Flashcards in Embolic Events- Exam 2 Deck (46):
What is the incidence of clinically obvious strokes post CPB?
MRI suggests could be new cerebral infarcts in what percent of same patients?
What is the source of strokes not necessarily?
What is a major contributor to strokes?
What percent of CABG patients experience cerebral infarct prior to surgery?
hard to detect
Types of emboli
Foreign material (circuit, manufacturing)
What are the main targets of emboli? What size?
Micro vessels; 3 to 500 um in diameter
What is the period of greatest risk?
Insertion of arterial cannula
Initiation of bypass
XC application/ removal
Use of centrifugal pump
Why is initiation of bypass one of the riskiest periods for emboli?
Hypotension; most circuit "junk"
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
When does the use of a centrifugal pump become a risk for developing emboli?
Any time you have a decrease in blood flow
Fat or lipids
contact with foreign surface
Formation of biologic emboli in homologous transfused blood increases with what?
What areas are at risk with the formation of biologic emboli?
What areas of the circuit can form biologic emboli? (higher risk areas)
Arterial line filters
cardiotomy (venous) reservoir
What kind of trauma can cause biologic emboli?
Trauma to fat cells of epicardium and trauma to tissue to the surgical wound
What, besides bypass, can produce fat emboli?
What fraction of fat/lipid emboli within a circuit come from cardiotomy suction? What size particles?
2/3; 4-200 micron particles
Biologic Emboli found in what organs post bypass?
Kidney, lungs, heart, brain, liver, spleen
Platelet count drops what percent with initiation of bypass?
What drops with initiation of bypass
Platelet count and # of functional platelets
Platelets related to...
Post op bleeding, neurologic dysfunction, release of histamine (membrane permeability), release of serotonin/thromboxane (vasoconstriction)
Neutrophils related to...
Aggregation, interaction with endothelial cells, change in permeability
Foreign Particle Emboli
Tubing fragments (spallation)
Bubbles of what size are associated with CPB mortality and morbidity?
35-40 um size
What are in the bubbles that cause gaseous microemboli?
What causes formation of gaseous microemboli?
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
What is present in heart how long post-bypass?
Flush with Co2, what percent of bubbles are gone within 1 minute?
Why do you co2 flush?
Helps with air solubility, some of that CO2 transfers to the blood and PaCo2 will increase, increases vasodilation. Any type of embolism makes it easier to go to the brain
What, involving the venous reservoir, can lead to pumping air?
Inattention to level in venous reservoir
Vortexing of blood in venous reservoir at low volume levels
Pressurized cardiotomy reservoir
What involving the pump can lead to pumping air?
Reversed roller pump
retrograde flow through centrifugal pump
mechanical jarring of circuit components
over occluded arterial pump head
What involving the tubing can lead to pumping air?
Tubing reversed in roller head
leak/kink in tubing on negative side of the roller pump
disconnection/breakage, detachment of tubing
What involving the oxygenator can lead to pumping air?
disconnection/breakage detachment of oxygenator
pulsatile flow through microporous membrane oxygenator
What involving the arterial filter can lead to pumping air?
Inadequate debubbling, especially the arterial filter
What involving drugs can lead to air?
Drug injections into circuit and perfusion interventions
What involving volume can lead to air?
Inattention while transfusing volume to patient post bypass
What was the highest incidence of CPB emergency? Second highest?
Inattention to reservoir level (37%)
Aortic root air during CPS aminitration (29%)
What has the highest proportion of total emboli?
then blood samples
Adsorption/denaturation plasma proteins
Clumping red blood cells
Endothelial wall damage
Low level alarm
Air bubble detector
Arterial line filter (cardiotomy filter)
one-way purge line form arterial line filter to cardiotomy reservoir
one-way valve in vent line
one-way valve in arterial line
clear lines of ocmmunication
use of protocols, policies and procedures
Use of prebypass checklist
How do you minimize biologic emboli formation?
use of transfusion filters
design of circuit components
minimize surface area of circuit
use of membrane oxygenator
minimize complement/ immune activation
minimize platelet activation
minimize neutrophil activation
How do you minimize introduction of foreign particle emboli?
Componnet design and manufacturing
circulate crystalloid solution through entire circuit
flush circuit with cystalloid solution in conjuction with a pre-bypass filter in AV loops
don't use silicone tubing in arterial pump head
use medical grade tubing