, pale skin, mottled with cyanosis; disoriented; lethargic; comatose; ANURIA; loss of reflexes; decreased or absent pulses
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what sort of therapy is used for septic, hypovolemic, and anaphylactic shock?
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volume expansion; isotonic crystalloids (ie normal saline) for initial resuscitation of shock
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what do you do if patient does not respond to 2 to 3 L of crystalloids?
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blood administration and central venous monitoring
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complications of fluid resuscitation
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hypothermia; coagulopathy
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nutrition that is given to decrease morbidity from shock
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initiate enteral nutrition within the first 24 hours; initiate parenteral nutrition if enteral feedings are contraindicated or fail to meet at least 80% of the caloric requirements
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what is normal urinary output in ml/kg/hr
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>0.5 ml/kg/hr
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hormones released in response to low BP
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ADH, renin, epinephrine, aldosterone
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how long can kidneys tolerate hypoxia and anoxia without damage?
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one hour
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cellular death liberates what ion
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potassium
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urine specific gravity remains at what level when kidneys fail
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1.010
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shock is characterized by
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impaired oxygen and nutrient exchange
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what is a common feature of various types of shock?
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physiologic response
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which lab result would you monitor while administering Ringer's Lactate intravenously during shock resuscitation?
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lactate, because the liver is unable to convert it
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which lab test reveals nutritional status accurately?
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serum protein
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what happens to blood glucose levels during the compensatory state of shock?
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increases due to SNS stimulation
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what happens to blood glucose levels during the refractory period of shock?
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decreases
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daily weights during shock management are done to measure what?
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fluid status
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nutritional therapy is begun early in shock management to...
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enhance GI perfusion
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more causes of relative hypovolemia
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bowel obstruction (thus pooling of blood or fluids); burns; internal bleeding (ie fracture of long bones, ruptured spleen, hemothorax, severe pancreatitis; massive vasodilation (ie sepsis)
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what happens to urine specific gravity during hypovolemic shock?
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increases
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a patient may compensate himself/herself for up to how much of total blood volume?
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15%
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at what point of fluid loss do SNS changes begin to occur?
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15-30%
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at what point of fluid loss do the compensatory mechanisms begin to fail, causing the necessity for immediate replacement with blood or blood products?
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30% or more
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the rule for fluid resuscitation during hypovolemic shock?
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3:1 (3 ml of isotonic crystalloid for every 1 ml of estimated blood loss)
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overall goals for patient in shock
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1. assurance of adequate tissue perfusion
2. restoration of normal/baseline BP 3. return/recovery of organ function 4. avoidance of complications from prolonged states of hypoperfusion |