Pathophysiology and Therapy of Shock

Question 1

what are the classic signs of shock?

Answer 1

tachycardia and increased pulse rate
tachypnea
pale and cool skin
mucous membrane pallor
delayed capillary refill time
reduced urine output
weak arterial pulses, abnormal pulse pressure
muscle weakness
pupillary dilation abnormal sensorium

Question 2

what is the definition of shock?

Answer 2

clinical syndrome resulting when cardiac output is insufficient to fill the arterial tree with blood under sufficient pressure to provide organs and tissues with adequate blood flow
oxygen deficit to tissues

Question 3

what characterizes shock?

Answer 3

reduced tissue perfusion
impaired oxygen delivery
inadequate cellular oxygen utilization
inadequate cellular energy production

Question 4

what are the major mechanisms for lack of oxygen delivery/utilization to tissues (shock)?

Answer 4

inadequate blood volume
inadequate cardiac performance
inadequate vascular tone
tissue defect in oxygen utilization

Question 5

what does higher sympathetic tone lead to?

Answer 5

faster heart rate
positive inotropy
positive chronotropy
increased vascular tone

Question 6

what are some etiologies of shock?

Answer 6

hemorrhage/hypovolemic
traumatic
cardiogenic
septic
neurogenic
anaphylactic

Question 7

what are the compensatory mechanisms from the sympathetic nervous system in shock?

Answer 7

increased heart rate
increased inotropy
vasoconstriction
increase blood pressure towards normal
hepatic glycogenolysis to increase blood glucose

Question 8

what does the baroreceptor response in shock lead to?

Answer 8

increased cardiac output

Question 9

what happens with the blood due to reduced cardiac output?

Answer 9

metabolic acidosis
elevated blood lactate

Question 10

what do cats usually have in response to shock/critical illness?

Answer 10

bradycardia
hypothermia
hypoglycemia

Question 11

what often happens in cardiogenic shock?

Answer 11

fluid volume typically excessive
ANP and BNP are elevated
jugular vein is distended

Question 12

what is infection?

Answer 12

inflammatory response to the presence of microorganisms

Question 13

what is endotoxemia?

Answer 13

endotoxin in the bloodstream

Question 14

are fluids or diuretics indicated in cardiogenic shock?

Answer 14

diuretics often indicated
fluids often not indicated

Question 15

what is septic shock?

Answer 15

severe sepsis with hypotension that is unresponsive to adequate fluid resuscitation

Question 16

what criteria does an animal have to have 2/3 of to have systemic inflammatory response syndrome (SIRS)?

Answer 16

abnormal temperature
abnormal heart rate
tachypnea
leukocytosis, leukopenia, or significant left shift

Question 17

what is multiple organ dysfunction syndrome (MODS)?

Answer 17

presence of organ dysfunction in 2 or more systems

Question 18

how is cardiovascular dysfunction identified?

Answer 18

need for pressors

Question 19

what is hypovolemic shock?

Answer 19

loss of circulating blood volume

Question 20

what can cause hypovolemic shock?

Answer 20

hemorrhage
gastrointestinal losses
reduced intake of fluids
diuresis
third spacing of fluids
addison’s disease

Question 21

what should you do after giving sufficient fluids if shock persists?

Answer 21

give pressors or inotropes

Question 22

what is a shock dose of fluids for a dog and cat?

Answer 22

dog: 90 ml/kg in an hour
cat: 60 ml/kg in an hour

Question 23

how should you bolus a dog with crystalloids in shock?

Answer 23

give bolus of 20 ml/kg, then reassess
repeat up to 3 times (80 ml/kg) then think about pressors, blood, colloids

Question 24

what are the replacement fluid types?

Answer 24

0.9% NaCl
lactated ringer’s solution
plasmalyte A

Question 25

do crystalloids stay in the intravascular space for long?

Answer 25

no

Question 26

what is hypertonic saline used for?

Answer 26

very large animals head trauma cases to minimize cerebral edema maybe large breed dogs

Question 27

what are some potential side effects of hypertonic saline?

Answer 27

hyperosmolarity hemolysis hypernatremia hyperchloremia hypotension or ventricular premature contractions if given too fast

Question 28

what are colloids?

Answer 28

large, oncotically active particles

Question 29

what do colloids maintain?

Answer 29

intravascular colloid osmotic pressure

Question 30

how well do colloids persist in the intravascular space?

Answer 30

better than crystalloids

Question 31

what is the total dose of colloids?

Answer 31

20 ml/kg often 5 ml/kg boluses

Question 32

why might you give fresh frozen plasma?

Answer 32

clotting factors protein

Question 33

what is cryoprecipitate?

Answer 33

clotting factors without the volume

Question 34

what makes up frozen plasma?

Answer 34

protein

Question 35

when might you use inotropes and vasopressors?

Answer 35

blood volume okay, heart or vascular tone abnormal

Question 36

what is the main inotrope/vasopressor?

Answer 36

norepinephrine

Question 37

what do beta-2 receptors stimulate?

Answer 37

vascular and bronchial receptors: vasodilation and bronchodilation

Question 38

what do alpha-1 receptors stimulate?

Answer 38

vasoconstriction and increased blood pressure

Question 39

when might colloids be used?

Answer 39

albumin dropping lower than 1.8-2.2 dropping total solids and bleeding without coagulopathy capillary leak

Question 40

what can happen with fluid overload?

Answer 40

fluid retention in lungs peripheral fluid retention associated with worse outcome

Question 41

what is cardiogenic shock?

Answer 41

low cardiac output resulting from poor cardiac performance

Question 42

what is included in the definition of cardiogenic shock?

Answer 42

low cardiac output hypotension signs of hypoperfusion normal or elevated cardiac filling pressures due to cardiac cause

Question 43

how can you treat cardiogenic shock?

Answer 43

oxygen determine and remove inciting cause

Question 44

how difficult is septic shock to treat?

Answer 44

one of most difficult forms of shock to treat

Question 45

what characterizes warm or hyperdynamic shock?

Answer 45

tachycardia bounding pulses fever hyperglycemia injected mucous membranes fast capillary refill time

Question 46

what are some complicating developments of septic shock?

Answer 46

inadequate circulating blood volume poor left ventricle contractile function loss of vasomotor tone metabolic alterations leading to reduced ability of cells to utilize oxygen

Question 47

when should you initiate antibiotics with septic shock?

Answer 47

within one hour of diagnosis delayed initiation reduces survival

Question 48

what mediates release of substances from mast cells and basophils in anaphylactic shock?

Answer 48

IgE

Question 49

what is anaphylaxis in dogs often associated with?

Answer 49

spontaneous abdominal effusion +/- gall bladder edema

Question 50

how can you treat anaphylactic shock?

Answer 50

epinephrine oxygen IV crystalloid fluid bolus re-evaluate vitals plus PCV, TS, lactate

Question 51

what is neurogenic shock?

Answer 51

loss of vasomotor tone increased vascular capacity leads to pooling

Question 52

what are some causes of neurogenic shock?

Answer 52

anesthesia too deep CNS disease trauma ischemia to vasomotor centers

Question 53

what is the equation for oxygen delivery?

Answer 53

DO2= CO x CaO2 CaO2= oxygen content of arterial blood

Question 54

what affects stroke volume?

Answer 54

preload afterload myocardial contractility

Question 55

what does the cerebral ischemic response lead to?

Answer 55

vasoconstriction via sympathetic nervous system

Question 56

what does reticuloendothelial cell depression from reduced cardiac output lead to?

Answer 56

liver/spleen cannot clear endotoxin and bacteria

Question 57

what inflammatory cytokines are released during reduced cardiac output?

Answer 57

tumor necrosis factor interleukin I platelet activating factor other cytokines

Question 58

what systems can be involved in multiple organ dysfunction syndrome (must have two or more)?

Answer 58

kidneys cardiovascular respiratory hepatic coagulation

Question 59

what does a 10% loss of circulating blood volume lead to?

Answer 59

little change in mean arterial pressure

Question 60

what is the dose of hypertonic saline?

Answer 60

4 ml/kg over more than 10 minutes

Question 61

what are some colloids?

Answer 61

hetastarch dextrans gelatin albumin hemoglobin-based oxygen carriers

Question 62

what are some disadvantages of colloids?

Answer 62

more expensive possible renal toxicity coagulopathy anaphylactic reactions not cleared quickly no clear survival benefit reduced survival in human trauma cases

Question 63

what is gram negative septic shock like?

Answer 63

various bacterial toxins plus endotoxin

Question 64

when might you give steroids in septic shock?

Answer 64

if dependent on vasopressors

Question 65

what is perhaps the most effective treatment for head trauma?

Answer 65

insure adequate blood pressure

Question 66

what are the etiologies of shock?

Answer 66

hemorrhagic/hypovolemic traumatic cardiogenic septic neurogenic anaphylactic

Question 67

what does antidiuretic hormone release lead to?

Answer 67

water retention vasoconstriction to raise blood pressure

Question 68

what does reduced gastrointestinal perfusion lead to?

Answer 68

bacterial translocation

Question 69

what does vasodilator release lead to in shock?

Answer 69

circulatory pooling and loss of effective circulating volume

Question 70

what is myocardial failure in reduced cardiac output from?

Answer 70

cytokines coronary thrombosis low cardiac perfusion

Question 71

what is severe sepsis?

Answer 71

sepsis with organ dysfunction and hypoperfusion

Question 72

what does a loss of 15-20% of the circulating blood volume lead to?

Answer 72

MAP low normal 80-90 mmHg spontaneous recovery possible

Question 73

what is an adverse reaction to crystalloids?

Answer 73

fluid overload if give too much

Question 74

how much of the administered volume of crystalloids remains in the intravascular space after an hour?

Answer 74

1/4 to 1/5 of administered volume

Question 75

will the effects of hypertonic saline persist if they are not followed by crystalloids?

Answer 75

no

Question 76

what is cryoprecipitate?

Answer 76

clotting factors without the volume of plasma

Question 77

what are some inotropes and vasopressors?

Answer 77

dopamine dobutamine norepinephrine phenylephrine milrinone or inamrinone

Question 78

what do beta 1 agonists stimulate?

Answer 78

cardiac receptors: increase heart rate and contractility

Question 79

what do beta 2 agonists stimulate?

Answer 79

vascular and bronchial receptors: vasodilation and bronchodilation

Question 80

what do alpha 1 receptors stimulate?

Answer 80

vascular receptors: vasoconstriction and increased blood pressure

Question 81

what can result in cardiogenic shock?

Answer 81

cardiac tamponade due to pericardial effusion ruptured chordae tendinae severe arrhythmia myocardial infarction pulmonary thromboembolism tension pneumothorax

Question 82

what is gram positive shock like?

Answer 82

various bacterial toxins

Question 83

when might you see bradycardia with neurogenic shock?

Answer 83

elevated intracranial pressure

Question 84

what is the treatment of neurogenic shock?

Answer 84

oxygen crystalloid fluid bolus reduce anesthesia level consider vasopressors early

Question 85

how can you treat head trauma in neurogenic shock?

Answer 85

insure adequate blood pressure surgical decompression if indicated mannitol if not hypovolemic diuretic is not hypovolemic