7. Embolic Events- Exam 2

Question 1

What is the incidence of clinically obvious strokes post CPB

Answer 1

1-5%

Question 2

MRI suggests that there could be new infarcts in what % of those same patients

Answer 2

30%

Question 3

is the source of strokes necessarily from CPB

Answer 3

nope

-patients are a major contributor

Question 4

what % of CABG patients experienced cerebral infarct prior to surgery

Answer 4

50%

Question 5

what are the 3 types of infection

Answer 5

1. Biologic (bloodborne)
2. Foreign Material (Circuit/Manufacturing)
3. Gaseous

Question 6

Micro vessels are the main target for emboli. What are their diameter

Answer 6

3-500 micrometers in diameter

Question 7

what is the greatest period of risk for emboli

Answer 7

1. Insertion of arterial cannula
2. Initiation of bypass (hypotension)
3. Cross-clamp application/removal
4. Use of centrifugal pump (any time you have a decrease in flow)

Question 8

trauma to the aorta can contribute to brain infarctions for how long

Answer 8

up to 1 month

Question 9

what organ is at the greatest risk for emboli

Answer 9

brain

Question 10

Formation of biologic emboli: homologous transfused blood- risk increases with what

Answer 10

storage time

Question 11

Formation of biologic emboli: inadequate anticoagulation with contact with what

Answer 11

foreign surface

Question 12

Formation of biologic emboli: areas at risk from inadequate anticoagulation-contact with foreign surface

Answer 12

minimal flow
stagnant areas
turbulence
cavitation
rough areas

Question 13

Formation of biologic emboli: areas of the circuit at risk from inadequate anticoagulation-contact with foreign surface

Answer 13

connectors
bubble oxygenators
ALF
cardiotomy rservoirs
intraluminal projections

Question 14

Formation of biologic emboli: Trauma to ____ cells of epicardium and trauma to ____ of the surgical wound

Answer 14

fat

tissue

Question 15

Formation of biologic emboli: do you need CPB to produce fat emboli? what other sources are there?

Answer 15

No
Median sternotomy
Thoracotomy

Question 16

Formation of biologic emboli: how much fat within a circuit comes from cardiotomy suction

Answer 16

2/3

Question 17

Formation of biologic emboli: fat emboli can be large particles of how many microns

Answer 17

4 - 200 microns

Question 18

Formation of biologic emboli: what organs can fat emboli be found in post bypass

Answer 18

kidney
lungs
heart
brain
liver
spleen

Question 19

Formation of biologic emboli: complement activation sue to what

Answer 19

surface contact- activation process

Question 20

Formation of biologic emboli: complement activation from surface contact includes what

Answer 20

platelets and neutrophils

Question 21

platelet counts drop what % with initiation of bypass

Answer 21

30-50%

-also drop in # of functional platelets

Question 22

describe platelets role with decreased #

Answer 22

post-op bleeding
neurologic dysfunction
release of histamine (membrane permeability)
release of serotonin/thromboxane (vasoconstriction)

Question 23

name some examples of foreign particle emboli

Answer 23

cotton fibers
plastic particles
 filter material
spallation
bone wax

Question 24

name 4 sources of gaseous microemboli

Answer 24

bubble oxygenators
temp gradients
surgical air
pump/circuit problems

Question 25

bubble oxygenators can produce what size emboli thats associated with CPB mortality and morbidity

Answer 25

35 - 40 micrometers - mainly oxygen - solution was to transition to membrane oxygenators

Question 26

name 3 ways to create surgical air

Answer 26

1. heart contracts before chambers are completely de-aired 2. surgeon cuts into chamber of beating heart 3. placement of arterial, venous or LV vent cannulae

Question 27

how long is surgical air present in the heart post CPB

Answer 27

30 to 40 min

Question 28

what is a solution to correct surgical air

Answer 28

flush with CO2... 86% of buubles gone within 1 minute

Question 29

name 5 ways to pump air

Answer 29

1. inattention to level in VR 2. reversed roller pump 3. retrograde flow through centrifugal pumo 4. drug injections into circuit 5. inadequate debubbling of ALF - --more on slide 15

Question 30

what % of air is pumped due to inattention to VR level

Answer 30

37%

Question 31

what % of air is pumped due to aortic root air during plegia administration

Answer 31

29%

Question 32

what % of air is pumped due to unexpected heart beat

Answer 32

10%

Question 33

what % of air is pumped due to reversed LV vent line

Answer 33

9%

Question 34

what % of air is pumped due to pressurized cardiotomy

Answer 34

5%

Question 35

what % of air is pumped due to ruptures arterial pumphead tubing

Answer 35

5%

Question 36

what % of air is pumped due to unnoticed rotation of arterial pump head

Answer 36

5%

Question 37

what are the top 2 ways to pump air (from bar graph)

Answer 37

1. Drug 50% | 2. Blood sample 30%

Question 38

name 5 results of blood-bubble interactions

Answer 38

1. denaturation of plasma proteins 2. adsorption of phospholipids/fibrinogen 3. complement activation 4. microthrombi production 5. endothelial wall damage

Question 39

name 4 safety devices to prevent emboli

Answer 39

1. low level alarm 2. air bubble detector 3. ALF/Cardiotomy filter 4. one-way valve in arterial line & vent line 5. use of prebypass checklist

Question 40

name 5 ways you can minimize biologic emboli *know*

Answer 40

1. use transfusion filters 2. adequately anticoagulate 3. minimize surface area of circuit 4. use membrane oxygenator 5. minimize complement, platelet and neutrophil activation

Question 41

name 3 ways you can minimize induction of foreign paticles *know*

Answer 41

1. circulate crystalloid solution through entire circuit 2. dont use silicone tubing in arterial pump head 3. use medical grade tubing

Question 42

name 5 ways you can minimize formation of gaseous microemboli *know*

Answer 42

1. check all equipment for proper operation 2. ensure tubing connections are secure 3. proper use of all safety devices 4. avoid air in venous line 5. flush circuit with CO2 prior to priming