Cardiac Pathophysiology

Question 1

What are the 4 different categories used to categorize shock?

Answer 1

Distributive
Obstructive
Hypovolemic
Cardiogenic

Question 2

What is the common pathology behind s/s of shock?

Answer 2

inadequate tissue perfusion

Question 3

What are compensatory mechanisms for shock?

Answer 3

Vasoconstriction, tachycardia, tachypnea, restlessness, interstitial fluid moves into capillaries, increased vasopressin, glucocorticoids, renin, aldosterone, erythropoeitin, plasma protein synthesis

Question 4

What is refractory shock?

Answer 4

shock state that persists for hours, patients do not die immediately but do not get better either, eventually have no response to vasopressor drugs or volume replacement, “irreversible shock”

Question 5

What are 3 factors that lead to refractory shock?

Answer 5

decreased cerebral perfusion
myocardial failure
pulmonary damage (ARDS)

Question 6

What is the etiology of hypovolemic shock?

Answer 6

inadequate blood volume

Question 7

What is the presentation of hypovolemic shock?

Answer 7

rapid and thready pulse, cold, pale, clammy skin, intense thirst, rapid respiration, restlessness, decreased urine output

Question 8

What are the 4 categories of hypovolemic shock?

Answer 8

hemorrhagic
traumatic
surgical
burn

Question 9

What is classified as moderate hemorrhage in someone with surgical/hemorrhagic shock?

Answer 9

5-15 mL/kg body weight

Question 10

What are some manifestations of moderate hemorrhage in hypovolemic shock?

Answer 10

Reduced pulse pressure
Normal BP initially but eventually tachycardia and hypotension
Lost plasma proteins in blood take 3-4 days for liver to synthesize
Increase in circulating erythropoietin takes 4-8 weeks to restore RBCs to normal

Question 11

What causes traumatic hypovolemic shock?

Answer 11

• damage to muscle and bone - bleeding into injured areas, more blood usually lost than meets the eye, thigh muscles can accommodate 1 L of extravasated blood with an increase in thigh diameter of only 1 cm
• Crush syndrome - when pressure is relieved from previously crushed skeletal muscles, muscles are re-perfused and free radicals are generated which cause further muscle damage which include calcium, potassium, myoglobin, and fat)

Question 12

What things can occur in someone with cardiogenic shock?

Answer 12

dysrhythmia
acute valvular dysfunction
ruptured ventricle
pump failure

Question 13

What is cardiogenic shock?

Answer 13

the pumping action of the heart is impaired to the point that tissue perfusion needs are not met

Question 14

What is surgical hemorrhagic shock?

Answer 14

combination of external hemorrhage, bleeding into tissues, and dehydration

Question 15

What is distributive shock?

Answer 15

all of the signs of shock except the skin is warm

Question 16

What is characteristic of anaphylactic shock?

Answer 16

massive peripheral vasodilation which causes warm extremities and skin

Question 17

What is neurogenic shock and what type of shock is it?

Answer 17

interruption in the transmission of autonomic activity which results in vasodilation and peripheral pooling of blood

Question 18

What are the two types of distributive shock?

Answer 18

anaphylactic shock

neurogenic shock

Question 19

What are examples of obstructive shock?

Answer 19

cardiac tamponade
massive pulmonary emboli
tension pneumothorax
pericardial disease
increase in PVR from PE or pulm HTN
cardiac tumor
obstructive valvular disease

Question 20

What is the treatment for shock?

Answer 20

treat the cause

Question 21

Do all forms of shock need volume?

Answer 21

No

Question 22

What are anesthetic implications for shock?

Answer 22

• anesthetize patient (recall occurs most often during times of hypotension and shock)
• keep patient warm
• keep normal pH