Lec 30 Shock Flashcards

1
Q

What is definition of shock?

A

inadequate organ perfusion to meet tissue’s oxygenation demand

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2
Q

What is the definition of hypotension?

A

transient fall in BP

  • systolic BP < 90 OR mean arterial P < 60 OR decrease in systolic BP > 40 mmHg from pts baseline
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3
Q

What is pathophysiology of shock?

A

ATP + H2O –> ADP + Pi + H

  • lack of ATP production –> Na/K failure
    anaerobic metabolism –> accumulation of acid –> metabolic acidosis
  • cell swelling leading to rupture + death
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4
Q

Why do we monitor pt undergoing shock?

A
  • to understand their disease
  • to describe pts physiologic status
  • facilitate diagnosis and treatment of shock

b/c shock cna change rapidly

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5
Q

When do you use pulm artery catheter with shock?

A
  • to get index of volume status [normal central venous pressure = normal volume] and cardiac status [calculate CO/CI]
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6
Q

How can you use ultrasound to measure volume status?

A

if SVC not collapsed means there is sufficient volume status

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7
Q

Why might you not do swan gans catheter on ever pt who comes in with shock?

A

can cause trauma/complications

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8
Q

What does SVI tell you?

A

stroke volume index = stroke volume / body mass

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9
Q

What does LV stroke work index tell you?

A

measure of cardiac contractility

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10
Q

What is equation for systemic vascular resistance index?

A

SVRI = [MAP- CVP] / CI * 80

increases with vasoconstriction, decreases with vasodilation

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11
Q

What is equation for pulmonary vascular resistance index?

A

PVRI = [MPAP - PWAP] / CI * 80

increases with constriction, PE, hypoxia

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12
Q

Lung circuit resistance affects which part of heart function? what about systemic circuit resistance?

A

pulm circuit resistance affects RV function

systemic circuit resistance affects LV function

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13
Q

What is equation for vascular resistance?

A

vascular resistance = change in pressure / blood flow

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14
Q

What is definition of O2 delivery?

A

volume of gaseous O2 delivered to LV per min

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15
Q

What is the definition of O2 consumption?

A

volume of gaseous O2 which is actually used by the tissue per min

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16
Q

What is definition of O2 demand?

A

volume of O2 actually needed by tissues to function in an aerobic manner

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17
Q

What happens if O2 demand > consumption?

A

anaerobic metabolism

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18
Q

What are 3 signs of organ hypo-perfusion?

A
  • mental status changes = obtunded b/c lack of perfusion to brain
  • oliguria = lack of kidney perfusion
  • lactic acidosis
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19
Q

What are the 4 categories of shock?

A
  • hypovolemic
  • cardiogenic
  • distributive
  • obstructive
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20
Q

What are the goals of shock resuscitation?

A

restore BP
normalize systemic perfusion
preserve organ function

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21
Q

What are some causes of hypovolemic shock?

A
  • hemorrhage
  • vomiting
  • diarrhea
  • dehydration
  • burns
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22
Q

What is hypovolemic shock? What happens to CO/SVR/venous return/PAWP?

step1

A
  • shock related to loss of fluid

signs:
- decrease CO, decrease venous return, increase SVR

  • decrease PAWP [indicates reduced diastolic filling pressure]
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23
Q

What is the first sign of shock?

step1

A

tachycardia

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24
Q

What usually causes shock in setting of disseminated intravascular coagulation secondary to trauma?

step1

A

usually due to sepsis

25
Q

What is treatment for hypovolemic shock?

A

main treatment = give fluid

might need to use pressors transiently

26
Q

When do give crystalloids vs colloids vs fresh frozen plasma in hypovolemic shock treatment?

A
crystalloids = cheaper
colloids = give if mostly blood loss but have no actual survival benefit over crystalloids

give blood to supplement either

give fresh frozen plasma [FFP] if underlying bleeding disorder caused the loss

27
Q

What do you need to watch out for when you infuse pt with large volumes NaCl?

A

watch for hyperchloremic metabolic acidosis

28
Q

What is cardiogenic shock? signs [CO, SVR, PAWP, venous return, left ventricular stroke work]?

step1

A

cardiogenic shock is shock due to defect in cardiac function

heart failing –> can’t pump –> elevated filling pressure

signs:

  • decrease CO
  • increase SVR
  • increase PAWP
  • decrease venous return
  • decrease left ventricular stroke work = less contractility of heart
29
Q

What is PAWP a stand-in for when we are talking about shock?

step1

A

PAWP = LA pressure = diastolic filling pressure

increases when heart is failing

decreases when less volume to fill up

30
Q

What is equation for coronary perfusion pressure?

step1

A

coronary PP = DBP - PAWP = diastolic BP - filling pressure

31
Q

What is goal for coronary perfusion pressure needed to maintain?

A

coronary PP > 50 mmHg

32
Q

What treatment for cardiogenic shock?

A
  • goal is to improve myocardial function
  • fluids first then cautious pressors

remember aortic diastolic BP pressure drives coronary perfusion

if inotropes and vasopressors fail –> do intra-aortic balloon pump = increases diastolic BP so increased gradient

33
Q

What are the 4 types of distributive shock?

step1

A
  • sepsis
  • anaphylactic
  • acute adrenal insufficiency
  • neurogenic
34
Q

What happens to CO/SVR/venous return/PCWP in distributive shock?

A
  • variable CO [increase according to 1st aid]
  • variable PAOP [decrease according to 1st aid]
  • decrease SVR
  • increased venous return
35
Q

In what types of shock can you restore BP with IV fluids?

step1

A
  • in hypovolemic/cardiogenic shock

- not in distributive [septic/neurogenic/anaphylactic] shock

36
Q

What type of shock does pt appear cold, clammy b/c of vasoconstriction?

A

hypovolemic/cardiogenic

37
Q

What type of shock does pt appear warm, dry because of vasodilation?

A

distributive shock [septic, neurogenic, anaphylactic]

38
Q

What happens to body in distributive shock?

A

systemic inflammatory response syndrome

39
Q

How do you treat pt with distributive shock?

A
  • volume replacement
  • early antibiotic administration if sepsis
  • steroid if bee sting
  • inotrope [dopamine]
  • if low MAP < 60 –> give dopamine and norepinephrine
40
Q

How do you treat sepsis?

A
  • give fluids
  • correct the cause: antibiotics, debridement
  • vasopressors: phenylephrine, norepinephrine
41
Q

What causes adrenal crisis distributive shock?

A
  • autoimmune adrenalitis or adrenal apoplexy [hemorrhage or infarct of adrenal]
42
Q

How do treat ddrenal crisis distributive shock?

A

give steroids and take care of adrenal crisis

43
Q

What are some causes of obstructive shock?

A
  • cardiac tamponade
  • tension pneumothorax
  • massive PE
44
Q

What are signs of obstructive shock [to CO, PAWP, SVR]?

A
  • decrease CO
  • increase PAWP
  • increase SVR

looks like cardiogenic shock

45
Q

What happens to PAWP, CO, SVR in hypovolemic shock?

A
  • decrease PAWP
  • decrease CO
  • increase SVR
46
Q

What happens to PAWP, CO, SVR in cardiogenic shock?

A
  • increase PAWP
  • decrease CO
  • increase SVR
47
Q

What happens to PAWP, CO, SVR in distributive shock?

A
  • decrease PAWP or no change
  • CO variable
  • decrease SVR
48
Q

What happens to PAWP, CO, SVR in obstructive shock?

A
  • increase PAWP
  • decrease CO
  • increase SVR
49
Q

Why use vasopressors in shock? Possible complications? Who should you avoid using it in?

A
  • to increase contractility
  • but need preload first so only give pressor after you give fluids
  • risk tachycardia and increase myocardial O2 consumption if used too soon
  • don’t use in post-MI shock pt
50
Q

What types of vasopressors could you use in shock?

A

dopamine
dobutamine
norepinephrine
epinephrine

51
Q

What is effect of dopamine low dose? moderate/ high? side effects?

A

low dose = acts on dopaminergic receptors
moderate dose = B effects –> contractility
high dose = a-effects –> vasoconstriction

52
Q

What is effect of dobutamine? when should you caution use?

A

selective B agonist
potent inotrope = increase contractiliy + stroke work

caution in hypotension [may preciptate tachycardia or worsen hypotension]

53
Q

What is action of norepinephrine?

A
  • mostly a agonist = vasopressor
  • also some B agonist = inotrope, chronotrope

large doses may cause lactic acidosis

54
Q

What is action of epinephrine?

A
  • a and B adrenergic effects
  • potent inotrope and chronotrope
  • increases myocardial oxygen consumption particularly in coronary heart disease
55
Q

What is treatment of choice for distributive shock?

A

epinephrine = epi pen

56
Q

What is action of amrinone?

A

phosphodiesterase inhibitor
positive inotrope + vasodilation

increases CO without an increase in cardiac stroke work

second line after dobutamine

57
Q

24 year old male victim of a shotgun blast to his right lower quadrant/groin at close range.

Hemodynamically unstable in the field and his right lower extremity was cool and pulseless upon arrival to the trauma resuscitation area.

Patient received 12 L crystalloid, 15 units of blood, 6 units of FFP, and 2 6 packs of platelets.
HR 130, BP 96/48, T 34.7° C
PAWP 4, CVP 2, CI 2.2, SVRI 2700,

Diagnosis? Treatment?

A

LOW PAWP/CVP/CI + HIGH SVR
== hypovolemic shock

give volume/fluids

58
Q

68 year old female restrained driver who was involved in a high speed MVC.

She sustained a pulmonary contusion and fractured pelvis.

Intubated and monitored with PA-C
PCWP = 22, CI = 2.5, SVRI = 2800,
HR = 120, BP = 110/56, SpO2 = 91, urine output is reduced

What do you think…

A

high SVR and HR, normal BP, low urine output, high PAWP

think cardiogenic or obstructive

next step = do echo and figure out whats going on with the heart