76 Questions
What effect does the ACE inhibitor enalapril have on cerebral blood flow?
No significant effect on CBF
Why are the effects of anesthetics that vasodilate the cerebral circulation on ICP less dramatic when hypotension is slowly induced?
Reflect more effective compensatory mechanisms
Which drugs are mentioned as inducing hypotension and causing cerebral vasodilation?
Sodium nitroprusside and hydralazine
How do anesthetics that vasodilate the cerebral circulation affect cerebral blood volume (CBV)?
Increase CBV
What is a key factor determining the effects of vasoactive drugs on cerebral physiology?
The status of the autoregulation mechanism
How do catecholamine agonists and antagonists affect cerebral physiology?
Dependent on basal arterial blood pressure, autoregulation mechanism status, and BBB status
How do the effects of vasoactive drugs on cerebral physiology differ depending on autoregulation status?
They have both direct effects on cerebral vascular smooth muscle and indirect effects mediated by the autoregulatory response.
What happens to cerebral blood flow (CBF) when autoregulation is preserved and systemic arterial pressure is outside the limits of autoregulation?
CBF increases
What is the primary mechanism by which normal autoregulation maintains constant cerebral blood flow (CBF) despite rising mean arterial pressure (MAP)?
Cerebral vasoconstriction
In a situation where autoregulation is defective, how does cerebral blood flow (CBF) change in relation to arterial pressure?
CBF varies directly with arterial pressure
What determines the effects of vasoactive drugs on cerebral physiology according to the provided text?
Basal arterial blood pressure, autoregulation status, and drug-induced arterial blood pressure changes
How does preserved autoregulation impact cerebral blood flow when systemic arterial pressure rises within the normal autoregulatory range?
Cerebral blood flow remains constant due to maintained autoregulation
in which case CBF is maintained at lower MAP values due to hypotension ?
when hypotension is induced with a cerebral vasodilator
How does the administration of α1-agonists like norepinephrine and phenylephrine affect cerebral blood flow (CBF) in healthy patients?
Maintain or augment CBF
In patients with relative hypotension, what effect does the α1-agonist midodrine have on cerebral perfusion?
Increase perfusion pressure and flow velocity
What effect do β-mimetic drugs, such as norepinephrine with β1 activity, have on cerebral metabolism and cerebral blood flow?
mays Cause activation of cerebral metabolism and a coupled increase in CBF
What impact does the administration of norepinephrine have on cerebral blood flow (CBF) when autoregulation is defective or its limit is exceeded?
Increases CBF as a result of autoregulation impairment
What happens to cerebral blood flow when β-mimetic drugs, like norepinephrine with β1 activity, gain greater access to the brain parenchyma via a defective BBB?
Increase in cerebral blood flow
How does the administration of phenylephrine during cardiopulmonary bypass impact cerebral blood flow (CBF)?
Has no effect on CBF
How does phenylephrine administration affect regional cerebral oxygen saturation (rSO2) according to the text?
Modestly reduces rSO2
What is a reason why ephedrine did not reduce regional cerebral oxygen saturation (rSO2) like phenylephrine?
Maintains cardiac output
What impact did norepinephrine administration have on cerebral oxygen saturation according to the text?
Slightly reduced MCAfv and Sco2
Why is a modest reduction in Sco2 not considered evidence of impairment of cerebral oxygenation during vasopressor administration?
Sco2 measurements are sensitive to extracranial contamination
What is the primary mechanism by which dexmedetomidine primarily affects cerebral blood flow (CBF)?
Suppression of cerebral metabolic rate (CMR)
Which of the following accurately describes the effect of dexmedetomidine on cerebral blood flow (CBF) based on the text?
The reduction in CBF with dexmedetomidine is proportionate to the decrease in CMR.
Which drug is described as a significantly less specific and less potent α2-agonist compared to dexmedetomidine?
Clonidine
How did dexmedetomidine impact cerebral blood flow (CBF) in healthy human volunteers during investigation?
Reduced CBF by approximately 30%
What was observed about the relationship between middle cerebral artery flow velocity (MCAfv) and cerebral metabolic rate (CMR) under the influence of dexmedetomidine?
MCAfv decreased in parallel with a reduction in CMR
How does epinephrine affect cerebral blood flow (CBF) and cerebral metabolic rate (CMR) in nonanesthetized humans when the mean arterial pressure (MAP) does not substantially change?
Has no effect on CBF and CMR
What effect does dobutamine have on cerebral blood flow (CBF) independent of its impact on blood pressure?
Increases CBF by 20%
When the blood-brain barrier (BBB) is impaired, what is the effect of intracarotid norepinephrine on cerebral blood flow (CBF) and cerebral metabolic rate (CMR)?
Significantly increases CBF and CMR
How do β-agonists like epinephrine impact cerebral metabolic rate of oxygen consumption (CMRO2) when the BBB is permeable?
Increase both CBF and CMRO2
What is the interpretation regarding the effects of β-agonists on cerebral blood flow (CBF) and cerebral metabolic rate (CMR) when the blood-brain barrier (BBB) is injured?
Increases both CBF and CMR significantly
When administered to patients under hypotensive epidural anesthesia, how does epinephrine primarily impact middle cerebral artery flow velocity (MCAfv)?
Increases MCAfv
In nonanesthetized humans, what happens to cerebral blood flow (CBF) when intracarotid epinephrine is administered in doses that do not change mean arterial pressure (MAP)?
CBF remains unchanged
What effect does larger doses of epinephrine that resulting in an increase in MAP, have on cerebral blood flow (CBF) and cerebral metabolic rate of oxygen consumption (CMRO2)?
Both CBF and CMRO2 increase by approximately 20%
What is the likely impact of administering epinephrine to patients undergoing surgery under hypotensive epidural anesthesia on middle cerebral artery flow velocity (MCAfv)?
MCAfv increases possibly due to enhanced cardiac output
How is middle cerebral artery flow velocity (MCAfv) likely influenced when epinephrine is given to patients under hypotensive epidural anesthesia?
MCAfv increases potentially due to enhanced cardiac output
Which receptor is likely the mediator of the increase in cerebral metabolic rate (CMR) and cerebral blood flow (CBF) caused by larger doses of vasoactive drugs?
β1-receptor
In what scenario can β-Agonists lead to an increase in cerebral metabolic rate (CMR) and cerebral blood flow (CBF)?
When given In larger doses
What effect does esmolol have on seizures induced by electroconvulsive therapy (ECT)?
Shortens seizures
In patients undergoing craniotomy who become hypertensive during emergence from anesthesia, what effect is observed after the administration of labetalol?
Reduced CBF
What is the likely outcome when β-blockers are administered to patients with intracranial pathology?
No significant impact
which of the followings ikely to influence the β-blocker effects at time of β-blocker administration ?
Catecholamine levels or the status of the BBB or both
β-Blockers EFFECT on CBF and CMR.
either reduce or have no effect on CBF and CMR.
What is the predominant effect of dopamine on the normal cerebral vasculature when administered in small doses?
Slight vasodilation with minimal change in CMR
dopamine in high doses can act on alpha receptors which lead to systemic vasoconstriction. What is a characteristic of the cerebral circulation when dopamine is administered in doses up to 100 μg/kg/min?
no effect on cerebral circulation
Which receptor does fenoldopam act on, leading to systemic vasodilation and decreased arterial blood pressure?
DA1-receptor and α2-receptor
What happens to cerebral blood flow (CBF) when fenoldopam is administered to decrease systemic blood pressure?
15% reduction in CBF
Which region of the brain can experience increased CMR under the influence of dopamine administration?
Choroid plexus
patients arrive to the ER with focal cerebral ischemia and vasospasm, also known that he has hemodynamic dysfunction? which drug can be used to treat the vasospasm and also augment cardiovascular system and increase MAP?
Dopamine
which drugs are frequently used to treat acute hypertension in the neurologically injured patient population.
Calcium channel blockers.
which calcium channels are found in Cerebral vessels ?
L-type calcium channel.
What makes nicardipine a commonly used calcium channel blocker for perioperative blood pressure control?
Short half-life and easy titratability
What is the distinguishing feature of clevidipine ?
Ultrashort half-life due to rapid esterase-mediated metabolism
What effect does intravenous administration of nimodipine have on cerebral blood flow (CBF) in healthy humans?
Increases CBF by approximately 5% to 10%
What impact does nimodipine have on autoregulation when administered to human subjects?
Blunts autoregulation moderately
What is the primary effect of calcium channel blockers on cerebral vessels?
Inducing vasodilation of pial and cerebral arteries
Which calcium channel blocker has been shown to increase regional cerebral blood flow significantly after subarachnoid hemorrhage, provided mean arterial pressure (MAP) is maintained?
Nimodipine
WHAT is the most commonly used Calcium channel blockers for perioperative blood pressure control ?
Nicardipine
What determines the net impact of calcium channel blockers (CCBs) on cerebral blood flow (CBF)?
mean arterial pressure (MAP)
When mean arterial pressure (MAP) is maintained, what is the expected effect on cerebral blood flow (CBF) after administering calcium channel blockers?
Increase CBF
What role does systemic vasodilation play in the impact of calcium channel blockers (CCBs) on cerebral blood flow?
ependent on the extent of systemic vasodilation and MAP
What impact do vasoactive drugs have on cerebral blood flow (CBF) in the presence of calcium channel blockers (CCBs) if mean arterial pressure (MAP) is maintained?
Increase CBF
What is the impact of acute administration of Angiotensin II (AII) on the cerebral circulation?
Increases cerebral microvascular constriction without affecting CBF
Which statement regarding Angiotensin-Converting Enzyme Inhibitors (ACE inhibitors) and Angiotensin Receptor Blockers (ARBs) is correct?
They reduce arterial blood pressure but do not affect CBF
How do ACE inhibitors and ARBs affect the need for other vasopressors in the treatment of vasodilatory shock?
Reduce the need for other vasopressors like norepinephrine
What effect does Angiotensin II has on autoregulation and CO2 responsivity
autoregulation and CO2 responsivity appear to be maintained.
What is a key characteristic of the loss of synapses in the aged brain?
Considerably greater loss of synapses compared to myelinated fibers
What effect does aging have on dendritic spines in the brain?
Approximately 25% to 35% decrease in dendritic spines
How does aging impact cerebral circulatory responsiveness in healthy individuals?
Slightly reduced responsiveness to changes in Paco2 and hypoxia
In the aging brain, what happens to both cerebral blood flow (CBF) and cerebral metabolic rate of oxygen consumption (CMRO2) around the age of 80 years?
Both CBF and CMRO2 decrease by 15% to 20%
What is the primary impact of the loss of neuropil in the aging brain on cerebral physiology?
Reduction in both CBF and CMRO2
What is the approximate percentage of neuronal loss in a healthy aged brain according to the provided text?
10%
What consequence results from the loss of myelinated fibers in the aging brain?
Reduced white matter volume
In the normally aging brain, what is significantly greater compared to the loss of neurons?
Loss of synapses
This quiz covers the effects of systemic vasodilators like sodium nitroprusside, nitroglycerin, hydralazine, adenosine, and calcium channel blockers on cerebral vasodilation and cerebral blood flow. Learn about the differences in cerebral blood flow when induced by different hypotensive agents.
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