Lecture IX

Question 1

Drugs to give with Epinephrine

Answer 1

• Lidocaine

* Mepivicaine

Question 2

Drugs for which Epinephrine is less effective

Answer 2

Highly protein bound

• Ropivicaine
• Bupivicaine

Question 3

Neuraxial Anesthesia

Answer 3

type of regional anesthesia that involves injection of anesthetic medication in the fatty tissue that surround the nerve roots as they exist the spine (also known as an epidural) or into the cerebrospinal fluid which surrounds the spinal cord (also known as a spinal).

Question 4

Neuraxial Anesthesia Absolute Contraindications

Answer 4

Infection at site of insertion, bleeding diathesis, elevated ICP, patient refusal

Question 5

Neuraxial Anesthesia Relative Contraindications

Answer 5

Bacteremia, pre-existing neurological disease, abnormal coagulation, cardiac disease

Question 6

spinal block

Answer 6

• Drug around cauda equina

* Can spread upwards

Question 7

Epidural Block

Answer 7

• Drug around nerve roots

* Sectioning areas

Question 8

Neuraxial Anesthesia Respiratory Effects

Answer 8

Loss of proprioception

Question 9

Neuraxial Anesthesia CV Effects

Answer 9

• Hypotension

* Bradycardia

Question 10

Absorption Depends on…

Answer 10

• Lipophilic drugs get sequestered in tissue
• High blood flow to an area increases the consumption
• Renal failure patients need more charged molecules due to the acidosis

Question 11

Elimination of Esters

Answer 11

Esters have one i in the name

plasma cholinesterase

Question 12

Elimination of Amides

Answer 12

Amides have two i’s in the name

Liver- hydrolyzed by cytP450

Question 13

Bupivicaine Maximum Recommended dose

Answer 13

3 mg/kg for adults

2.5 mg/kg for infants

Question 14

Lidocaine Maximum Recommended dose

Answer 14

5 mg/kg plain

7 mg/kg with epinephrine

Question 15

Neurotoxicity of Local Anesthetics

Answer 15

• Inhibition of inhibitory neurons>excitatory Neurons
• Lightheadedness, Peri-oral numbness, Seizures, Tinnitus
• Worsened by acidosis because of: If you have acidosis you will have more blood delivery to the brain and that can lead to seizures. Decreased protein binding.

Question 16

Treatment for LA induced seizures

Answer 16

• Hyperventilation to decrease blood flow to the brain
• Benzodiazepines
• Succinylcholine (decreases action potentials)

Question 17

Cardiovascular Toxicity

Answer 17

Cardiac sodium channel blockade: Bupivicaine disassociates from cardiac sodium channels more slowly than lidocaine

*Coronary vasospasms and arrhythmias

• Heart Blocks
• Tachycardia
• Fibrillation

Question 18

Treatment of LA induced CV toxicity

Answer 18

Prevent:

Use NE first to see where the needle is positioned, if in the wrong place you get tachycardia.

Treat arrhythmias:
Epi, atropine, vasopressin, amiodarone
DO NOT USE LIDOCAINE
Defibrillation

20% Intralipid
1cc/kg bolus
0.5cc/kg/min infusion
Creates a “sink” that LA can be sequestered into

Question 19

Transient Neurological Symptoms

Answer 19

Sensory disturbances of pain in back or lower extremities

• 4-40% with lidocaine
• Not concentration dependent unlike neural toxicity

Possible etiologies:
*nerve stretch

Question 20

Post Dural Puncture Headache

Answer 20

CSF can continue to leak out and the brain sags. (headache that is frontal or occipital- they get better when they lay down worse when they sit up)

Question 21

PDPH Treatment

Answer 21

Analgesics
Blood Patch
Patients own blood, into epidural space and will increase pressure
Caffeine to vasoconstrict

Question 22

Allergic Reaction

Answer 22

Mostly always esters: one i in the name

Most likely from a preservative in the medication