2020 Review Flashcards
If there is a decrease in SvO2, what should you do?
increase flows
Why does blood pressure decrease when the clamp comes off?
lung ventilation
When is the best time for plasmapheresis?
After anesthesia and before they cut into patient
What is plasmapheresis?
a device separates whole blood into the cellular compartments and plasma. The plasma is then discarded and replaced with colloid fluid, combined back with the cellular components and returned to the same patient
what is the ideal post dilution hematocrit on bypass
23-35
with no heparinization, what should be the lowest flow rate?
1 LPM.
what is perfusion pressure
pressure of oxygen to tissues
what is the ideal place for O2 analyzer?
after the gas line
what can lead to an increase in glucose and hyperkalemia on pump
decrease in insulin
when is serum glucose the highest?
during rewarming
hyperkalemia definition
a potassium level in your blood that’s higher than normal
what should you do if you have a runaway pump?
clamp arterial line
if there is gas flow interference when you are on pump and there is no O2 tank available, what should you do?
put the O2 line in the roller head
what is the best indicator of adequacy of perfusion
SvO2
what is hemoglobinuria and what does it show a perfusionist?
excretion of free hemoglobin in the urine and is a CPB trauma
when scrubbing into surgery, how long should you scrub your hands for?
2-5 minutes
a contraindication for cell salvage is
use of micro fibrillar collagen hemostat
antibiotics aspirated in cell salvage cause what?
hemolysis
what is the ratio of cell salvage
7 parts citrate to 1 part blood
if you given back a significant amount of cell saver and the PTT and PT are still not correct, what should be given?
FFP
PRBCs with citrate can be stored for how long?
35 days
for an air embolism, what should be done immediately
put the patient in trendelenburg position
what is normal NIRS range?
75-80
what does NIRS measure?
cerebral oximetry
local SaO2 and SvO2
what does NIRS consist of?
four diodes per pad
what does BIS monitoring tell us?
indication of depth of anesthesia
90-100 BIS tells us
patient is awake
60-90 BIS tells us
light to moderate mediation
40-60 BIS tells us
goal sedation during surgery
20-40 BIS tells us
brain suppression
0 BIS tells us
electrical silence meaning absence of brain activity
what is the use for TEE during cardiac surgery?
to check for air
what does EEG stand for?
electroencephalogram
what does an EEG tell us?
a test used to find problems related to electrical activity of the brain. usually used to check for adequate brain perfusion
what is the risk of giving a lot of bank blood?
- citrate toxicity
- hypotension
- decreased pulse pressure
- increased LVEDP and CVP
- arrhythmias
what does temporary epicardial pacing consist of?
pacing wires sutured to the epicardium of the heart, on the atrium, and on the ventricle
without myocardial protection, irreversible damage begins to occur after how long?
20 minutes
in a patient with DMII, upon initiation of CPB, what happens?
causes a dilution effect that stimulates alpha cells in the islets of Langerhans which will cause glucagon release and will cause glucose in the blood to rise
reperfusion injuries occur when?
when the cross clamp is removed
what causes reperfusion injuries?
air
what is reperfusion injury?
myocardial, vascular, or electrophysiological dysfunction after blood supply returns to once ischemic tissue
what are symptoms of reperfusion injury?
inflammation (neutrophil accumulation), oxidative damage, arrhythmias, and endothelial cell damage
five mediators of reperfusion injury
- Ca influx
- neutrophils
- compliment activation
- O2 free radicals
- edema
what do neutrophils do in reperfusion injury?
they release oxygen free radical scavengers
what else does neutrophils also produce that might help reperfusion injury?
superoxide
superoxide dismutase is an enzyme that helps break down potentially harmful oxygen molecules in cells, which might prevent damage to tissues
how are neutrophils affected by reperfusion?
they are chemotactically altered by reperfusion from the release of protease
this can cause endothelial stiffness, which decreases the flexibility needed for capillary flow, promotes microembolization and is implicated in post-ischemic edema
during reperfusion injury, what do oxygen free radicals produce?
peroxide, which causes damage to the cells
how do oxygen free radical scavengers work?
they work in the body by converting hydrogen peroxide to water and CO2
respiratory acidosis values
pH is <7.35
CO2 is > 45
HCO3- is normal
BE is negative
respiratory alkalosis values
pH is >7.45
pCO2 is <35
HCO3- is normal
BE is positive
compensated respiratory acidosis has what values
normal ph
high pCO2
high HCO3-
compensated respiratory alkalosis has what values
normal pH
low PCO2
low HCO3-
what do you do to correct metabolic acidosis
give bicarb
what will be seen with uncompensated respiratory acidosis
low pH
high CO2
normal bicarb
what can metabolic alkalosis be treated with
lactated ringers
ammonium chloride
diamox
what is the main drop in blood pressure after initiation of bypass?
hemodiluution of catecholamines causes hypotension upon initiation
what is the partial pressure of O2 at 760 torr?
160
increasing the peep will ___ O2
increasing the peep will decrease O2
at a given pO2, increasing the pCO2 results in what?
less oxygen bound to hemoglobin
what could be the cause if the heart start beating during a redo CABG after cross clamp is on
the hear has been rewarmed from patent mammary
increased pressure in the hemoconcentrator can be due to
decrease in temperature
to increase the partial pressure of O2 in the oxygenator, what can be done on pump?
increase FiO2
what are heparin coated oxygenators?
polymethylpentene and polypropylene
what are the advantages of polymethylpente oxygenators? (PMP)
- low transmembrane pressure drop
- can be heparin coated
- will not “wet out”
what is membrane shunting?
when blood passes through the oxygenator without being oxygenated
what is the most common complication of KVAD?
reversal of flow and entrapment of air
max vacuum setting for VAVD
-90 mmHg
the average negative gravity pressure in the venous line from patient to reservoir is
-15 to -30 mmHg
what is the cause of most hemolysis from suckers
blood to gas interface
the longer the tubing is the ___ the pressure drop
the longer the tubing is, the greater the pressure drop
pressure drop is in direct proportion to what
tubing length
PVC tubing in roller heads will start deteriorating in what direction
by cracking and breaking from outer edge in
what are the differences between the different types of flow probes?
electromagnetic: direct blood contact, electro chemical contact with sensors
ultrasonic: no contact with blood, uses waves to calculate flow
doppler: acoustics to measure blood flow
what are positive displacement pumps also known as
occlusive roller head
characteristics of positive displacement pumps
- preload dependent
- afterload independent
- high negative inlet pressure
- high positive outlet pressures
- occlusive
characteristics of an under occluded roller pump
- inaccurate flow measurements
- backflow
- excessive turbulence
if the inflow to a roller pump is occluded, what will happen
cavitation with occur
centrifugal pumps are ____ dependent and use ____ to move fluid
after load dependent and use kinetic energy to move fluid
what is the most common mechanical complication associated with centrifugal heads
magnetic decoupling
micro emboli from the reservoir is from
vortexing
the heat transfer in heat exchanger occurs due to
forced convection and conduction
what is the prebypass filter made of
polyurethane
what is the size of the prebypass filter
.2-5 microns
the best material for a filter is
polyester
screen filters are by ___ size
pore size
size of a gas filter
.2 microns
size of a leukocyte depleting filter
.2 microns
size of a cardiotomy filter
20-40 microns
size of a pall filter
40 microns
