CBP Flashcards
what is a perfusionist?
a certified medical technician responsible for extracorporeal oxygenation and flow of the blood during open-heart surgery and for the operation and maintenance of equipment (such as a heart-lung machine) controlling it.
Perfusionists responsibilities
Setting up, operating and maintaining complex perfusion equipment
Monitoring circulation
Regulating the levels of oxygen and carbon dioxide in the blood
Regulating the body temperature
Measuring laboratory values such as arterial/venous blood gases
Administering medication and blood products via the bypass circuit under the supervision and direction of the anesthesiologist and surgeon
What are components of the circuit
♥ Oxygenator / Heat Exchange Unit
♥ Pump Head
♥ Venous Reservoir
♥ A-V Loop
♥ Arterial Filter
♥ Filtered Cardiotomy
♥ Cardioplegia Delivery System (MPS)
♥ Autologous Blood Conservation Technologies (Cell Saver)
What is the pump primed with?
♥ Normosol solution
♥ 10,000 units Heparin
♥ 200 cc 25% Mannitol
♥ 50 mEq’s Bicarb
♥ 200 mg Lidocaine
♥ 80 mEq’s K+
♥ 5 grams Magnesium
What is the AV-Loop?
the connection of the patient’s venous system to the patient’s arterial system with an extracorporeal circuit
What and where does the venous cannula drain
RA into the venous reservoir
Where is the arterial cannula inserted?
Where does it return blood to?
Inserted into the ascending aorta.
Delivers oxygenated blood to the body
Where does the basket in the mid cannula (venous) sit, and what part of the the body does it drain?
right atrium, drains upper body
where the basket that drains the lower body sit?
inferior vena cava
What does the venous reservoir act as?
Acts as the atrium of the heart-lung machine circuit
How is venous drainage achieved?
gravity and vacuum
why would vacuum of venous drainage be added?
to gain more patient volume & empty the heart if needed
What does the venous o2 saturation monitor measure?
constant measurement of venous o2 saturation & hct
What does the bubble detector do?
Safety mechanism that protects pts from receiving air embolus
where can the bubble detector be placed?
any portion of pump tubing
What is the E clamp?
a safety device that is attached to the arterial line.
What is the E clamps function?
to stop arterial flow to the patient when either air or low blood volume is detected
what can occur if air enters the venous line?
an airlock
What does a roller pump do?
compresses the blood tubing, which creates an occulsion point as it mechanically propels blood forward
What are the issues with the roller pump?
it’s traumatic to blood cells
the roller pump remains constant despite a patient’s ______
Why is this a problem/what can it lead to?
afterload
If the arterial inflow line is clamped the pimp continues to push blood forward which can rupture the arterial inflow tubing
If the venous reservoir runs dry, what is more likely to happen with a roller pump?
More likely to entrain air, which can lead to air embolism.
What does the pump do?
propels the blood through the patient’s circulation (replaces the heart)
how does the roller pump work?
positive displacement
How does the centrifugal pump work?
Non-occlusive constrained vortex– uses gravity and spins blood through a cone
what are benefits of the centrifugal pump?
less traumatic to blood cells
can’t produce excessive negative pressure= reduces risk of air embolus
the centrifugal pump flow decreases when it is confronted by excessive _____
afterload
What’s the disadvantage of the centrifugal pump?
It’s lack of occlusion point.
If there is an excessively high afterload, blood backs up towards the venous circulation, which reduces the pts circulating blood volume
What happens in the oxygenator?
gas exchange occurs (it replaces the lungs)
Primary function is the oxygenation & removal of CO2 from blood. This is the “ Lung”
Whats the secondary function of the oxygenator?
Secondary function is blood temperature management.
Lowering 1 degree celsius reduces_____
metabolic rate by 7%
What are the 3 types of hypothermia?
mild, moderate, profound
What does the O2 blender do?
controls the FIO2 and the delivery speed of the oxygen-air mixture to the oxygenator
What gases does the perfusionist use?
desflurane and isoflurane
Why are those gases used?
♥ Provides continuous and
easily titrateable level of
anesthesia
♥ Lowers chance of recall
♥ Allows heart to survive a
longer period of time before
injury due to ischemia.
“Anesthesia Preconditioning”
♥ Quick On-Off properties due
to its low blood gas
solubility makes it very
manageable to control BP
What is the last safety device before blood enters pt?
Arterial filter
what does the arterial filter do?
Removes air micro- and macro-bubbles via purge line
What does the arterial line manometer measure?
circuit line pressure
♥ Provides safety mechanism
for the heart lung machine
by verifying proper
placement of aortic cannula
and assuring that over
pressurization of the circuit
does not occur
What does the arterial line manometer measure?
circuit line pressure
♥ Provides safety mechanism
for the heart lung machine
by verifying proper
placement of aortic cannula
and assuring that over
pressurization of the circuit
does not occur
What is the function of the cardiotomy?
♥ Receives blood from
surgical field via pump
suctions
♥ Acts as backup
reservoir when
excessive volume is
reached
♥ Receives volume when
vents are put into the
heart
What is the function of the cardiotomy?
♥ Receives blood from
surgical field via pump
suctions
♥ Acts as backup
reservoir when
excessive volume is
reached
♥ Receives volume when
vents are put into the
heart
What does the Aortic Root vent do?
prevents LV distention when the blood does get through the pulm circulation w 2 stage cannulation
When is the left ventricular pulmonary vent used?
valve replacement cases
what does the left ventricular pulmonary vent do?
♥ Mimics the same duties
of the aortic root vent in
limiting LV distention.
“Starlings Curve”
How is cardiac arrest achieved?
High K+ infusion
(has significant vasodilatory effect)
via what routes is cardioplegia administered?
-aortic root (antegrade)
-coronary sinus (retrograde)
-vein grafts
-coronary ostia
What effects does the high K+ infusion have?
vasodilatory effects
what is magnesium used for?
membrane stability
what lab values does the blood analyzer produce?
PH, PCo2, PO2, Na+, K+,
Ca++, Glu, Lac, Hct, HCO3,
BE, SO2
What ACT must be maintained and how often is it measured?
> 480 every 30 mins
What ACT must be maintained and how often is it measured?
> 480 every 30 mins
what are RBCs washed in for cell saver?
NS–> concentrated at hct 50 (75%)
what does large amounts of cell saver blood indicate?
large plasma loss
what is the major disadvantage of cell saver?
elements of the patient’s blood are “washed” off especially clotting factors.
End result potential bleeding problems with massive blood loss
what is the major disadvantage of cell saver?
elements of the patient’s blood are “washed” off especially clotting factors.
End result potential bleeding problems with massive blood loss
what does AGF stand for?
Autologous Growth Factor
What does platelet rich contain?
> 1,000,000 plts/ul
7 growth factors
what does platelet rich do?
stimulate and accelerate bone and soft tissue healing
what is added to the platelet rich?
Calcium & Thrombin added to produce gel formation
what does plt poor contain?
mostly plasma w few plts
what is plt poor recommended for ?
use in plt aggregation
when is plt poor used?
Applied on top of “RICH” to hold it in place like a bandage
minimum hct cold
21%
minimum hct warm
24%
minimum hct warm
24%
what MAP should be maintained?
60-90 mmHg
how much urine output should be maintained?
1-2cc/kg/hr
what temp do you want to maintain?
Drift to 32 degrees celsius
how often should you do abgs?
30 mins
how often do you document flows and UOP?
Q15
how often is cardioplegia administered?Q
Q15-20 mins
how often is cardioplegia administered?Q
Q15-20 mins
how often should you do heparin/protamine assays?
Q30 mins
when do you use cell saver?
all cases
What is contact activation?
(Inflammation) - a series of host-defense mechanisms designed to attack foreign substances or tissue injury.
results from blood coming in contact with plastic tubing, filters, connectors, stainless steel heat exchangers, and blood to gas interfaces
Produces an overwhelming and systemic activation of the inflammatory cascade. (Systemic Inflammatory Response Syndrome: SIRS)
how does the complement system affect the lungs?
Activated WBC’s are deposited or sequestered in the lungs; where they release superoxides and lysosomal enzymes, which produce endothelial damage & in turn results in the accumulation of extravascular water. “PUMP LUNG”
what is the heparin -protamine complex associated with?
activation of the classic pathway and production of C3a,C4a and C5a.
how should protamine be administered?
SLOWLY
how should protamine be administered?
SLOWLY
what does the air to interface inflammatory response do?
♥ Formation of gaseous microemboli.
♥ These gaseous microemboli disrupt
microcirculation by producing tissue & organ ischemia.
what does the air to interface inflammatory response do?
♥ Formation of gaseous microemboli.
♥ These gaseous microemboli disrupt
microcirculation by producing tissue & organ ischemia.
mechanisms to reduce blood activation
♥ Closed venous reservoirs
♥ Bio-compatible surfaces
♥ Judicious use of suction, cell savers, vents
♥ Dosing the proper amount of heparin & protamine
♥“Microcircuitry” (Smaller Compact Circuits)
benefits of closed venous reservoirs
♥ Eliminates the majority of air/blood interface.
♥ Better flow dynamics, reduced areas of stasis.
♥ No defoaming agents, no nylon filter sock..
♥ Reduced complement activation.
♥ Preserves platelet function
♥ Reduced post-op bleeding.
♥ Improved post-op lung function.
why are pts on CPB rendered hypothermic?
reduce metabolic rate
why are pts on CPB rendered hypothermic?
reduce metabolic rate
priming with anything other than blood produces:
Hemodilution:
-decreased hematocrit
-decreased o2-carrying capacity
-decreased blood viscosity (good if hypothermia is used)
-decreased plasma concentration of drugs and plasma proteins
-increased microvascular flow (d/t reduced viscosity)
-
priming the CPB machine with a balanced salt solution reduces all of the following EXCEPT:
-microvascular flow
-plasma drug concentration
-oxygen-carrying capacity
-blood viscosity
microvascular flow
When is awareness MOST likely to occur during CABG surgery on pump?
-induction of anesthesia
-aortic cannulation
-rewarming
-sternotomy
sternotomy (d/t intense surgical stimulation
next most common: rewarming
what can be used if the pt has a heparin allergy?
bivalirudin, hirudin, or another factor 10 inhibitor
whats the ideal range of SBP during aortic cannulation?
90-100 mmhg or MAP <70mmHg
what is used to reduce bleeding risks?
antifibrinolytics: aminocaproic acid or TXA or cell saver
does cardioplegia arrest heart is systole or diastole?
diastole
K+ increases resting membrane potential which locks the voltage-gated Na+ channels in the closed-inactive state
does cardioplegia arrest heart is systole or diastole?
diastole
K+ increases resting membrane potential which locks the voltage-gated Na+ channels in the closed-inactive state
how is the heart restarted?
infusint the coronary circulation with warm, normokalemic blood
where is antegrade cardioplegia administered?
aortic root where it enters the coronary arteries
where retrograde is cardioplegia administered
through cannula placed in the coronary sinus
