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Anesthesia: Basic > CNS > Flashcards

Flashcards in CNS Deck (32):
1

What is the cutoff for elevated ICP

> 15

normal 5-10
elevated 15
severe > 40

CPP = MAP - ICP

2

CPP is constant over what MAP range?

MAP 50 - 150
CBF constant

3

cerebral ischemia pressures

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

4

what is cushing's triad?

HTN
bradycardia
irregular respirations

5

What IV anesthestic increases CMR?

ketamine increases cerebral metabolic rate

everything else decrease CMR and CBF

6

what inhaled anesthetics increases CBF the most?

halothane / head
enflurane

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

7

effect of inhalational anesthetics on brain

increase CBF
decrease CMR

MAC 1 then CBF = CMR

8

PACO2 vs CBF curve?

linear between PaCO2 30 - 60

9

CBF gray matter vs white

Gray matter has increases CBF than white

10

hypothermia effect of CBF

CBF decreases 5-7% per deg C drop

11

What can you do during cardio-bypass or valve replacement

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

12

spinal cord vertebral bodies

cervical 7
thoracic 12
lumbar 5
sacrum 5
coccyx 4

13

spinal cord nerves

cervical 8
thoracic 12
lumbar 5
sacrum 5
coccyx 1

14

order of nerve blockade

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

15

What is brown sequard?

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

16

What is brown sequard?

damage to half spinal cord

paralysis and loss of proprioception to IPSILATERAL side

contralateral loss pain and temperature

17

anterior vs posterior spinal cord blood supply

1 anterior spinal artery --> ventral 2/3 spinal cord
2 posterior --> dorsal 1/3

18

anterior cord syndrome

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

what is autonomic hyperreflexia

injury at or above T6
flushing above
vasoconstriction below

20

Brain waves

Alpha = Awake
Beta = Busy thinking
Theta = GETA
Delta = Deep sleeping

21

what contributes to increased latency?

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

22

exceptions to decreasing amplitude/ increased latency

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

23

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

Pralidoxime

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

24

PNS arises from what nerves?

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