Embolic Events- Exam 2 Flashcards Preview

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Flashcards in Embolic Events- Exam 2 Deck (46)
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1

What is the incidence of clinically obvious strokes post CPB?

~1-5%

2

MRI suggests could be new cerebral infarcts in what percent of same patients?

~30%

3

What is the source of strokes not necessarily?

CPB

4

What is a major contributor to strokes?

Patient

5

What percent of CABG patients experience cerebral infarct prior to surgery?

~50%

6

Subclinical

hard to detect

7

Types of emboli

Biologic (bloodborne)
Foreign material (circuit, manufacturing)
Gaseous

8

What are the main targets of emboli? What size?

Micro vessels; 3 to 500 um in diameter

9

What is the period of greatest risk?

Insertion of arterial cannula
Initiation of bypass
XC application/ removal
Use of centrifugal pump

10

Why is initiation of bypass one of the riskiest periods for emboli?

Hypotension; most circuit "junk"

11

Why is XC application/removal one of the riskiest periods for emboli?

Manipulation of the aorta; trauma to aorta can contribute to brain infarctions for up to 1 month

12

When does the use of a centrifugal pump become a risk for developing emboli?

Any time you have a decrease in blood flow

13

Biologic Emboli

Fibrin/fibrinogen microthrombi
Fat or lipids
protein
cold-reacting antibodies
calcium fragments
bone fragments
muscle fragments
platelet aggregates
neutrophil aggregates
RBC aggregates
inadequate anticoagulation
contact with foreign surface

14

Formation of biologic emboli in homologous transfused blood increases with what?

Storage time

15

What areas are at risk with the formation of biologic emboli?

Minimal flow
Stagnant areas
Turbulence
Cavitation
Rough surfaces

16

What areas of the circuit can form biologic emboli? (higher risk areas)

Connectors
Bubble oxygenators
Arterial line filters
cardiotomy (venous) reservoir
intraluminal projections

17

What kind of trauma can cause biologic emboli?

Trauma to fat cells of epicardium and trauma to tissue to the surgical wound

18

What, besides bypass, can produce fat emboli?

Median sternotomy
thoractotomy

19

What fraction of fat/lipid emboli within a circuit come from cardiotomy suction? What size particles?

2/3; 4-200 micron particles

20

Biologic Emboli found in what organs post bypass?

Kidney, lungs, heart, brain, liver, spleen

21

Platelet count drops what percent with initiation of bypass?

30-50%

22

What drops with initiation of bypass

Platelet count and # of functional platelets

23

Platelets related to...

Post op bleeding, neurologic dysfunction, release of histamine (membrane permeability), release of serotonin/thromboxane (vasoconstriction)

24

Neutrophils related to...

Aggregation, interaction with endothelial cells, change in permeability

25

Foreign Particle Emboli

Cotton fibers
Plastic particles
Filter material
Tubing fragments (spallation)
Metal
Talc
Thread
Bone wax
Microfibrillar collagen
Silicone antifoam

26

Bubbles of what size are associated with CPB mortality and morbidity?

35-40 um size

27

What are in the bubbles that cause gaseous microemboli?

Mainly oxygen

28

What causes formation of gaseous microemboli?

Bubble oxygenator
Temperature gradients
Surgical air
Pump/Circuit problems

29

What causes surgical air

Heart contracts before chambers completely de-aired
Surgeon cuts into chamber of beat heart
Placement of arterial, venous, or LV vent cannula

30

What is present in heart how long post-bypass?

30-40 minutes