Josh's Must knows Test #2

Question 1

what is segmental blocks?

epidural or spinal?

Answer 1

epidurals are segmental blocks

Question 2

why are spinals not considered segental blocks?

Answer 2

b/c they block above and below

Question 3

One of the most important aspects of performing a proper epidural is what?

Answer 3

getting it into the right spot (remember they are segmental blocks)

Question 4

Label this

Answer 4

1. Dural Sac
2. Epidural Vein
3. Interlaminar space
4. Lamina
5. Ligamentum Flavum
6. Supraspinous Ligament
7. Intraspinous Ligament
8. Spinous Process
9. Transverse Process

Question 5

Epidural physiology:

What facilitates the rapid diffusion of LA from the Epidural Space, throught the dura and into the CSF surrounding the nerve roots?

Answer 5

the dural cuffs or sleeves have arachnoid villi and granulations that reduce the THICKNESS of the dura matter thus facilitating transfer

Question 6

B/c Epidural anesthesia is ______ dependent, relatively large volumes of LA are needed to achieve a block that spans several dermatomes.

Answer 6

DIFFUSION

Question 7

With epidurals _____ affects spread, so to get more levels give more _____

Answer 7

Volume

Volume

Question 8

With Epidurals:

The #1 factor to get action of epidural at a certain site is what?

The #2 factor is How much spread or how many dermatomes this is affected by what?

Answer 8

location
Volume

Question 9

an epidural is not like a spinal in which everything distal to the level of the block is affected, an epidural is a differential block dependent on the ______ and ________?

Answer 9

volume

site of injection

Question 10

What is the spread of epidural anesthesia termed

Answer 10

Rostral spread

the distribution of an opioid within the cerebrospinal fluid during epidural administration; it is determined by fat and water solubility properties of the narcotic

Question 11

When using a thoracis approach, it is prudent to decrease your volume by about ____ to ____% to prevent cranially spread.

Answer 11

30-50%

Question 12

Epidural:

within the range typically used for surgical anesthesia, drug _______is relatively unimportant in determining block spread

Answer 12

CONCENTRATION

Question 13

Epidural

the #1 way to tell density of block is what?

Answer 13

concentration

Question 14

Epidural: Dose, Volume , Concentration

if the drug CONCENTRATION is held constant, increasing the volume of LA (thus increasing the dose) results in significantly greater Spread.

For example notice the dose increases and VOLUME increases but the concentration remains the same thus you get a greater spread without changing the concentration

give me the doses

15 ml and 20 mL of 0.25 % Lidocaine

Answer 14

15mL x 2.5 mg/mL =37.5 mg

20 mL x 2.5 mg/mL = 50 mg

Question 15

Epidural: Dose, Volume, and Concentrations

So continued from all the info we now know.

1. a small volume of a more concentrated LA will produce what in a block?
2. Now take that same DOSE and double the volume and what will happen?

Answer 15

1. Very limited but very STRONG
2. SPREAD increases but weaker block

Question 16

Epidural: Dose, Volume, and Concentration

the increase in block level is NOT in direct proportion to volume increase. Thus Doubling the VOLUME will NOT double the block spread. it is a NON-linear relationship and doubling the volume will only increase the level about ___-__ the origional # of segments

Answer 16

1/3-1/2