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Perfusion Circuits > Pumps and Heat Exchangers > Flashcards

Pumps and Heat Exchangers Flashcards

1
Q

In an ideal pump, the flow should be able to reach up to ____?

A

7 Liters/minute

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2
Q

what are other ideal characteristics to have on a pump?

A
  • minimal blood hemolysis
  • limited turbulence or stasis
  • disposable if direct contact with blood
  • exact and reproducible flow calibration
  • manual hand crank
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3
Q

Roller displacement pumps have a ___ raceway with ____ _____ tubing

A

curved raceway

length flexible tubing

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4
Q

Describe the set up of roller displacement pumps

A

two rollers mounted ends rotating arms, 180 degrees apart allowing contact of tubing at one location at all times

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5
Q

how does the roller displacement pumps move fluid

A

roller compresses tubing against racing pushing fluid ahead of moving roller

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6
Q

what three things determine fluid flow of roller displacement pumps

A
  1. occlusion of roller
  2. revolutions per minute (RPM)
  3. tubing size
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7
Q

how do you change occlusions?

A

by adjusting rollers compress tubing

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8
Q

what can over occlusion cause?

A

cause hemolysis and tubing wear

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9
Q

what can under occlusion cause?

A

it can compromise forward flow to patient

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10
Q

what are the three different methods to test roller pump occlusion?

A
  1. fluid drop method
  2. pressure drop method
  3. Dynamic occlusion method
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11
Q

how do you conduct the fluid drop method?

A
  • arterial line raised 30 inches above pump head
  • slightly loosen occlusion let fluid fall slowly
  • gently tighten occlusion until fluid just stops falling
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12
Q

what should the drop rate be for the roller pump occlusion?

A

drop rate 1 inch/min

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13
Q

when testing the roller pump occlusion, you should _____ and check in ___ locations

A

rotate rollers and check in 6 locations

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14
Q

fluid column for fluid drop method is how high above pump

A

30 cm

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15
Q

Describe the pressure drop method

A

build pressure in system and watch pressure in transducer 180-300 mmHg
turn the pump off and watch the pressure drop

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16
Q

what do you have to have in order to move the blood forward?

A

have to have occlusion in order to compress the tubing to move the blood forward

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17
Q

what is the roller displacement pump also known as?

A

positive displacement pump

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18
Q

how will wrong occlusion affect displacement

A

wrong occlusion will not displace amount of blood

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19
Q

what is runaway pump

A

motor staff comes disconnected from machine and just continues to spin faster and faster

  • no safety devices can stop it
  • must turn circuit breaker off
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20
Q

definition of cavitation of air

A

sucking air out of solution

-different from air from the atmosphere because caveated air will just go back into solution

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21
Q

name complications of roller pumps (7)

A 
improper occlusions
calibration errors
sapallation
loss of power
runaway pump 
over pressurization 
cavitation of air
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22
Q

what is the centrifugal rotary pumps used for

A

main arterial head

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23
Q

the ____ the resistance in the centrifugal rotary pumps, the _____ flow

A

higher the resistance, less flow

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24
Q

what kind of pump does a centrifugal rotary pump have?

A
  • non occlusive pump
  • smooth plastic cones or vane impeller contained in polycarbonate housing
  • magnet located in both disposable pump and in pump console
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25
____ causes fluid movement in centrifugal pump
rotation
26
centrifugal pumps are ____ and ____ dependent
pre load and after load dependent
27
what kind of flow probe does the biomedicus use?
electromagnetic | everything else uses ultrasonic
28
how does ultrasonic flow measurement work?
- no direct blood contact | - measures flow based on Doppler principle or ultrasound transit-time
29
How does electromagnetic flow measurement work?
- direct blood contact | - flow measured by electromagnetic flow principle
30
what is essential to have for the McKay rotoflow pump?
gel for pump | -pump usually built into the base of the machine
31
what are complications with the centrifugal pump?
power loss depriming of cone magnet decoupling inadvertent outflow obstruction, kink line or clamp results in no/low flow of patient retrograde flow = exsanguination of patient with no/low RPMs or line clamp
32
what does depriming of cone in centrifugal pump mean
air in cone, will not generate flow
33
what is retrograde flow
flow reverse back into the body
34
how were heat exchangers used in the early days?
only used to keep patient warm
35
in the early days, how did you lose heat from patient?
open chest respiration perfusion circuit with no integral heat exchanger
36
early model heat exchangers were ____ and made out of what three things?
were reusable | made out of glass, steel, and other materials
37
what were the development of disposable heat exchangers due to
pyrogenic reactions | difficulty in cleaning
38
how does heat transfer work on the heat exchanger?
energy is transferred into and out of HE by non sterile water that is circulated by a Heater Cooler unit attached to the oxygenator by tubing or "lines"
39
how is the water heated in the heat exchanger?
by heating unit in H/C
40
how is the water cooled?
ice is added to cool
41
water provides _____ of temperature with no _____
provides even distribution of temperature with no hot spots
42
what materials are used
stainless steel pvc tubing coil polyurethane polyethylene terephthalate (PET)
43
what is the surface area of the heat exchanger
large size folding of material increases surface area could tube (PVC in ice bucket)
44
what does having a larger surface area help?
better transfer
45
what is conduction method
takes place where when there is a difference in temperature (temp gradient) - is proportional to the difference in temperature ex: a spoon in cup of hot water
46
what is convection method
- mass movement of molecules from one place to another - great effect on patient in OR from a cold room with open chest ex: ovens
47
what are the two mechanisms of heat exchanger during CPB
- forced convection as water and blood flow past stainless steel interface - conduction within the stainless steel components - heat exchanged into or out of blood and thus into or out of patient
48
the rate or warming is limited during CPB due to
- microair formation - as any fluid is heated, any air dissolved in solution will become less soluble which will result in air coming out of solution when fluid temperature increases rapidly
49
blood damage is caused due to blood protein denaturation as temperatures reach
42"
50
increasing temperature may cause ______ while trying to warm ______
may cause neurological damage while trying to warm peripheral vascular beds
51
periphery warms ____ than major organs
slower than
52
the brain has been shown to be about ______ warmer than the _________ temperature
2" warmer than the nasopharyngeal temperature
53
what are the water sources for the heat exchanger
- wall water, but can be difficult to regulate temperature and pressure - units have one water bath for both heating and cooling
54
what are the separate compartments on dual heater cooler units
heating & cooling - some make own ice - some add ice to
55
Explain the Sarns Dual Cooler Heater operation
- cooling mode has 4 settings which will change water flow - water travels through ice tank - recirculation mode is a sing setting: water travels through heating manifold with the heating element off - heating mode has 4 temperature settings that are preset
56
what are the 4 preset temperature setting on the Sarns
30, 38, 40, 42 (+ or -2 degrees)
57
what is important to remember about LivaNova Sorin 3T
powered on its own circuit breaker (20 amp) for bother heater cooler and pump
58
Features of the Sorin 3T
- separate warm and cold cardioplegia tanks - compressor based cooling - independent safety system that prevents water temperature from reaching critical values - two chamber pumps minimize any pressure inside the heat exchanger - water evacuation feature enables emptying of the heat exchanger and tubing for a spill proof clean up
59
Features of Cardioquip MCH 1000
- 1600W heater delivers efficiency and performance - patented adaptive temperature control TM technology - insulated and valved cold water tank - temperature precision to 0.1 degree - customizable pump speeds - open water path
60
Precautions using Heater/Cooler systems
- do not turn on unit to recirculate unless the water lines are connected - H/C requires its OWN electrical outlet of 20 AMP

Perfusion Circuits (5 decks)

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