Blue Book Flashcards
what is the venous reservoir bag made of
polyvinlychloride, a polymer, and a holder for support
what is commonly thought as the major advantage of the venous reservoir bag?
safety
the bag empties and collapses when the venous return stops. the collapsed bag is supposed to prevent air from being pumped out of the bag
what is the flaw in the thought that a venous reservoir bag is safer?
the collapsed bag does not prevent air from being pulled out of solution due to the occluded outlet line,
what are disadvantages of using the venous reservoir bag?
difficulty of air evacuation
volume management and increased venous return resistance
vacuum suction cannot be applied to the bag
air in the bag can be difficult to manage
what does having an external craniotomy help with in a bag circuit?
holding place for volume
venous bags can only hold about 3000ml. when the bag is full of volume, that causes increased resistance which can lead to a decrease in venous drainage.
if you hold volume in the reservoir, you decrease the venous resistance and allow the heart to empty out more
what is usually the size of a cradiotomy filter?
40 um
what does the defoamer inside the cardiotomy reservoir do?
alters the surface tension of bubbles and causes them to dissipate
what are the three types of membrane oxygenators?
filled flat plate membrane
flat plate membrane
hollow fiber membrane
what is the rolled flat plate membrane made of?
silicone
what is the flat plate membrane and the hollow fiber membrane made of?
polypropylene
what is gas transfer across an oxygenator membrane due to?
permeability of the membrane to the gas and the driving pressure of that gas
how does gas transfer move
from high to low pressure
the driving pressure of a gas is ____ _____ of other gases that may be present
totally independent
the rate of exchange is determined by what
by the pressure differential of the gas on either side of the membrane and permeability of the membrane to the fas
the greater the pressure differential is,
the greater the rate of exchange becomes
the greater the permeability of the gas is,
the greater the rate of exchange becomes
transfer rate =
driving pressure x permeability
what does oxygen capacity measure
the max amount of oxygen that the blood is capable of carrying
what is the formula for oxygen capacity (O2 capacity)
*assuming that the hemoglobin is 100% saturated
1.34 x Hgb + .003 pO2
expressed as volumes % (m O2/ 100 mL blood)
what is the ml of O2 that is carried by one gram of hemoglobin
1.34
If the saturation is not 100%, then the amount of oxygen carried is different. What is this value known as
oxygen content
what is the formula for the O2 content
1.34 x Hgb x % saturation (in decimal) + .003 x pO2
what is the formula for oxygen saturation (%)
oxygen content / oxygen capacity
what is an oxygenators oxygen transfer rate?
due to the manufacturer’s design and membrane permeability to oxygen, the oxygen transfer rate is the amount of oxygen a membrane will transfer on each pass regardless of the venous saturation
