Anesthesia, NMB, and Local

Question 1

Define: blood:gas ratio

Answer 1

How much of the drug is bound to protein in the blood (inactive): how much of the drug is free molecules (active)

Question 2

Define: MAC

Answer 2

minimal alveolar anesthetic concentration (aka potency): concentration of inhaled drug as a percent of inspired air at which 50% of the population will be TKO’d

Question 3

Characteristics that will increase MAC/decrease potency

Answer 3

hyperthermia, red hair, hypernatremia, increased NTs

Question 4

Characteristics that will decrease MAC/ increase potency

Answer 4

hypothermia, old age, opioids, hyponatremia, lipid soluble, pregnancy/postpartum

Question 5

What can you do to increase uptake and distribution of an anesthetic

Answer 5

• increase partial pressure of drug in inspired air
• increase alveolar ventilation
• decrease functional residual capacity
• decrease blood solubility
• decrease CO
• 2nd gas effect

Question 6

define: second gas effect

Answer 6

give one gas to decrease lung volume, give a second less potent drug to maintain anesthesia

Question 7

examples of inhaled anesthetic

Answer 7

NO2, Halothane (fluranes)

Question 8

examples of “fluranes”

Answer 8

isoflurane, desflurane, sevoflurane

Question 9

CNS effects of inhaled anesthetics

Answer 9

dose dependent depression of EEG, sensory/motor potentials, cerebral metabolism rates; increase in cerebral blood flow > ICP

Question 10

CVS effects of inhaled anesthetics

Answer 10

decrease in systemic resistance and mean arterial pressure, redistribution of blood flow, Iso and Des increase HR

Question 11

Respiratory effects of inhaled anesthetics

Answer 11

decreased tidal volume and reflex to hypoxia; increased respiratory rate and relaxation of smooth muscle

Question 12

Neuromuscular effects of inhaled anesthetics

Answer 12

relaxed skeletal muscle, malignant hyperthermia

Question 13

Thiopental and Methohexital

• class
• mechanism
• use

Answer 13

• Barbituate
• GABA agonist, NMDA-glutamate antagonist
• hypnosis/sedation with rapid onset/short duration > induce anesthesia

Question 14

Propofol

• mechanism
• use
• side effects
• consideration

Answer 14

• GABA agonist, alpha2 antagonist
• sedation and hypnosis, antiemetic
• propofol infusion syndrome: met acidosis, heart failure, rhabdomyolysis, hyperkalemia, renal failure
• allergies to soy and egg

Question 15

Etomidate

• mechanism
• use
• side effects

Answer 15

• GABA agonist
• elderly or minimal cardiac reserve
• pain on administration, PONV, involuntary myoclonic movement, decreased cortisol

Question 16

Ketamine

• mechanism
• use
• side effects

Answer 16

• no idea, dissociative anesthesia
• cardiovascular stimulation, people who are bleeding out/hypotensive
• dilerium, hallucinogen, nightmares, nystagmus, salivation, lacrimation

Question 17

Dexmedetomide

• mechanism
• use

Answer 17

• a2 agonist, natural sleep

- morbidly obese patients

Question 18

Succinylcholine

• class
• mechanism
• side effect

Answer 18

• depolarizing NMB
• binds to ACh receptors, ACh agonist
• dysrhythmia, sludge, malignant hyperthermia, hyperkalemia

Question 19

‘Curoniums’

• class
• mechanism
• reversal

Answer 19

nondepolarizing NMB

• blocks ACh receptors
• AChE inhibitors

Question 20

what is unique about Atracurium

Answer 20

histamine release > hypotension and tachycardia

Question 21

what is unique about pancuronium

Answer 21

can’t use with renal insufficiency

Question 22

what is unique about rocuronium

Answer 22

can be reversed by sugammadex

Question 23

Reversal of NMBs

Answer 23

AChE inhibitors (edrophonium, neostigmine, pyridostigmine) and anti-muscarinics (glycopyrrolate)

Question 24

Local anesthetics

• active form
• mechanism of action

Answer 24

weak base: nonionized form travels across the membrane, ionized form is active within the cell. Blocks the binding site of the inactivated sodium channel

Question 25

Two types of local anesthetics with examples

Answer 25

esters (procaine, cocaine, benzocaine) and amides (lidocaine, bupivacaine, and mepivacaine)

Question 26

Which nerves are the most sensitive to local anesthetics

Answer 26

nerves with the smallest diameter, most myelination, and fastest firing rate: Type B > Type C > Adelta > Agamma and Abeta> A alpha

Question 27

Nerve type responsible for sharp pain

Answer 27

Adelta

Question 28

Nerve type responsible for dull pain

Answer 28

C

Question 29

What factors influence the absorption of a local anesthetic

Answer 29

most absorption in highly vascular tissue, lipid solubility, presence of alpha1 agonists

Question 30

How do you keep the local anesthetics from spreading into systemic circulation

Answer 30

administer with an alpha 1 agonist

Question 31

which anesthetic comes with it's own alpha agonist

Answer 31

cocaine: it is a norepi reuptake inhibitor, thus more norepi in nerve terminals, more alpha stimulation

Question 32

where does metabolism of local anesthetics take place

Answer 32

esters: tissue esterases amides: liver amidases

Question 33

special considerations of local anesthetic metabolism

Answer 33

esterases have high phenotypic variation, there are slow and fast metabolizers-> watch your patient amides need a properly functioning liver

Question 34

Local anesthetic, systemic toxicity

Answer 34

nervous toxicity, cardiovascular toxicity, methemoglobinemia

Question 35

LA early CNS toxicity

Answer 35

excitation: decreased inhibition, talkativeness, sensory disturbance, restless, tremor

Question 36

LA late CNS toxicity

Answer 36

depression: lethargy, hypotension, bradycardia, decreased respiratory rate, seizure

Question 37

LA cardiotoxicity

Answer 37

Bupivacaine: reduced cardiac conductivity, excitability, contractility, arrhythmia, hypotension, bradycardia

Question 38

Local toxicity for LAs

Answer 38

Neuronal injury, transient neurologic symptoms (lidocaine), allergies (esters)