Neuroanatomy (exam 1) Flashcards
(247 cards)
1
Q
The brain receives what % of cardiac output?
A
15%
2
Q
The brain receives how many ml of blood per 100 g of brain tissue per min?
A
50-65 mL
3
Q
Does hypothermia increase or decrease CBF?
A
Decreases CBF
4
Q
Does hyperthermia increase or decrease CBF?
A
Increases CBF
5
Q
Does CBF increase or decrease with age?
A
Decreases with old age
6
Q
What is the most powerful factor to increase CBF?
A
CO2
7
Q
True or False: A doubling of CO2 doubles CBF?
A
True
8
Q
HTN causes a right or left shift of the autoregulation curve?
A
Rightward shift
9
Q
Metabolically what occurs so that CO2 can cause an increase in CBF?
A
CO2 combines with water to form carbonic acid which forms Hydrogen.
The H-‘s are what cause vasodilation of cerebral vessels (causing an increase in CBF)
10
Q
The Brain uses O2 at a near constant rate, if CBF becomes insufficient to supply the needed amount of O2 what happens?
A
vasodilation occurs and CBF increases (known as autoregulation)
11
Q
Both CO2 and O2 can cause an increase in CBF but which one is the most powerful factor?
A
CO2 is the most powerful factor.
O2 as hypoxia is a potent stimulus.
12
Q
The cerebral blood flow is maintained fairly stable for a MABP of ?
A
50-150 (60-160)
13
Q
autoregulation shifts to the left with what perfusion problems?
A
hypoperfusion / cerebral ischemia
14
Q
autoregulation shifts to the right with what problem?
A
chronic HTN
15
Q
*Arteries that form the circle of Willis?
A
2 carotid and 2 vertebral arteries - which merge to form the Circle of Willis at base of brain.
16
Q
Three major components of the Intracranial contents?
A
Brain
CSF
Blood
17
Q
What are astrocytes and their function?
A
star-shaped non-neuronal cells that support and protect neurons as well as provide nutrition.
18
Q
Electrical stimulation of excitatory glutaminergic neurons leads to?
A
increase in intracellular calcium ion and vasodilation of nearby arterioles.
19
Q
Does arterial or venous BP fluctuate greatly?
A
arterial
20
Q
People with hypoperfusion/ cerebral ischemia, autoregulation is shifted to the left or right?
A
left
21
Q
Autoregulation is by 2 separate mechanisms, what are the two mechanisms?
A
Responses to mean blood pressure changes
Responses to pulsatile pressure (perfusion pressure– for example…decreased during CPB)
22
Q
When MAP rises acutely during strenuous exercise what happens so that vascular hemorrhage does not occur?
A
SNS constricts the large and intermediate-sized brain arteries enough to prevent the high pressure from reaching the smaller brain blood vessels. Thus, preventing vascular hemorrhages.
23
Q
Give me an example of global ischemia and focal ischemia?
A
Global = cardiac arrest Focal = localized stroke
24
Q
What is Penumbra?
A
an area of moderate ischemia peripheral to an area of greater ischemia, the penumbra area has compromised blood flow.
(immediate revascularization can save neurons in the penumbra)
25
most sensitive area of the brain for hypoxia/ischemia?
hippocampus (area for recent memories)
26
What is tPA used for?
window of use?
contraindications?
risk/side effects?
clot buster, reperfusion of an ischemic area of the brain.
3 hour window of use.
contraindications: hemorrhagic stroke, recent surgery.
Risks/side effects: cerebral hemorrhage
27
target glucose for treatment of cerebral ischemia?
target 180 mg/dl
28
Treatments for epilepsy?
Benzodiazepine
Barbiturates
Anti-epileptic (phenytoin)
29
What are most strokes caused by?
arteriosclerotic plaques that occur in one or more of the feeder arteries to the brain.
30
Most common arteries affected by Hemorrhagic strokes?
Middle Cerebral Artery
Posterior Cerebral Artery
Midbrain arteries
31
Entire capacity of cerebral cavity enclosing brain and spinal cord is about how much in mL?
1600-1700mL
32
CSF alone is how many mL?
150mL
33
Rate of CSF formation is about how much per day?
500-600mL/day
34
What is Coup, Contrecoup, and coup contrecoup?
Coup = contusion on the same side as the impact injury.
Contrecoup = injury to the opposite side as the site of injury.
Coup contrecoup = injury at the site of trauma and the opposite side of the brain.
35
What structure is responsible for drainage or reabsorption of CSF?
Arachnoid Villi
36
Normal CSF pressure in children is?
| Adults?
```
children = 3-7.5
adult = 4.5-13.5
```
Just need to know that children is less than adults.
37
What is normal ICP?
less than or equal to 20
38
What is the main cause of death after head injury?
Elevated ICP
39
Intracranial pressure curve, what does point 3 and 4 tell you?
At point 3, focal ischemia occurs. At point 4, global ischemia occur
40
Sustained elevation of ICP leads to?
brain herniation
41
Normally increases in volume (ICP) are initially well compensated, what points on the Intracranial pressure curve would this be?
1 and 2
42
*What is Cushings Triad?
increase ICP leads to reflex increase in MAP (hypertension), decrease in HR (bradycardia) and irregular respiration.
43
Intracranial Hypertension would be defined as?
ICP greater than 20 mmHg
44
What are some causes of intracranial hypertension?
mass lesion
hematoma
head trauma
45
herniation of the brain due to increased ICP will occur through what two structures?
tentorial notch
| foramen magnum
46
Intracranial hypertension will cause what to occur on the same side of the mass?
cranial nerve three compression on the ipsilateral side = fixed dilated pupil to the same side as the mass (also cushings triad)
47
Chronic intracranial hypertension will cause?
papilledema
48
Treatment of intracrainial hypertension?
ABCs
Intubation plus hyperventilation
Maintain PCO2 level 25-30ish mmHg
Mannitol
Sedation
Steroids
Slowly wean from ventilator
49
Glasgow coma score, tell me what each number range means?
Severe brain injury defined as 7 or less
Moderate injury = 8-12
Minor injury = > 13
50
Two techniques to monitor ICP today? (explain)
1…intraventricular (requires cannulation of ventricular frontal horn)
2…intraparenchymal (often held in place by bolt screw)
51
An increase in ICP can reduce what?
CBF
52
Cerebral blood flow and BP is maintained pretty constant over a wide MABP, what would that range be?
50-150
53
What does CPP measure?
Cerebral Perfusion Pressure (CPP)- Is actually what is measured as a surrogate for Cerebral Blood flow under conditions where stats are rapidly changing (i.e. ill person with increased ICP and possible herniation in progress)….
54
What measurement is the difference between MAP and the greater of ICP or CVP?
CPP
55
equation for CPP is?
MABP - ICP or CVP (whichever is greater)
56
What should the CPP range be, and what do the ranges mean?
CPP Goal- Maintain above 50-55
CPP < 40 considered critical
57
Difference between communication and non-communicating Hydrocephalus?
Communicating: Caused by blockage of fluid flow around base of brain or by blockage of arachnoidal villi
Fluid collects on the outside of brain and some collects inside the ventricles
Non-Communicating:Caused by block in aqueduct of Sylvius
Volumes of lateral and 3rd ventricle increase greatly
58
BBB is permeable to?
Water
CO2
O2
Most lipid-soluble substances
59
BBB is slightly permeable to?
Electrolytes: Na+, Cl, K+
60
BBB is impermeable to?
Plasma proteins
Non-lipid-soluble large molecules
61
What can cause the BBB to be more permeable? (like a break in the barrier)
```
Microwaves
Radiation
Trauma
Hypertension
Infection
```
62
What typically causes Brain Edema?
Usual cause is increased capillary pressure or damage to capillary wall that makes the wall leaky to fluid.
Starts a vicious cycle: edema decreases blood flow, causing ischemia, then more edema
63
Most of the Brains energy is supplied as what? and how long will that supply last?
Glucose
| only a 2 minute supply of glucose stored as glycogen in the neurons.
64
Most common first degree brain tumor is?
Astrocytoma
65
Do first degree brain tumors commonly or rarely undergo metastasis?
rarely
66
What type of prognosis and expectancy does astrocytoma have?
grave prognosis and less than 1 year life expectancy.
67
2nd most common first degree brain tumor? (arise from arachnoid cells external to the brain, slow growing)
Meningloma
68
Tumor found in the 4th ventricle, can cause hydrocephalus, poor prognosis, what is this tumor called?
Ependymoma
69
tumor that is relatively rare and slow growing?
oligondendroglioma
70
Most common prolactinoma, causes tunnel vision, hyper or hypo pitutarism can result?
Pituitary adenoma
71
3rd most common first degree tumor with schwann cell origin?
Schwannoma
72
What nerve is an acoustic schwannoma tumor localized to?
VII nerve
73
What test is diagnostic for seizures?
EEG
74
What type of seizure does not cause a loss of consciousness?
Focal (partial) seizure arise from discrete region, no loss of consciousness
75
causes of tumors in children, adults, and elderly?
Children- genetic, infection (febrile), trauma, congenital, metabolic
Adults- tumors, trauma, stroke, infection
Elderly- stroke, tumor, trauma, metabolic, infection
76
What is the major goal in neurosurgical anesthesia?
to provide adequate tissue perfusion to brain and spinal cord so that regional metabolic demand is met and to provide adequate surgical conditions (“a relaxed brain”)
77
In general IV anesthetics do what to CMR and CBF
| where most inhalation anesthetics cause what change to CMR and CBF?
IV anesthetics decrease cerebral metabolic rate (CMR) and CBF in parallel fashion….
Most inhalational anesthetics decrease CMR with an increase in CBF (cerebral vasodilation)
78
What CANNOT not be recommended in patients who have experienced stroke?
hyperventilation
79
Hypercapnia is what?
high CO2
80
what is hypocapnia?
low CO2
81
what CO2 concentration can dilate vessels in the normal area of the brain but not in the damaged (ischemic) area?
high or hypercapnic
82
what is intracerebral steal?
"stealing from the poor"
when blood flow is shunted away from an ischemic area to a normal blood flow area of the brain.
83
what CO2 concentration can divert blood flow from the normal area of the brain to an ischemic area?
low or hypocapnic
84
what is "reverse" cerebral steal/Robin hood effect?
"stealing from the rich to give to the poor"
when blood is diverted from a normal area of the brain to an ischemic area.
85
How can you induce the "steal" phenomena?
pharmacologically with anesthesia (not hyperventilation)
86
Anesthesia alters ICP through changes in what?
CBV (which appear to be proportional to changes in CBF, thus in ICP)
87
Intracerebral steal VS. reverse steal?
intracerebral = blood flow away from ischemic area.
reverse = blood flow to ischemic area
88
How are the smaller blood vessels in the brain protected when MAP rises acutely? (ultimately protecting against vascular hemorrhage)
SNS constricts the large and intermediate-sized brain arteries enough to prevent the high pressure from reaching the smaller brain blood vessels. Thus, preventing vascular hemorrhages.
89
Sensory CN are?
I olfactory, II optic, VIII vestibulocholear
90
Motor CN are?
III occulomotor, IV trochlear, VI abducen, XI accessory, XII hypoglasal
91
What 4 large arteries merge to form the circle of Willis?
2 carotid and 2 vertebral arteries.
92
------ is the basic functional cell of the CNS?
Neuron
93
Sensory or Motor neuron has multiple dendritic processes and constitutes the majority of the CNS.
Motor
94
What cell lines the roof of the 3rd and 4th ventricles of the brain and central spinal cord. They also form the choroid plexus which secretes CSF?
Ependymal cells
95
These cells develop into large macrophages that phagocytize neuronal debris?
Microglia cells
96
Forms the myelin sheath of axons in the brain and spinal cord and are capable of mylenating more than one axon?
Oligodendrocyte cells
97
This cell forms the myelin sheath of peripheral nerves?
Schwann cells
98
electrical stimulation of excitatory glutaminergic neurons leads to increase in ?
intracellular calcium ion and vasodilation of nearby arterioles.
99
Rate of CSF formation is constant, this makes what really important?
This makes drainage or reabsorption by arachnoid villi important!
100
blockage of CSF drainage or reabsorption by the arachnoid villi can be caused by?
tumor
hemorrhage
infection
101
what are the three signs of cushing's triad?
1. Irregular respiration
2. Bradycardia
3. hypertension
102
VAE is most often associated with what procedure?
posterior fossa procedures in the sitting position.
103
Intraoperative goals if a patient is suspected to have or does have a venous air embolism?
1. inform the surgeon immediately.
2. discontinue nitrous, increase 02 flows.
3. modify the anesthetic.
4. Have the surgeon fluid the surgical field.
5. provide jugular vein compression
6. aspirate the right atrial catheter.
7. provide cardiovascular support.
8. change the patients position.
104
most sensitive / noninvasive for VAE?
TEE
105
*Onset of insult when monitoring with evoked potentials would look like what?
decrease in amplitude and increase in latency
106
When an evoked potential changes what must you do?
you must assess the physiologic, anesthetic, and surgical environment to determine what has contributed to the change.
107
What does diffuse ischemia look like when monitoring evoked potentials?
What does mechanical injury or localized ischemia look like?
slow loss of response amplitude with an increase in latency = diffuse ischemia
fast losses of amplitude with minimal latency changes = mechanical injury or localized edema.
108
Medication commonly used for evoked potentials is opioids, why?
cause only mild depression of all responses
109
volatile anesthetics and N20 produces what kind of evoked potential changes?
decrease in amplitude and increase in latency
110
most commonly monitored evoked potential is?
SSEP
111
What evoked potential is used during CEA?
Cortical SSEP
112
What medication is acceptable to use with SSEP but not ok to use with MEP?
NMB are acceptable with SSEP
113
A change in SSEP corticol amplitude is most sensitive indication of what?
ischemia
114
SSEP can be used to monitor ischemia from what all factors?
```
VASOSPASM
retractor pressure
hypotension
clipping
hyperventilation
```
115
If SSEP is used during spinal cord surgery what can it identify?
mechanical or ischemic insult when they result in alteration or loss of transition through surgical field.
116
What evoked potential is used extensively for monitoring during surgery involving posterior fossa?
ABR (auditory brainstem responses)
117
When are visual evoked potentials used?
during craniofacial procedures, pituitary surgery, and surgery in the retrochiasmatic visual tracts and occiptal cortex.
(considered less useful in surgery)
118
What evoked potential is very common in spinal surgery?
MEPs bc it has a very good correlation with post-op outcome.
119
Preferred form of anesthetic delivery when using MEP?
TIVA is preferred
| (propofol with or without ketamine in combination with opioids) discuss with surgeon.
120
Name the CN 1-12
```
1 olfactory
2 optic
3 oculomotor
4 trochlear
5 trigeminal
6 abducens
7 facial
8 auditory
9 glossopharyngeal
10 vagus
11 spinal accessory
12 hypoglossal
```
121
Most common CN monitored during surgery is?
Facial nerve (CN 7)
122
stimulation of what two CN will cause CV changes?
CN IX and X
123
stimulation can cause potentially harmful head movement (sternocleidomastoid and trapezius activation)
CN XI
124
What CN monitoring is becoming common in skull base and anterior neck procedures?
X vagus nerve
125
Best choice muscle relaxant (during induction) for head injury with HTN and disturbed autoregulation?
Nondepolarizing neuromuscular relaxants do not appear to have clinically significant direct effects on CBF or CMRO2, provided MAP is not altered after administration
Rocuronium 1 mg/kg
126
How do IV anesthetics change CMR and CBF?
IV anesthetics decrease cerebral metabolic rate (CMR) and CBF in parallel fashion
127
How do inhalational anesthetics change CMR and CBF?
most inhalationals decrease CMR with an increase in CBF (cerebral vasodilation)
128
How do anesthetic agents change the affect of ICP?
by changing the rate of production and reabsorption of CSF/
129
Hyperventilation and head trauma, what is correct and incorrect?
Hyperventilation can rapidly control intracranial HTN, but prolonged and extreme hypocapnia (low CO2) from hyperventilation can result in a marked decrease in CBF in pts with head trauma (another reason it is C/I in CVA).
Only short duration of mild to moderate hyperventilation (hypocapnia) should be initiated (other pharmacologic/surgical intervention should be performed to control critical intracranial HTN)
130
"BEST" inhaled anesthetic for NEURO patients would be?
Isoflorane
131
cerebral vasodilators (capable of increasing ICP) usually depress metabolism EXCEPT for
N20
132
Why does N20 have restricted use in neurosurgical procedures?
N/V incidence among other properties
133
When N20 is added to volatile anesthetics it increases both what and what?
CBF and CMR
134
What gas has no direct vasodilating effect as well as the most dramatic increase in CBF and ICP when administered alone?
N20
135
Other name for Isoflurane?
Forane
136
What has Isoflurane been reported to do to whole brain metabolism?
reduce whole brain metabolism by half.
potent cerebral metabolic depressive effects.
137
Which gas has the only property to increase ICP mildly but can be prevented with hypocapnia?
Isoflurane
138
Which gas has the disadvantage of compound A renal toxicity?
Sevoflurane
139
What is the other name for Sevo?
Ultane
140
What surgical situation can make sevo undesirable to use?
prolonged anesthesia for neurosurgery with preexisting renal disease.
141
Which two gases may have neuro-protective effects similary to Iso? One is proven clinically and one is not...
proven clinically = Des
not proven clinically = Sevo
142
Why is ketamine a unique IV anesthetic?
increases both CBF and CMR while all other IV anesthetics decrease both. (also increases ICP)
(synthetic opioids are a possible exception, may slightly increase ICP)
143
what IV anesthetic has the effect to keep ICP the same or slightly increase?
synthetic opioids
144
True or False
| IV anesthetics decrease CBF and CMR due to vasoconstriction?
False, - Decrease in CBF by most is a result of reduced cerebral metabolism secondary to cerebral functional depression… not due to vasoconstriction
145
Does etomidate have CV side effects, does it change CMRO2, and what are it's adverse effects?
does not have CV side effects.
decreases CMRO2 like barbs
Adverse effects: adrenocortical suppression & frequent occurrence of involuntary muscle activity and seizure activity – use with great caution with pt having history of seizures
146
Should propofol be used in children?
Prolonged use may cause systemic acidosis and progressive cardiac failure and even death in children…use of prolonged infusion in children is UNJUSTIFIED
147
Propofol has dose related decreases in what and what?
| It also decreases what else?
dose related decreases in CBF and CMR02.
Also decreases ICP
148
What all does ketamine increase?
increases CBF, CMRO2, and ICP.
149
the markedly increase in ICP by ketamine can be blocked or attenuated by what?
induced hypocapnia, thiopental, or benzos
150
What does Versed do to ICP?
decrease or no change to ICP
151
Which is better at maintaining hemodynamic stability, versed or thipental?
Versed
152
Flumazenil and pts with impaired intracranial compliance?
Flumazenil (antagonist) also antagonizes effects of benzo of CBF, CMRO2, and ICP – use cautiously when reversing sedation in pts with impaired intracranial compliance
153
What opioid is used in neurosurgery with satisfactory results more so than any other?
Remifentanil which is fast on and fast off.
| alfentanil can also be used over fentanyl and sufentanil
154
Succinylcholine and use with neuro patients?
elevates ICP, may be prevented or decreased with pretreatment with NDMR.
Induced hyperkalemia is another concern with neuro patients and Sch. use
155
When would it be o.k. to use Sch in a neuro case?
emergency situation (full stomach/RSI/ difficult airway) with NDMB for defasciculating dose.
156
Histamine release by some NMB is an issue with neuroanesthesia patients, why?
Histamine can reduce CPP b/c of the increase in ICP caused by cerebral vasodilation and the decrease in MAP.
histamine = increased ICP and decreased CPP, MAP.
157
Atracurium and use with neuro-anesthesia patients?
clinical dose appears to have no significant effect on CBF, CMRO2, or ICP. However, high doses have potential release of histamine (so give slowly).
158
What is laudanosine?
Metabolite of atracurium (laudanosine) has been reported to cross BBB and cause seizures
159
Does cisatracurium produce or release laudanosine?
Produces and releases LESS laudanosine and histamine than atracurium
160
Vecuronium and neuro-anesthesia?
does not induce histamine release, nor does it change B/P or HR (often preferable)
161
Rocuronium and neuro-anesthesia?
rapid onset with lack of adverse activity such as histamine release, may be preferable to Sch. during RSI
162
what dose of lidocaine to prevents circulatory changes and an elevation of ICP during tracheal intubation, endotracheal suctioning, or after application of pin-type skull clamp or skin incision in patient undergoing craniotomy
1.5mg/kg
163
name an agonist that is a potent cerebral vasoconstrictor?
alpha agdrenergic agonist
164
dexmedetomidine (prexedex) in small doses does what to CBF, MABP, and ICP?
DECREASES CBF, MABP, and ICP
165
because of precedex having a quick onset and offset without resp. depression it may be advantageous for what procedure?
awake crani
166
autoregulation is impaired with what types of anesthetics and is NOT impaired with what anesthetics?
autoregulation is impaired with volatile anesthetics, especially at high concentrations, also by/with level of paCO2.
autoregulation is preserved by IV anesthetics even if used with hypocapnia.
167
pts with intracranial space occupying lesion will usually have what impaired?
autoregulation, so much so that sudden changes in blood pressure can produce ischemia or brain edema.
168
what are barbiturates known to do in a patient with focal ischemia (stoke)?
neuro-protective properties
169
Barbiturates are a - Favorable drugs provided that CV stability is maintained. However, prolonged use results in accumulated effects (slow metabolism)…other IV agents may be more appropriate, what drug would this be?
propofol
170
Most appropriate fluid for maintenance in neuro patient under general anesthesia?
Normal Saline
171
should dextrose solutions be infused for patients at risk for an ischemic event?
NO! unless for the treatment or prevention of hypoglycemia.
172
As a general rule what to types of IV fluids should be avoided in the neuro patient?
hypo-osmolar and dextrose containing solutions.
173
Fluid administered during craniotomy can be what types?
iso-osmolar crystalloid / usually LR or NS
174
True or False:
| Ideally, IV fluid be administered at rate to increase CO but avoid excessive fluid resuscitation
False,
| Ideally, IV fluid be administered at rate to MAINTAIN CO but avoid excessive fluid resuscitation
175
What type of drug is Mannitol?
osmotic diuretic - most commonly administered hyperosmolar solution.
176
infusions of Mannitol may initially cause what? but then the end result should be what?
During infusion it may increase ICP transiently (vasodilation of cerebral vessels in response to sudden increase to increased osmolality) and then it may (should) decrease ICP by movement of water from brain interstitial and intracellular spaces into vasculature - end result
177
Rapid IV dose of mannitol would be?
0.25-1 g/kg
178
hetastarch and use in neurosurgery?
limited use in neurosurgery due to sporadic cases of cerebral hemorrhages being reported
179
what is the "do not exceed" dose for dextrans?
Do not exceed 20 ml/kg if 24 hours
180
what two volume replacements are not recommended due to coagulopathy in a patient with head injury?
hetastarch and dextran
181
OVERALL what solution is the first choice volume resuscitation of trauma pts with head injuries?
isotonic crystalloid solution
| fresh whole blood would be nice, but most blood banks do not have this available
182
trauma patient with head injury, what is the ideal resuscitaion with hypovolemia and ongoing blood loss?
Fresh whole blood!
| but few blood banks have this available.
183
NS is good choice for replacement bc it is inexpensive and it can be give with PRBC, but if large volumes of NS are given for resuscitation what could occur?
possible to develop hyperchloremic acidosis.
184
how much potassium does LR contain?
4 mEq of potassium
185
No single IV solution is best suited for pt at risk for intracrainial HTN but the use of what solution is widely accepted?
iso-osmolar crystalloids
186
Tell me why the BBB has such low permeability?
due to "tight junctions" that join the endothelial cells of the brain's tissue capillaries.
187
Intracranial tumors, the majority of adult 1 degree tumors are --- and the majority of childhood 1 degree tumors are ---?
adult = SUPRA-tentorial
child = INFRA-tentorial
188
Most prudent approach to CEA maintenance is?
NORMOcapnia
189
What remains the "gold standard" of choice for stroke prevention?
CEA
190
To increase CPP during carotid cross clamping what will you have to do?
induce HTN
191
If a patient has good collateral flow then what would you maintain their blood pressure at?
normal pre-op range may be acceptable or increase to 20% above normal.
192
Pts. with poor collateral flow may need an increase of blood pressure ? how much above baseline?
20-30%, discuss with surgeon.
193
how much does CBF change for ever 1 mm Hg change in PaCO2?
CBF 1-2 ml/ 100g / min
194
carotid arteries provide what % of cerebral blood flow? vertebral arteries are what %?
carotid arteries provide 80% and vertebral arteries provide 20%
195
CEA, open artery exposure causes firing down the myelinated A-type and C-type fibers of the ---- nerve to the nucleus tractus solitaris?
glossoharyngeal
196
Open CEA creates a carotid chemo-response that overall causes onset of what?
Overall, causes onset of tachycardia and severe hypertension and thus increases in afterload and myocardial oxygen demand
197
Pts. to have Carotid Angioplasty stents are medicated with what two meds 3-5 days prior to procedure?
ASA and clopidogrel
198
If a carotid stent is to be placed stystemic heparin is given IV and then what test is performed?
ACT which should be confirmed at about 2x baseline value.
199
what typically occurs after carotid cross-clamping?
HTN- be prepared to treat.
200
When is the heparin administered for CEA?
Before carotid cross-clamping the heparin is administered.
201
How long after Heparin administration do you notify the surgeon?
3 min.
202
CEA you want a deep emergence or quick emergence?
quick emergence, important to assess neurological function quickly
203
What would be considered a desired stump pressure?
| What stump pressure would correlate with cross-clamp intolerance?
desired = greater than 50/60
stump pressure less than 25 mm Hg correlates with cross clamp intolerance. (inadequate CPP)
204
What is the gold standard for imaging evaluation with AVMs?
DSA
205
A patient presents with an AVM, is this an emergent surgery?
No, unless there is a rupture. They are usually scheduled and delayed.
206
Frontal lobe controls?
personality
207
Parietal lobe controls?
movement of the arms and legs
208
Temporal lobe controls?
speech, memory, and understanding
209
Occipital lobe controls?
vision
210
Cerebellum controls?
walking and coordination
211
Ventricles control?
secretion and cerebrospinal fluid
212
The brainstem controls?
the pathway for all basic functions of the body, (HR, respiration)
213
Best anesthetic plan for large tumor resection under SSEP and MEP monitoring?
Propofol is most commonly used when SSEP and MEPs are being monitored
(remember SSEP can use NMB but not MEP)
214
Laplace gas law states?
states that the tension within the wall of a sphere filled to a particular pressure depends on the thickness of the sphere. Consequently, even at a constant pressure, the tension within a filled sphere can be decreased simply by increasing the thickness of the sphere's wall.
215
Boyles law
a law stating that the pressure of a given mass of an ideal gas is inversely proportional to its volume at a constant temperature.
216
What should be avoided in patients who have ischemic cerebrovascular disease?
prolonged hyperventilation (discuss with surgeon)
217
mild decreases in temp. can do what for a neuro patient?
provide neuroprotective effects.
218
What is triple H therapy typically used for?
vasospasm following aneurysmal subarachnoid hemorrhage
219
What is Triple H therapy simply?
Hypervolemia, hypertensive, and hemodilution therapy “triple H therapy”
220
Hypervolemia in triple H therapy means?
Increase fluid to CVP around 10 mm Hg or PAWP 12-20 mm Hg, may use colloids (albumin) as well as crystalloids, avoid hetastarch and dextran solutions
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HTN in triple H therapy means?
use vasopressors (dopamine, dobutamine, phenylephrine), titrate until signs of vasospasm reversal or to maximum of 160-200 mm Hg systolic in pt whose aneurysm has been clipped, if not clipped, increase systolic only to 120-150 mm Hg (HTN must be maintained until vasospasm has resolved)
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Hemodilution in triple H therapy means?
based on correlation of hematocrit and whole blood viscosity, as Hct and viscosity diminish, CVR decreases and CBF increases; 33% provides optimal balance b/w viscosity and O2-carrying capacity (some surgeons allow 27-30)
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Typically during deliberate hypertension in triple H therapy the systemic blood pressure is raised above baseline by what percentage?
(this would be in absence of some direct outcome measure such as resolution of ischemic symptoms or imaging evidence of improved perfusion)
30-40% above baseline
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What is the first line agent for deliberate hypertension?
Phenylephrine
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Surgery time and TPA administration?
TPA can’t be given within 2 weeks of surgery or trauma patient
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PCI should be perfomed in what time frame?
90 min.
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What is Trigeminocardiac reflex and what is the treatment?
Pts undergoing surgery may experience bradycardia caused by activation of the trigeminocardiac reflex.
Treatment is anticholinergics!
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Right sided cath. is typically performed for what reason?
diagnostic
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Left sided cath. is typically performed for what reason?
performed from brachial cut down or more commonly through femoral artery * BOARDS*
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what can you give to a patient who has contrast agent reactions? and when would you give them these meds?
treated with steroids, antihistamines and H2 blockers prior to the procedure (treat the night before and morning of)
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severe contrast induced reactions would be?
Cardic shock
Resp. failure
Cardiac arrest
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What are the irreversible anticoagulants?
ASA
clopidogril
(direct thrombin inhibitors are SLOWLY reversible)
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angioplasty with stenting almost inevitably will cause bradycardia... what will be done in order to prepare for this?
(inflation of the balloon can cause bradycardia)
could include placement of transcutaneous pacing leads (stimulation to carotid body stimulation).
atropine or glyco may also be used to mitigate the bradycardia
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What is NOT an indication for ablation?
If you are a street drug user (drug abusing life style)
| know that not liking drug side/effects is a reason for ablation
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What is the advantage of using NEWER radiologic contrast media over old contrast media?
Newer = lower osmolor load and less neurotoxic
the lower osmolor load preserves intravascular volume in the event of an allergic crisis.
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Predicting factors for a protamine allergy?
NPH insulin allergy
prior vasectomy
(fish sperm allergy lol)
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40% of people's SA node is not perfused by the R coronary artery but by which artery?
Left Circumflex artery
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Posterior fossa surgery, of the meds below which would you avoid?
Benzos
antihypertensives
corticosteroids
fentanyl
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fentanyl
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acute hyperventilation - what is going on with your potassium?
transient decrease in potassium (goes into cell)
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neuro patient should not be sedated without what in place first?
secure airway
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Trauma patients, what do you need to have cleared before you intubate?
C SPINE CLEARANCE
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Is there any difference in older and newer radiologic contrast media for causing anaphylactoid reactions?
NO
| newer ones have lower osmolor loads and less neurtoxic
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what anticoagulant is primarily hepatic metabolism?
Argatroban
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what is the half life time for Lepirudin, bivalirudin, and synthetic derivatives?
40-120 minutes
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what is a negative about the anticoagulant Abciximab (Reopro) ?
increase likelihood of major bleeding due to long duration and potent effect.
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DTI and antiplatelet agents, do they have antidotes?
No
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When you are making a patient hypotensive on purpose what meds do we typically use?
nicardipine or sodium nitroprusside
