CNS Flashcards

1
Q

What is the cutoff for elevated ICP

A

> 15

normal 5-10
elevated 15
severe > 40

CPP = MAP - ICP

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2
Q

CPP is constant over what MAP range?

A

MAP 50 - 150

CBF constant

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3
Q

cerebral ischemia pressures

A
normal = CBF 40-60cc/100g/min  
neuro symptoms = 20- 30 
isoelectric eeg = 16 - 20 
Na/K pump failure, cytotoxic edema = 10 - 12 
irreversible brain damage < 10
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4
Q

what is cushing’s triad?

A

HTN
bradycardia
irregular respirations

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5
Q

What IV anesthestic increases CMR?

A

ketamine increases cerebral metabolic rate

everything else decrease CMR and CBF

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6
Q

what inhaled anesthetics increases CBF the most?

A

halothane / head
enflurane

the others don’t do it as bad
iso = des = sevo

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7
Q

effect of inhalational anesthetics on brain

A

increase CBF
decrease CMR

MAC 1 then CBF = CMR

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8
Q

PACO2 vs CBF curve?

A

linear between PaCO2 30 - 60

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9
Q

CBF gray matter vs white

A

Gray matter has increases CBF than white

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10
Q

hypothermia effect of CBF

A

CBF decreases 5-7% per deg C drop

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11
Q

What can you do during cardio-bypass or valve replacement

A

embolic risk to brain during CBP or valve change

  • hypothermia –> decreases CBF
  • burst suppression = isoelectric activity brain during hypoperfusion
  • normal Hct 32%
  • when warming maintain CPP
  • arterial filters
  • glucose control
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12
Q

spinal cord vertebral bodies

A
cervical 7 
thoracic 12
lumbar 5
sacrum 5
coccyx 4
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13
Q

spinal cord nerves

A
cervical 8
thoracic 12
lumbar 5
sacrum 5
coccyx 1
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14
Q

order of nerve blockade

A

sympathetic/PS: C, B fibers
A-delta,
A-beta
A-alpha

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15
Q

What is brown sequard?

A

damage to half spinal cord –> paralysis and loss of proprioception to IPSILATERAL side

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16
Q

What is brown sequard?

A

damage to half spinal cord

paralysis and loss of proprioception to IPSILATERAL side

contralateral loss pain and temperature

17
Q

anterior vs posterior spinal cord blood supply

A

1 anterior spinal artery –> ventral 2/3 spinal cord

2 posterior –> dorsal 1/3

18
Q

anterior cord syndrome

A

loss ipsilateral motor (ventral corticospinal)
loss contralateral pain/temp (lateral spinothalamic)

largest radicular artery = artery of adamkiewicz

don’t have good collaterals from T1-T4 and first lumbar segments –> prone to ischemia during cross-clamping or vascular occlusions

19
Q

what is autonomic hyperreflexia

A

injury at or above T6
flushing above
vasoconstriction below

20
Q

Brain waves

A
Alpha = Awake
Beta = Busy thinking
Theta = GETA 
Delta = Deep sleeping
21
Q

what contributes to increased latency?

A
hypothermia / hyperthermia 
hypotension 
anemia (Hct < 15%) 
hypoxia 
hypercapnea
22
Q

exceptions to decreasing amplitude/ increased latency

A

NO2 = latency stable, decreased amplitude,
etomidate = increased latency + amplitude
ketamine = increased amplitude
opioid = no change
muscle relaxant = no change

23
Q

what’s the first line therapy for organophosphate toxicity/exposure?

A

Pralidoxime

organophosphates = irreversible inhibition of ACh-esterase –> tons of ACh in NMJ

24
Q

PNS arises from what nerves?

A

CN 3, 7, 9, 10 + sacral segments

25
What are the risk factors for Postoperative cognitive dysfunction (POCD)?
- advanced age - lower education - h/o CVA w/o residual impairment
26
bainbridge reflex
right atrial wall senses stretch --> increasing HR | see in pregnant women
27
herning-breuer reflex
over-inflation of lungs --> reflex prevents further inspiration
28
neurogenic shock
loss of sympathetic function --> cannot oppose vagal stimulation --> bradycardia pts w/ acute spine injuries
29
what are important factors in level of spinal dose?
dosage baricity positioning
30
where does great radicular artery originate from?
T9-T12 blood supply to anterior spinal cord --> motor function different names for same vessel: artery of Adamkewitz, arteria radicularis magna, great radicular artery if anterior spinal cord syndrome --> loss of motor, pain, temperature
31
rank nerve fibers by sensitivity to local anesthetics
most sensitive B > A > C least
32
when doing an epidural, what factors increase spread?
volume positive airway pressure lateral/T-berg position increased age