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22 Cards in this Set
- Front
- Back
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According to the Article, the Lower Limit of Autoregulation (LLA) for non anesthetized patients should be:
a) 10% less than the resting MAP b) 15% less than the resting MAP c) 25% less than the resting MAP d)25% greater than the resting MAP |
c) 25% less than the resting MAP
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True/False
Normal physiological changes occurring with the sitting position are mainly attributed to gravity and area exaggerated during general anesthesia. |
True
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True/False
The upright sitting position decreases venous return by all the gravitational pooling of blood in the lower extremities. |
True
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True/False
CPP decreases by approximately 15% simply by reaching the sitting position in a nonanesthetized patient and could further decrease under anesthesia d/t vasodilation and impairment of venous return |
True
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To achieve the minimal CPP for which autoregulation is thought to be effective, MAP must be maintained higher than ______mm Hg.
a) 50 b) 55 c) 60 d) 65 |
d) 65
CPP = MAP-ICP 65-15=50mm Hg (low end on autoregulation curve as we know it) |
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True/False
In the article Drummond argued that the actual range for humans is even higher and that the lower limit of autoregulation should be estimated individually based on the patient's resting MAP. |
True
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The LLA (lower limit of autoregulation) for non anesthetized patients is thought to be at a MAP of
a)25% less than resting value b) 20% less than resting value c)10% less than resting value d) none of the above |
a)25% less than resting value
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Patients with chronic HTN their autoregulation curve is shifted to the ______ which requires _______CPP/MAP to ensure adequate cerebral perfusion.
a)right, higher b)left, higher c)right, lower d)left, lower |
a) right, higher
The CBF autoregulation shifted to the right and then you need a higher MAP to maintain adequate cerebral perfusion. |
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True/False
Assume a 0.77 mm Hg decrease for every cm gradient or 1 mm Hg for each 1.25 cm between carotid artery and the site of the BP cuff in the seated position |
True
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Inlet-outlet pressure is defined as __________whereas inside minus outside pressure is defined as_________.
a) perfusion pressure; transmural pressure b) transmural pressure; perfusion pressure c) pressure gradient; perfusion pressure d) pressure gradient; transmural pressure |
a) perfusion pressure
transmural pressure Perfusion pressure=inlet-outlet pressure Transmural pressure=inside - outside pressure |
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True/False
It has been suggested that a RANGE of normal LLA(lower limit autoregulation) vary from 70-93 mm Hg (instead of the standard 1953 publication of the LLA of 50 mm Hg) with a mean value of 80 +-8 mm Hg. |
True
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Should the shoulders of the autoregulation curve be more rounded rather than the sharp inflection points showing a specific value?
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According to the article...yes.
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Cerebral autoregulation
a) maintains constant cerebral blood flow (CBF) between a mean arterial pressure (MAP) of 50-150 mm Hg b) Maintains a constant CBF at all MAP levels in the brain c) Depends in large part on cerebral vascular constriction and dilation d) Does not occur in HTN patients. |
a) maintains constant cerebral blood flow (CBF) between a mean arterial pressure (MAP) of 50-150 mm Hg
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Which of the following changes occurs in the sitting position during anesthesia:
a) Increase in MAP b) Decrease in pulmonary vascular resistance c) Increase in CVP d) Decrease of intrathoracic blood volume |
d) decrease of intrathoracic blood volume
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Cerebral perfusion pressure (CPP):
a) equals mean arterial pressure (MAP) b) Equals MAP divided by pulmonary vascular resistance c) Equals MAP minus CVP or ICP (whichever is higher). d) Is the same as the perfusion pressure in the arm in an upright patient |
c) Equals MAP minus CVP or ICP (whichever is higher).
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The normal lower limit of cerebral autoregulation (LLA) is:
a) 45 mm Hg b) 70-93 mm Hg c) 94-110 mm Hg d) 111-120 mm Hg |
b) 70-93 mm Hg
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MAP at the arm in the supine position during deliberate hypotension:
a) Is applicable to all other areas of the body b) Is approximately 20 mm Hg higher than MAP in the cerebral circulation c) Cannot be readily controlled d) Cannot be utilized to estimate MAP at the Circle of Willis |
a) Is applicable to all other areas of the body
When the patient is in the supine or in a lateral position, BP in the arm, heart, and brain are essentially the same. |
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In the upright beach chair position, the external auditory meatus is an external landmark that:
a) can be used to estimate the position of the base of the brain b) can be used to estimate the most cephalad position of the cerebral cortex c) Can be used to estimate MAP in the brain only when an intra-arterial catheter is used to measure blood pressure d) Does not change its vertical height above the BP cuff as the patient's angle above the horizontal plane increases or decreases. |
a) can be used to estimate the position of the base of the brain
A pressure transducer placed at the level of the external auditory meatus (generally accepted as indicating the base of the brain) in an upright patient will read less than one placed at the heart or arm. |
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Blood pressure at the base of the brain decreases by:
a) 3.0 mm Hg for every cm of vertical height above the site of cuff measurement b) 2.5 mm Hg for every cm of vertical height above the site of cuff measurement c) 2.0 mm Hg for every cm of vertical height above the site of cuff measurement d) 0.75 mm Hg for every cm of vertical height above the site of cuff measurement |
d) 0.75 mm Hg for every cm of vertical height above the site of cuff measurement
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MAP at the arm blood pressure cuff in an upright, beach chair positioned patient:
a) has no specific relationship to MAP in the brain b) underestimates CPP in the brain c)Is approximately the same as MAP and CPP at the Circle of Willis d) Overestimates MAP in the brain |
d) Overestimates MAP in the brain
As has repeatedly been noted in this monograpy, BP cuff values at the brachial artery overestimate the actual mean intracranial blood pressure when the patient is upright. |
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Deliberately induced hypotension to a MAP of 50-60 mm Hg in the sitting position
a) carries the same risk as in the supine position b) eliminates any margin for error in case the pressure falls even further c) is a low-risk procedure d) Is the same for hypertensive and normotensive patients |
b)eliminates any margin for error in case the pressure falls even further
Although studies have shown that normal cerebral oxygen metabolism can be maintained down to a CPP of 30-40 mm Hg with deliberate hypotension (so MAP's are 45-55), values this low are not recommended. Such limits serve no useful purpose and leave no margin for error in case the lower CPP is further reduced. |
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At which angle of elevation above the horizotal plane is the vertical distance from the Circle of Willis to an upper arm blood pressure cuff the greatest:
a) 30 degrees b) 45 degrees c) 60 degrees d) 90 degrees |
d) 90 degrees
In the beach chair position a significant distance is present from the Circle of Willis to the most cephalad portion of the brain adn this distance increases as the angle above the horizontal plane increases. |
