Neurosurgery Flashcards

Cerebrospinal fluid
Terms Definitions
gyri are
suolci are
shallow depressions
...PACO2 increases blood volume
..PACO2 caused increased JVD
dosing of nitro
1-10 ug/kg/min
anterior cerebral circulation originates from the
carotoid artery
disadv. of labetelol
limited efficacy bronchospasm
cmro2 generally parallels
cortical electrical activity
CN V is
the trigeminal nerve
mode of action esmolol
a adrenergic blockade
mode of action of trimethephan
ganglionic blockade
volitile anes. dilate cerebral vessels and impair a dose dependent manner
some studies suggest that optimal cerebral oxygen delivery ma occur at hematocrits of
adv. labetelol
reducing probability of adverse effects
C2 is also known as
the axis
relative contraindications for induced hypotension
ischemic cerebrovascular disease
glasgow coma scale best verbal response
5 oriented
nicardipine dosing
begin 5 mg/hr infusion, total 15
with the exception of...all iv agents have little effect on or reduce CRMO2 and CBF
in adults normal csf production is
21 mll/hr
...of ADH results from pressure placed by a tumor on the pituitary
luxury perfusion
increase CBF, with decrease in metabolic deman
..pot are mos effected by anes
visual evoked
the most important extrinsic influences on cbf are
respiratory gas tension
how many vertebrae in the crvical region
the largest portion of the brain ithe
a herniation of the subarachnoid space into the surrounding tissues is a
des and sevo produce a burst suppresion pattern at
high doses
Grade IV aneurysm
stumor, mild to moderate hemipharesis, early decerbation, mild vegetative distirbance
treatment for pituitary apoplexy
Treatment includes corticosteroids and surgical decompression
The part of the intervertrbral disk which herniates is the
nucleous pulposis
Obstruction in the flow of CSF can result in
how do you test CNVIII (8)
cover one ear
What techniques are instituted during aneurysm
surgery to "slack" the brain and facilitate dissection?
Hyperventilation, osmotic diuretics (mannitol), barbiturate administration, and CSF drainage provide a "slack" brain and help facilitate dissection.
Grade II aneurysm
moderate to sever ha, w/ nuchal rigidity, no neurological defecit other than cranial palsy
cerebral blood flow is directyly prop to pac02 between
20 and 80
treat intravascular air during VAE by
aspirate right catheter
discontinue n20
increase fio2 to 1.0
pressor intotropes
chest compression
increased JVD caused evidenced by the vent
increased airway pressures
iso is the only vol anes that can produce..eeg at high clinical doses
hypotension can ...cerebral blood volume as cerebral blood maintain blood flo
hypotension can increase cerebral blood volume as cerebral vesels dilate to maintain blood flow
which nerve is the optic nerve
cranial nerve 2 (II)
the sytem for the nerves is the
peripheal nervous system
A removal of a piece of cranial bone is known as &
which nerve is responsible for visceral pain and sensations
CN X (10) vagus
Which nerve is responsible for the facial muscles
CNVII (7) facial
the thin web like covering of the brain is the
arachnoid mater
intracellur Ca ..during ischemia
increases because of failure of atp dependent pumps to either extrude the ion extracellularly or into intracellular cisterns, increases intracellular na conc and release of excitatory neurotransmitter glutamate
during rupture of cerebral aneurysm (3)
fio2 100
reduce blood flow
give blood
symptoms of non functioning pituitary tumors
Symptoms include headache, impaired vision, cranial nerve palsies, increased ICP and hypopituitarism
rapid changes in plasma electrolyte concentrations and secondarily osmolality produce a
transient osmotic gradient betwen plasma and the brain
Grade I anurysum is marked by
slight nuchal rigidity w/without asymptomatic headache
which nerve is CNVI
(6) abducens for eye movement (lateral rectus) motor
which nerve is responsible for sense of hearing and equilibruim
CN VIII (8) Vestibulecochlear
hydrocephalus is
a bui;ld up of CSF in the ventricles due to an obstruction of narrowing impeding flow to the spinal cord
Which nerve is responsible for the sense of smell
Cranial nerve 1 (I)
What IV solutions should not be used for a craniotomy patient? Why?
Dextrose (glucose) containing solutions should be avoided. Hypertonic glucose in plasma initially decreases intracranial pressure by exerting an osmotic force and pulling water into the vasculature; but there will be a rebound increase in ICP as glucose is metabolized in brain cells, thereby decreasing osmotic pressure and pulling water from the vasculature to the brain
improve cerebral venous drainage (3)
head up, no peep, reduce inspiratory time
the system that prepares the body for emergencies
is the sypmathetic system
what happens when the nucleus pulposis extrudes thru the annulus of the cervical disc
herniation occurs which causes compression of the spinal cord ( surrounding nerves & their roots
the treatment for craniosynostis is
craniectomy (removal of a peice of bone )
List seven causes for disruption of the blood brain barrier.
The blood-brain barrier can become disrupted by acute hypertension, osmotic shock, disease, trauma, tumor, irradiation, or ischemia.
When using a hypotensive technique during a craniotomy, what happens to blood flow to ischemic and non ischemic regions of the brain? What is this shift in blood flow called?
Vessels in the ischemic regions are already maximally dilated. When there is a decrease in blood pressure produced by the hypotensive technique, the normal cerebral arteries dilate resulting in a shunting of blood away from the ischemic region. This is the intracerebral steal syndrome. This phenomenon is also called luxury perfusion
ventilation for lower ICP
PA02 at 100 mmg h, Pac02 35 and minimal intrathoraci pressures
methods at pre induction to reduce ICP
avoid head flexion, avoid JVD compression, head straight, hyperventilate on demand
movement of a given substance across the bb b is governed by
size, charge , lipid sollubility, degree of protein binding
the proximal end of a VA/VP shunt enters the
lateral ventricle of the brain
which nerve is the vagus, is it sensory or motor
CN X sensory & motor
What is the main anesthetic goal for a patient with a cerebral aneurysm?
Maintain or decrease cerebral perfusion pressure and transmural aneurysm pressure. Transmural pressure is the difference between mean arterial pressure (MAP) and intracranial pressure (ICP). An increase in MAP or a decrease in ICP will increase transmural pressure, which could lead to rupture of the aneurysm
What should be done prior to incision for opening the dura during intracranial aneurysm surgery to provide a "slack" brain?
Reduce intracranial pressure slowly to "relax" the brain. Diuretics (Lasix, mannitol) and head-up position may be helpful in this regard
decreases is CPP result in cerebral ...whereas ...result in....
decreases in cpp results in cerebral vasodilation where as increases results in vasoconstriction
most anes produce a..pattern on the eeg consisting of
most anes produce a biphasic pattern on the eeg consisting of initial activation followed by a dose dependent depression
Which nerve is abducens what is its function and how is it tested
CNVI (6). eye movement (lateral rectus) motor, move eye
How do you test the trigeminal nerve is it sensory or motor, which nerve is it
CNV, mixed, pinch skin & chew.
Which nerve is the trochlear, what is its function and how is it tested
CNIV (4) eye movement (superior oblique), test muscles by looking in opposite direction
to release the median nerve in carpal tunnel you
cut the transverse carpal ligamnet (transverse retinatum) s shaped incision required to prevent contracture
State 4 steps to take (hint: 3 drugs, 1 action) for anesthetic induction and intubation for the patient undergoing cerebral aneurysm repair
Anesthetic induction for the patient undergoing cerebral aneurysm repair should be slow and deliberate. (1) Anesthesia may be induced with either thiopental (3-5 mg/kg), propofol (1.5-2.5 mg/kg) or etomidate (0.5-1.0 mg/kg). (2) After loss of consciousness and apnea, care must be taken to maintain a normal PaCO2 and to avoid extreme hyperventilation. Vigorous hyperventilation will lower PaCO2 decreasing CBF. This may lower ICP to such a degree that if MAP is maintained or increased, transmural pressure will increase, leading to rupture of the aneurysm. (3) Fentanyl (3 to 5 mcg/kg), sufentanil (0.5 to 1.0 mcg/kg),
or remifentanil (0.25 to 1.0 mcg/kg) can be added 3-5 minutes before laryngoscopy to blunt the hemodynamic response. Isoflurane/desflurane/sevoflurane is added to deepen the anesthetic. (4) Approximately 90 seconds before laryngoscopy, lidocaine (1.5 to 2.0 mg/kg) or esmolol (0.5 mg/kg) can be added to further blunt the hemodynamic
response to intubation
What is the goal of deliberate (controlled)hypotension during surgery for cerebral aneurysm?
The goal is to maintain or reduce transmural pressure. Transmural pressure (TP), the pressure gradient across the wall of the aneurysm, equals mean arterial pressure (MAP) minus intracranial pressure (ICP). TP =MAP - ICP. Reducing transmural pressure decreases the likelihood of
aneurysm rupture.
What is the goal during induction for the patient who has an intracranial aneurysm?
The goal is to prevent an excessive, prolonged elevation in blood pressure that predictably occurs in response to direct laryngoscopy and tracheal intubation.
effect of pac02 on cbf is almost immediate and is thought to be secondary to
changes in pH of CSF and cerebral tissue
which nerve is the hypoglossal what is its funcyion and how is it tested
CN XII, (12) muscles of the tongue (motor) move tongue
which nerve is the olfactory nerve and how do you test it
CNI you check one nostril at a time, sensory nerve
CPP is between
the axis is
prostoglandin E dosing
.1-.65 ug/kg/min
increased ICP causes herniation and...perfusion pressure
Lumbar spondylosis is
advanced disc disease
dosing emolol
.2-.5 mg/kg/min loading dose
50-200 mcg /kg/min
adv. of nitro
rapid onset, offset, titration
marked abnormalities in serum sodium or glucose should be corrected
prostoglandin E disadv
slow offset, bradycardia, hyperthermia
labetalol mode of action
a/b adrenergic blockade
cbf changes ...per 1 degree C
which nerve is CN xII (12)
rebound hypertension is common after
sodium nitroprusside use
adv. of nicardipine
rapid onset, decreased reflex tachycardia
disadv. of nitro
ncreased ICP, rebound hypertension, increased pulmonary shunting, coagulation abnormalities
potential vasodilators are
n20, volitiles, calcium chanel blockers, nitro
disadv. of trimethephan
histamine release, cerebral compromise w/map below 55, decreased pseudocholinesterase
prostoglandin E adv
rapid onset, decreased reflex tachycardia, stable CBF
most sensative method to indicated vae
transesophageal echo
..has the greatest effect of vol. anes. on cerebral blood flow
Grade III aneurysm
drowsiness, confusion, mild focal defecit
how many bones in the lumbar region
which nerve is responsible for movement ofthe trapezuis muscle (shoulder)
CNxi (11)
pituitary tumors are two types
non functioning and hypersecreting
osmotic diuretics to decreased ICP
mannitol and hypertonic saline
during ischemia, intracell ..increases and intracel...decreases
k dec, na inc
volitile anes. alter both the..and ..of csf
formation and absorption
cranial vault is composed of...,...,... by %
brain 80
blood 12
adv of sodium nitro
rapid onset offset and titration
blood flow changes approx per mmhg change in paco2
1-2 ml/100g
Gray matter is
a large collection of cell bodies
lesions occupying space are (4)
hematoma, hydrocephalus, Tumor, Abcess
the common treatment for decompression of a nerve root due to an extruded disc fragment is
laminectomy & discectomy
what is the connective tissue of the brain
a VP shunt is
a ventricularperitoneal shunt, directs excess CSF away from barian into peritoneal space
the space between the aracnoid mater and the pia mater is the
subarachnoid space
crmo2 is greatest in
gray matter of the cerebral cortex
after controlling hemmorghage after cerebral aneurysm rupture..
cerebral preservation (elevate blood pressure, barbituates/isoflourane)
reduce edema (mannitol csf/drainage)
post op (controlled ventilation/monitor ICP)
least sens. method to detect VAE
increased end tidal n20
during rupture of cerebral aneurysm, reduction of blood flow is accomplished with
ipsilateral carotoid artery compression, sodium nitro
the longitudinal fissure divides
the two hemispheres of the cerebrum
white matter is
a collection of bundles of axons covered in a protective sheath called myelin
which nerve is responsible for peristalsis of bowel
CN X (10) vagus
which nerve is responsible for peristasis of ureters
CN X (10) vagus
During posterior fossa surgery, bradycardia and hypotension suddenly develop. Why?
Bradycardia and hypotension may occur if either the glossopharyngeal or the vagus nerve is stimulated
considerations related to posterior fossa surgery
VAE, hemodynamic effects r/t sitting position, pardoxic air embolism, hemondynamics effects of brain stem and cranial nerve manipulation, quadrapalegia, microglossia, pneumocephalus
during anurysmal dissection blood pressure regulation requires
decrease blood pressure to lower limits of autoregulation w iso or sodium nitro
brain glucose consumption is
5/mg/100 g/min of which 90% is metabolized aerobically
pituitary apoplexy is
Pituitary Apoplexy is a term used to describe sudden enlargement of the pituitary caused by hemorrhage or infarction of the piituitary caused by the tumor
fluids used to ensure lower ICP
.9NS Hes 6% not LR
during VAE prevent further air entry by
flooding field
avoid JVD compression
lower patients head
what is a astrocytoma
a malignant growth (tumor) in the brain (intracerebral), the most common tumor
which nerve is responsible for the posterior 1/3 of tongue
Cn IX (9) Glossopharngeal
the layer of nuerons on the surface of the brain is known as the
cerebral cortex
The autonomic nervous sytsme is responsible for
involuntary responses (connects the CNS to visceral organs )
the myelin sheath is found in which matter
the white matter
What is the standard regimen for treating cerebral vasospasm?
Standard treatment of cerebral vasospasm in the United States includes a regimen of a calcium channel blocker (usually nimodipine) and "Triple H" therapy (hypertensive, hemodilution & hypervolemic therapy).
State two reasons why elective (controlled)
hypotension is extremely useful for aneurysm
(1) Decreasing mean arterial pressure reduces transmural tension across the aneurysm, making rupture (or rebleeding) less likely and facilitating surgical clipping; (2) controlled hypotension can decrease blood loss and improve visualization in the event of bleeding
most commons hormone secreted with hypersecreting pituitary tumor
The most common hormone hypersecreted is Prolactin, followed by Growth Hormone followed by ACTH (Adrenocorticotropin).
..produces the greates depression in CMR and ..has the lest
iso the most, hal the least
the somatic nervous sytsem is responsible for
voluntary movement (it connects the CNS to the skin and skeletal muscles0
how does CSF flow thru the ventricles
lateral ventricles - intraventricular canal (foramen of monroe) - 3rd ventricle - aqueduct of slyvuis - 4th ventricle - foramane of magdie & foramen of lutska - sub arachnoid space
which nerve is the vestibulecochlear and what is it function
CNVIII sense of hearing and equilibruim, Sensory
What are the anesthetic goals for intracranial aneurysm surgery?
The anesthetic goals for intracranial aneurysm surgery are to avoid aneurysm rupture, maintain cerebral perfusion pressure, and to provide a "slack" brain.
Mean arterial pressure should be maintained at what level during controlled (deliberate)hypotension for surgery for clipping of a cerebral aneurysm?
MAP is usually maintained between 60 and 70 mm Hg (Morgan and Mikhail). The minimum MAP during controlled hypotension for clipping of a cerebral aneurysm is 50 mmHg (Yao and Artusio). Further reductions in MAP may be produced for short periods of time. The use of controlled hypotension during surgery for cerebral aneurysm is controversial (Miller, Barash).
limiting iso to ..mac and halothane to..mac decreased anes induced changes to evoked pot
iso .5 mac...hal to 1 mac
increases in blood pressure can ...cererbral blood volume because autoregulation induces...
increases in blood pressure can reduce cerebral blood volume because autoregulation can induce vasoconstriction in order to main CBF
acute hypotonicity of plasma results in
net movement of water into the brain
what is the purpose of a laminectomy/hemilaminectony
surgical approach for a herniated disk, spinal compression or spinal cord tumor, lamina are removed to expose the spinal cord & or nerve roots
a blood clot in or around the brain can be caused by
trauma, untreated hypertension, ruptured artery and aneurysm or AV malformation
association fibers in thewhite matter transmit impulses
to specific location within the same hemisphere
Why is isoflurane beneficial during a neurosurgical
case using controlled (deliberate) hypotension?
Isoflurane enhances the effects of the commonly used hypotensive agents. In addition, isoflurane (the only volatile anesthetic recommended for production of deliberate hypotension) blunts the stress-response evoked by
deliberate hypotension, and, in addition, pulmonary shunting is not increased
What can happen to ICP when isotonic IV fluids are administered to a patient with a disrupted blood-brain barrier (BBB)?
ICP can increase. The blood-brain barrier (BBB) normally impedes the flow of ions such as sodium, potassium, magnesium and calcium
barb have four major actions on the cns
hypnosis, depression of CMR, reduction of CBF due to increased Cerebral vascular resistance, 4) anticonvulsant activity
the valve on a VA/VP shunt is places
under the sclap, behind the ear
What is the rationale for triple H therapy?
Triple H therapy is intended to increase cerebral blood flow in brain areas that have been rendered ischemic by intense vascular narrowing. Although normally an increase in cerebral blood flow would not result from an increase in blood pressure, when there is vasospasm, the vascular bed
becomes passive. Therefore, increasing perfusion pressure by increasing intravascular volume or by systemic administration of vasoactive drugs may reverse symptoms of cerebral ischemia
which nerve is CNVII, where areas does it innervate & how is it tested
facial nerve (7) anterior 2/3 of tongue, & facial muscles, mixed, wrinkling, grimcing etc
What is the incidence of cerebral aneurysms in North America? Subarachnoid hemorrhage?
One in 50 persons (2%) has a cerebral aneurysm and one in 8,000 (less than 0.05%) has a subarachnoid hemorrhage
which nerve is the optic nerve and how do you test it?
CNII is tested with the snellen chart
What is the concern if the patient is to undergo
resection of a posterior fossa tumor located at the floor of the fourth ventricle?
Resection of tumors in the floor of the fourth ventricle may damage respiratory centers and necessitate mechanical ventilation postoperatively
what is the purpose of a spinal tap (lumbar punture)
check for the origin of a infection (viral or bacterial) or to take a culture
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