Neuraxial

Question 1

Vertebral column

Answer 1

7 Cervical
12 thoracic
5 lumbar
5 fused sacrum

Anterior - longitudinal ligaments
Posterior - ligamentum flavum

Question 2

End of spinal cord

Answer 2

Adults - L1

Kid - L2-3

Question 3

End of dural sac

Answer 3

Adults - S1-2

Kids - S3-4

Question 4

Blood supply to SC

Answer 4

Anterior spinal artery (2/3 of supply) from vertebral artery

Posterior spinal arteries (1/3 supply) from PICA

Question 5

Artery of Adamkiewicz

Answer 5

collateral from aorta

~T9-12 –> usually L-sided

Question 6

Site of action for local/pain control of neuraxial

Answer 6

primarily the nerve roots

Question 7

Anterior cord block effects?

Answer 7

motor and autonomic

Question 8

Posterior cord block effects?

Answer 8

somatic and visceral sensors

Question 9

Somatic blockade

Answer 9

interrupts afferent transmission

• sympathetic = 2 segments cephalad higher than sensory
• Sensory = 2 segments more cephalad than motor blockade

Question 10

CV effects of autonomic blockade

Answer 10

drop in venous return and BP - proportional to dermatomal level and sympathectomy
*both arterial and venous relaxation

Question 11

Bezold-Jarisch Reflex

Answer 11

drop in venous return –> less filling of heart –> less cardiac stretch –> increased parasympathetic tone –> bradycardia

Question 12

Pulmonary effects of blockade

Answer 12

C3-5 = phrenic (diaphragm) not really touched

- can get some accessory and intercostal muscle weakness

Question 13

GI effects of blockade

Answer 13

vagal tone predominance –> increased peristalsis

Question 14

What affects spinal anesthetic spread?

Answer 14

1. Baricity
2. Position
3. Dose
4. Site of injection
5. Height?

Question 15

Hyperbaric solution

Answer 15

heavy –> steer with gravity

Question 16

Isobaric solution

Answer 16

equal to CSF –> stays at level of injection

Question 17

Hypobaric solution

Answer 17

less than CSF –> rises against gravity

Question 18

Apex of thoracolumbar curve?

Answer 18

T4 –> limits spread of hyperbaric solution in supine position

Question 19

How does CSF volume affect spread?

Answer 19

Lower CSF volume = more spread

*Pregs, ascites, tumors

Question 20

Infant spinals

Answer 20

rapid onset, short duration due to more volume per kg and higher CO and vascular pia matter

Question 21

Epidural space surrounds what of SC?

Answer 21

dura matter posteriorly and nerve roots

Question 22

Factors affecting level of epidural block?

Answer 22

Mass = volume x [ ]
- volume matters most
opioids augment quality of block