Exam 1 Spinal & Epidural Neuraxial Anesthesia [6/03/24]

Question 1

What is the preservative found in Amide LA’s?

Answer 1

Methylparaben

Question 2

True or False:
If someone has an ester allergy, they will most likely have an amide allergy?

Answer 2

False
There is no cross-sensitivity between esters and amides.

Question 3

What two components of a LA determine its onset of action?

Answer 3

1. pKa
2. Concentration

Question 4

What component of a LA determines its potency?

Answer 4

Lipid solubility

Question 5

The protein binding % of a LA determines its ___.

Answer 5

Duration of Action

Question 6

Factors Influencing Vascular Uptake and Plasma Concentration of Local Anesthetics include:

STAMP

Answer 6

Site of Injection
Tissue Blood Flow
Addition of Vasoconstrictor
Metabolism
Physiochemical Properties

Question 7

Which LA do we NOT want to use in a Bier Block?

Answer 7

Bupivicaine

Question 8

Which type of LA baracity is good for Hip Replacements per Dr. Tubog?

Answer 8

Isobaric

Question 9

List examples of Hyperbaric LA solutions:

Answer 9

Bupivicaine 0.75% in 8.25% Dextrose
Lidocaine 5% in 7.5% Dextrose
Tetracaine 0.5% in 5% Dextrose
Procaine 10% in water

Question 10

What is the baracity of Bupivicaine 0.3% in water?

Answer 10

Hypobaric

Question 11

The 4 isobaric solutions listed in class are all mixed with what additive?

Answer 11

Saline

Question 12

What is the only LA mixture (per the powerpoint slides) that is combined with water but is not a hypobaric solution?

Answer 12

Procaine 10% in water = Hyperbaric

Question 13

High and Low (Peak and Trough) dermatome points in a SAB?

Answer 13

High: C3 and L3
Low: T6 and S2

Question 14

SAB Dosing Table

Answer 14

Question 15

In an epidural, while ensuring incremental dosing of 5 mls, we should be avoiding these 3 negative outcomes.

Answer 15

1. Accidental “High Spinal”
2. Hypotension from Rapid autonomic blockade
3. LAST

Question 16

Most common concentration of 2-Chloroprocaine for surgical anesthesia?
Why is this important?

Answer 16

3%

Higher concentration = faster onset

Question 17

Adding NaHCO3 increases these 4 things:

Answer 17

1. pH of LA
2. Concentration of Non-ionized form
3. Rate of diffusion
4. Speed of the onset of the block

Alkalinization

Question 18

The ___ of the LA is crucial for determining how high the anesthetic block reaches.

Answer 18

Volume

Question 19

What is the initial dose of an epidural?
What about the top-up dose?

Answer 19

Initial: 1-2 ml/segment
Top-Up: 50-75% of initial dose

Question 20

What aspect of a LA determines how strong/dense the block is?

Answer 20

Concentration

Question 21

What are some positive outcomes to adding adjuncts to neuraxial anesthesia?

Answer 21

• Postoperative Analgesia
• Extends Duration
• Improves the density of the block

Question 22

Which of the following drugs has been PROVEN to be the safest adjunct for neuraxial anesthesia?

A. Neostigmine
B. Ketamine
C. Versed
D. Clonidine
E. Magnesium

Answer 22

D. Clonidine

Rationale:
All of the other drugs are still listed as “Investigative agents” and need to be further studied in order to be validated.

Question 23

True or False:
Vasopressors improve the density, duration and analgesia in neuraxial anesthesia?

Answer 23

FALSE
Vasopressors extend the duration ONLY.

Alpha-2 agonists improve the density, duration and analgesia in neuraxial anesthesia

Question 24

Neuraxial Opioids target what area?

Answer 24

Substantia Gelatinosa of the dorsal horn (Lamina 2)

Question 25

Do neuraxial opioids diffuse into the general circulation?

Answer 25

Yes: provides a more broad pain relief.

Question 26

Examples of Hydrophilic Neuraxial anesthesia opioid adjuncts:

Answer 26

Morphine Hydromorphone Meperidine

Question 27

Examples of Lipophilic Neuraxial anesthesia opiod adjuncts:

Answer 27

Fentanyl Sufentanil

Question 28

When comparing hydrophilic opioids to lipophilic opioids, describe the duration and spread:

Answer 28

Duration is longer in hydrophilic and spreads more widely in a rostral manner

Question 29

Is the onset longer or shorter in Hydrophilic opioids? What about systemic absorption?

Answer 29

Longer Less systemic absorption

Question 30

Intrathecal, Epidural, and epidural infusion doses for Sufentanil

Answer 30

* Intrathecal: 5-10 mcg * Epidural: 25-50 mcg * Infusion: 10-20 mcg/hr

Question 31

Intrathecal, Epidural, and epidural infusion doses for Fentanyl

Answer 31

* Intrathecal: 10-20 mcg * Epidural: 50-100 mcg * Infusion: 25-100 mcg/hr

Question 32

Intrathecal, Epidural, and epidural infusion doses for Hydromorphone

Answer 32

Intrathecal: N/A Epidural: 0.5-1 mg Infusion: 0.1-0.2 mg/hr

Question 33

Intrathecal, Epidural, and epidural infusion doses for Meperidine

Answer 33

Intrathecal: 10 mg Epidural: 25-50 mg Infusion: 10-60 mg/hr

Question 34

Intrathecal, Epidural, and epidural infusion doses for Morphine

Answer 34

* Intrathecal: 0.25-0.3 mg * Epidural: 2-5 mg * Infusion: 0.1-1 mg/hr

Question 35

Occurrence of pruritis after giving an opioid adjunct in neuraxial anesthesia:

Answer 35

30-100% of the time

Question 36

Prophylactic measures to try and prevent pruritis.

Answer 36

* Minimize morphine dose < 300 mcg * Zofran * Nubain

Question 37

How long does the addition of A2 agonists extend the sensory and motor blockade?

Answer 37

Approximately 1 hour

Question 38

Doses of Precedex and Clonidine as neuraxial adjuncts:

Answer 38

Precedex: 3 mcg Clonidine: 15-45 mcg

Question 39

Which of the following LA, when a vasoconstrictor is added as an adjunct, would cause the most profound increase in duration? Lidocaine Tetracaine Bupivicaine

Answer 39

Tetracaine

Question 40

What is the most worrysome risk of performing neuraxial anesthesia on a patient taking anticoagulants?

Answer 40

Epidural Hematoma

Question 41

Symptoms of an Epidural Hematoma:

Answer 41

Lower extremity weakness, numbness Lower back pain Bowel/Bladder dysfunction

Question 42

Treatment for Epidural Hematoma:

Answer 42

Surgical decompression **within 8 hrs**

Question 43

With which patient population (taking anticoagulants) is neuraxial anesthesia a big challenge?

Answer 43

Patients with Cardiac Stents

Question 44

What are the guidelines for holding ASA in High Risk, Intermediate Risk, Low Risk and central neuraxial cases?

Answer 44

High/Intermediate: Hold 4-6 days Low: No hold Central: No additional precautions

Question 45

How long should we hold NSAIDs for High risk procedures?

Answer 45

Hold for 5 half-lives

Question 46

Place these types of surgeries in either a Low, Intermediate or High cardiac risk level: Prostate Surgery Cataract Surgery Breast Surgeries Open Aortic Surgery Orthopedic Surgery Head and Neck Surgery Peripheral Vascular Surgery Endoscopic Procedures Intra-thoracic/Intra-abdominal Surgeries

Answer 46

Prostate Surgery **(Intermediate)** Cataract Surgery **(Low)** Breast Surgeries **(Low)** Open Aortic Surgery **(High)** Orthopedic Surgery **(Intermediate)** Head and Neck Surgery **(Intermediate)** Peripheral Vascular Surgery **(High)** Endoscopic Procedures **(Low)** Intra-thoracic/abdominal **(Intermediate)**

Question 47

How long should we hold Tirofiban/Eptifibatide prior to performing regional anesthesia? What about abciximab?

Answer 47

4-8 hrs 24-48 hrs

Question 48

Hold time for Plavix, Prasugrel, Ticlopidine prior to Regional Anesthesia:

Answer 48

Plavix: 5-7 days Prasugrel: 7-10 days Ticlopidine: 10 days

Question 49

Unfractionated Heparin will inhibit which factors?

Answer 49

2, 9, 10, 11, 12

Question 50

Hold times for Low, High and Therapeutic doses of UFH?

Answer 50

Low (< 5,000 U): 4-6 hrs High (5-20,000 U): 12 hrs Therapeutic (> 20,000 U): 24 hrs

Question 51

Why might we insist on a PLT level prior to central neuraxial block?

Answer 51

If the patient has been on UFH for > 4 days

Question 52

LMWH will inhibit which factor?

Answer 52

Xa

Question 53

Hold times of medications (for regional anesthesia) in patients on therapeutic or prophylactic doses of LMWH:

Answer 53

Prophylactic: 12 hrs Therapeutic: 24 hrs

Question 54

How long should Warfarin be held prior to regional anesthesia?

Answer 54

Hold for 5 days, verify a normal INR (<1.5)

Question 55

The use of which type of anticoagulants are an absolute contraindication to neuraxial anesthesia?

Answer 55

Thrombolytic Agents (t-PA, streptokinase, urokinase)

Question 56

Hold time for direct oral anticoagulants prior to regional anesthesia: (Apixiban, Xarelto, Pradaxa, etc...)

Answer 56

DC at least 72 hrs prior to procedure