Neuraxial

Question 1

What are the steps in management of a suspected total spinal?

Answer 1

• call for help, communicate, delegate
• reassure the awake pt while working through steps
• 100% O2, gentle ventilatory support if needed
• if conscious state deteriorates, secure airway (RSI/tube)- can achieve without induction agent or w relaxant only if pt has lost consciousness
• rapidly infuse fluids, (elevate LLs- although the issue is high spinal), in pregnant ensure have L) uterine displacement (*this is recommended vs just L) lateral tilt)
• use vasopressors to maintain BP, give atropine +/- adrenaline for ass’d bradycardia
• if lose CO, start CPR, give 1mg Adr IV & go to PEA protocol
• in pregnant, aim for delivery within 4 mins if no ROSC
• transfer to ICU for ongoing ventilation & Mx until block reverses & function returns

Question 2

What are some differentials for possible high spinal?

Answer 2

vasovagal
LAST
IVC compression
air embolism
haemorrhage

Question 3

What medications give to improve output in adult high spinal?

Answer 3

atropine 0.6-1.2mg
phenylephrine 50-100microg
Ephedrine 12-15mg
Adrenaline 25-50microg

Question 4

What’s one of the reasons why spinal anaesthesia provides a more profound block than epidural?

Answer 4

spinal is more effective at inhibiting spatial summation (where stimuli from multiple areas interact at the spinal cord level, evoking pain)

Question 5

Which modality & fibres are usually blocked the first/ highest to lowest?

Answer 5

cold (C), pinprick (A delta), touch (A beta)

Question 6

What’s bromide 0-4?

Answer 6

0= no motor block
1= unable to raise extended leg but can move knees/feet
2= unable to raise extended leg & move knee but can move feet
3= complete motor block of limb

Question 7

Do vasomotor changes occur at a higher or lower level than sensory changes after neuraxial?

Answer 7

higher

Question 8

What’s density? does it vary with temperature?

Answer 8

Ratio of mass to volume, yes.

Question 9

what’s specific gravity?

Answer 9

the density of a substance to a standard, usually relating LA solutions at 20deg C to water at 4deg C.

Question 10

What’s baricity?

Answer 10

Baricity is the ratio of the density of local anaesthetic and CSF, bot at 37deg C.

Question 11

does density have a unit? how about baricity? specific gravity?

Answer 11

Yes, weight per unit volume. Baricity & specific gravity have no unit as they’re ratios.

Question 12

What’s the mean density of CSF?

Answer 12

1.0003g/L

Question 13

What’s the baricity of plain bupivacaine?

Answer 13

0.999, so it’s only 9on the edge of being hyperbaric, thus is “plain”

Question 14

How to make glucose-free solutions used intrathecally hypobaric?

Answer 14

cool to 5deg C before injection

Question 15

Is CSF denser in women or men, pregnant or non-pregnant, pre or postmenopausal?

Answer 15

LOWER CSF density in women, pregnant, pre-menopausal

Question 16

What concentration of glucose is added to “heavy” bupivacaine?

Answer 16

8%

Question 17

Above which concentration of glucose will a LA behave in a hyperbaric manner in CSF?

Answer 17

0.8%

Question 18

How does increasing the dose of LA injected for a spinal influence the spread & duration?

Answer 18

Not a dramatically different impact on spread- increasing dose by 50% within the normal ranges used only increases by a dermatome or so, however duration of block significantly increased

Question 19

Does volume of solution of injectate for a spinal influence mean spread?

Answer 19

not clinically significantly

Question 20

Is density increased or decreased with increasing temperature?

Answer 20

decreased

Question 21

What solutions are more viscous? plain or heavy? does a more viscous solution spread further?

Answer 21

heavy. Spreads further & produces more even distribution.

Question 22

What’s the blood supply to the spinal cord?

Answer 22

1x anterior & 2x posterior spinal arteries- NAP 3 thing