Neuro Anesthesia

Question 1

3 major components of the IC contents:

Answer 1

• 1- brain
• 2 – CSF
• 3 – blood

Question 2

insert circle of willis image

Answer 2

• know where it starts
• branches
• where it goes

Question 3

Blood flow supplied by

Answer 3

4 large arteries -

2 carotid and 2 vertebral arteries - which merge to form the Circle of Willis at base of brain

Question 4

the brain is enclosed by the skull except for the foramen magnum. hence, the Foramen magnum is a site of

Answer 4

herniation

Question 5

Arteries arising from circle of Willis give rise to

Answer 5

pial arteries,

which branch out into smaller vessels called penetrating arteries and arterioles

Question 6

Normal Rate of Cerebral Blood Flow

Answer 6

-50-65ml / 100 Gm of brain tissue / minute

o 750-900 ml/min for entire brain

Question 7

Cerebral Blood flow is what % of CO?

Answer 7

15% of cardiac output

Question 8

The most powerful factor of CBF:

Answer 8

CO2

Question 9

Doubling CO2 does what to CBF?

Answer 9

doubles CBF

Question 10

what does hypothermia do to CBF?

Answer 10

decreased CBF

Question 11

hyperthermia does what to CBF?

Answer 11

increases CBF

Question 12

CBF with age:

Answer 12

CBF decreases with age

Question 13

Hypertension shifts autoregulation curve which direction? what happens to CBF?

Answer 13

• rightward shift

- increases CBF

Question 14

High ICP. What is one of the first things we can do to help reduce it?

Answer 14

hyperventilate

Question 15

CO2 combines w/ H2O to form carbonic acid, which forms H-

o The H-’s are what cause

Answer 15

the vasodilation of cerebral vessels (causing an increase in CBF)

Question 16

Studies show electrical stimulation of excitatory glutaminergic neurons leads to increase in

Answer 16

intracellular calcium ion and vasodilation of nearby arterioles

Question 17

The cerebral blood flow is maintained fairly stable for a MABP of

Answer 17

50-150/60-160.

Question 18

Beyond MABP of 150 you will get an increase in cerebral blood flow and will be at risk in developing

Answer 18

hemorrhage…. < 50= hypoperfusion

Question 19

Autoregulation of CBF is responsive to what two mechanisms?

Answer 19

o mean blood pressure changes

o pulsatile pressure (perfusion pressure– for example…decreased during Cardio Pulmonary Bypass)

Question 20

• People with hypoperfusion/ cerebral ischemia, autoregulation is shifted

Answer 20

to the left

Question 21

• People with chronic HTN, autoregulation is shifted to the

Answer 21

right

Question 22

• Brain uses what at a near constant rate?

Answer 22

O2

Question 23

Cerebral circulatory system has strong sympathetic innervation that passes upward from the superior cervical sympathetic ganglia and then into

Answer 23

the brain

Question 24

transection of SNS or mild stimulation of SNS usually causes little change in CBF because the blood flow autoregulation overrides the

Answer 24

nervous effects

Question 25

When MAP rises acutely during strenuous exercise, SNS constricts the large and intermediate-sized brain arteries enough to prevent the high pressure from reaching the smaller brain blood vessels. Thus, preventing

Answer 25

vascular hemorrhages

Question 26

what area of the brain is most sensitive for hypoxia / ischemia?

Answer 26

hippocampus (area for recent memories)