7. Embolic Events- Exam 2 Flashcards
What is the incidence of clinically obvious strokes post CPB
1-5%
MRI suggests that there could be new infarcts in what % of those same patients
30%
is the source of strokes necessarily from CPB
nope
-patients are a major contributor
what % of CABG patients experienced cerebral infarct prior to surgery
50%
what are the 3 types of infection
- Biologic (bloodborne)
- Foreign Material (Circuit/Manufacturing)
- Gaseous
Micro vessels are the main target for emboli. What are their diameter
3-500 micrometers in diameter
what is the greatest period of risk for emboli
- Insertion of arterial cannula
- Initiation of bypass (hypotension)
- Cross-clamp application/removal
- Use of centrifugal pump (any time you have a decrease in flow)
trauma to the aorta can contribute to brain infarctions for how long
up to 1 month
what organ is at the greatest risk for emboli
brain
Formation of biologic emboli: homologous transfused blood- risk increases with what
storage time
Formation of biologic emboli: inadequate anticoagulation with contact with what
foreign surface
Formation of biologic emboli: areas at risk from inadequate anticoagulation-contact with foreign surface
minimal flow stagnant areas turbulence cavitation rough areas
Formation of biologic emboli: areas of the circuit at risk from inadequate anticoagulation-contact with foreign surface
connectors bubble oxygenators ALF cardiotomy rservoirs intraluminal projections
Formation of biologic emboli: Trauma to ____ cells of epicardium and trauma to ____ of the surgical wound
fat
tissue
Formation of biologic emboli: do you need CPB to produce fat emboli? what other sources are there?
No
Median sternotomy
Thoracotomy
Formation of biologic emboli: how much fat within a circuit comes from cardiotomy suction
2/3
Formation of biologic emboli: fat emboli can be large particles of how many microns
4 - 200 microns
Formation of biologic emboli: what organs can fat emboli be found in post bypass
kidney lungs heart brain liver spleen
Formation of biologic emboli: complement activation sue to what
surface contact- activation process
Formation of biologic emboli: complement activation from surface contact includes what
platelets and neutrophils
platelet counts drop what % with initiation of bypass
30-50%
-also drop in # of functional platelets
describe platelets role with decreased #
post-op bleeding
neurologic dysfunction
release of histamine (membrane permeability)
release of serotonin/thromboxane (vasoconstriction)
name some examples of foreign particle emboli
cotton fibers plastic particles filter material spallation bone wax
name 4 sources of gaseous microemboli
bubble oxygenators
temp gradients
surgical air
pump/circuit problems
bubble oxygenators can produce what size emboli thats associated with CPB mortality and morbidity
35 - 40 micrometers
- mainly oxygen
- solution was to transition to membrane oxygenators
name 3 ways to create surgical air
- heart contracts before chambers are completely de-aired
- surgeon cuts into chamber of beating heart
- placement of arterial, venous or LV vent cannulae
how long is surgical air present in the heart post CPB
30 to 40 min
what is a solution to correct surgical air
flush with CO2… 86% of buubles gone within 1 minute
name 5 ways to pump air
- inattention to level in VR
- reversed roller pump
- retrograde flow through centrifugal pumo
- drug injections into circuit
- inadequate debubbling of ALF
- –more on slide 15
what % of air is pumped due to inattention to VR level
37%
what % of air is pumped due to aortic root air during plegia administration
29%
what % of air is pumped due to unexpected heart beat
10%
what % of air is pumped due to reversed LV vent line
9%
what % of air is pumped due to pressurized cardiotomy
5%
what % of air is pumped due to ruptures arterial pumphead tubing
5%
what % of air is pumped due to unnoticed rotation of arterial pump head
5%
what are the top 2 ways to pump air (from bar graph)
- Drug 50%
2. Blood sample 30%
name 5 results of blood-bubble interactions
- denaturation of plasma proteins
- adsorption of phospholipids/fibrinogen
- complement activation
- microthrombi production
- endothelial wall damage
name 4 safety devices to prevent emboli
- low level alarm
- air bubble detector
- ALF/Cardiotomy filter
- one-way valve in arterial line & vent line
- use of prebypass checklist
name 5 ways you can minimize biologic emboli know
- use transfusion filters
- adequately anticoagulate
- minimize surface area of circuit
- use membrane oxygenator
- minimize complement, platelet and neutrophil activation
name 3 ways you can minimize induction of foreign paticles know
- circulate crystalloid solution through entire circuit
- dont use silicone tubing in arterial pump head
- use medical grade tubing
name 5 ways you can minimize formation of gaseous microemboli know
- check all equipment for proper operation
- ensure tubing connections are secure
- proper use of all safety devices
- avoid air in venous line
- flush circuit with CO2 prior to priming
