Shock

Question 1

Evidence of cardiovascular organ compromise

Answer 1

Cardiac index < 2.2
SBP < 90
MAP < 65

Question 2

Signs of hypoperfusion

Answer 2

Cold, clammy, mottled skin
lactate > 2
Scvo2 < 65%
Svo2 < 60%

Question 3

signs of organ dysfunction

Answer 3

encephalopathy
lethargy
confusion
urine output < 0.5 mL/kg/hr

Question 4

Blood pressure

Answer 4

CO x SVR

Question 5

Cardiac output

Answer 5

HR x SV

Question 6

Stroke volume

Answer 6

preload
intrinsic contractility
afterload

Question 7

Mean arterial pressure

Answer 7

1/3 SBP + 2/3 DBP

Question 8

Hypovolemic shock

Answer 8

inappropriately low and sudden loss of intravascular volume:
- blood loss
- GI loss
- severe dehydration
- burns

decreased volume -> decreased preload -> decreased CO
Compensation: increase in SVR

Question 9

Hypovolemic shock management

Answer 9

Replace fluids
- crystalloids
- occasionally albumin

Hemorrhage:
- replace blood (PRBCs)
- anticoagulation reversal

Question 10

Cardiogenic shock

Answer 10

LV failure (pump failure)
MI
Arrhythmia
Heart failure
Dilated cardiomyopathy

impaired emptying of left ventricle -> decreased CO -> fluid backup in pump -> preload increases
Compensation: increased SVR

Question 11

Cardiogenic shock management

Answer 11

MI:
- revascularization CABV
Arrhythmia:
- achieve sinus rhythm

Question 12

Distributive shock

Answer 12

pronounced vasodilation “vasodilatory shock”
Sepsis
anaphylaxis
neurogenic
myxedema coma (thyroid deficiency)
adrenal insufficiency
hepatic insufficiency

vasodilation -> reduced SVR -> decreased vol returning to heart -> decreased preload
Compensation: HR increase

Question 13

Obstructive shock

Answer 13

obstruction in LV preventing pushing blood out
- pulmonary embolism
- severe pulmonary hypertension
- tension pneumothorax
- pericardial tamponade

decreased LV stroke volume -> decrease in CO and tissue perfusion
preload will appear high due to obstruction
Compensation: increased SVR

Question 14

Goal MAP in shock treatment

Answer 14

> 65

Question 15

Fluid therapy

Answer 15

Crystalloids 30 mL/kg over 15-30 min then 10 mL/kg boluses

Cardiogenic shock : 100-200 mL boluses

increase SV, CO, DO2
initiate vasoactive agent when MAP remains < 65 despite fluid admin

Question 16

Vasopressors

Answer 16

Norepinephrine
Epinephrine
Dopamine
Phenylephrine
Vasopressin

Question 17

Norepinephrine

Answer 17

Alpha adrenergic agonist - increases MAP via peripheral vasoconstriction
preferred over dopamine in septic shock
- less risk of arrhythmias
- improves renal blood flow
ADE
- significant vasoconstriction

Question 18

Epinephrine

Answer 18

potent alpha and beta adrenergic agonist
Low dose -> beta effects -> inc HR, SV, and b2 vasodilation
High dose -> alpha effects
useful for anaphylactic shock
in septic shock, 2nd line after norepinephrine
ADE
- tachycardia
- arrhythmias
- cardiac ischemia
- peripheral vasodilation
- reduced renal blood flow
- hyperglycemia
- hypokalemia

Question 19

Dopamine

Answer 19

Most effective in hypotensive pts with decreased cardiac function
useful in pts with bradycardia

low dose: dopaminergic
- vasodilation of renal, mesenteric, and coronary
- increases renal blood flow, GFR, and sodium excretion

Med dose: beta adrenergic
- increase cardiac contractility and HR
- increase norepi release form nerve terminals

High dose: alpha adrenergic
- arterial vasoconstriction

ADE:
- tachycardia
- arrythmias
- peripheral vasoconstriction

Question 20

Phenylephrine

Answer 20

Alpha 1 adrenergic agonist
not recommended in septic shock unless:
- NE produces significant tachyarrhythmias
- cardiac output is high and BP is persistently low
- salvage therapy when standard therapies are ineffective
ADE
- severe vasoconstriction
- bradycardia
- myocardial ischemia

Question 21

Dobutamine

Answer 21

Inotrope - increased cardiac contractility
added to treatment of shock when cardiac output of SVO2 / SCVO2 goals have not been achieved with vasopressor therapy

often used for cardiogenic shock

Question 22

Vasopressin

Answer 22

ADH
Relative deficiency in septic shock
Dose: 0.3 U/min
should not be used as the sole vasopressor in sepsis
ADE
- cardiac and mesenteric ischemia