Lecture 6 - Clinical Uses of anesthetics

Question 1

what are some desired components of General anesthesia?

Answer 1

• Desired components – amnesia, (Preemptive) analgesia, anxiolysis/sedation, suppressed stress and hormonal responses, immobility/muscle relaxation, autonomic areflexia

Question 2

what are the phases of anesthesia –

Answer 2

(pre induction), induction, maintence, emergence

Question 3

What are the three most commonly used IV anesthetics?

Answer 3

Propofol
Ketamine
Etomidate

Question 4

Propofol –
Mechanism
Pros vs Cons

Answer 4

Mechanism – potentiation of GABA mediated inhibition

Pros – Rapid onset/short acting; anti-emetic, bronchodilation
Cons – pain on injection; no analgesia, hypotension

Question 5

Ketamine
Mechanism
Pros vs Cons

Answer 5

Mechanism: NMDA receptor antagonists, and some opioid receptor function

Pros – dissociative states, bronchodilation, POTENT ANALGESIC,

COns – Hypertension, Increased ICP, use with caution CAD/CVA patients, tachycardia. PSYCHOTROPIC SIDE EFFECTS

Question 6

Etomidate
Mechanism
Pros vs cons

Answer 6

potentiates GABA mediated inhibition

Pros – Cardiovascularly stable (no effect on the heart of CV). Great for CV unstable patients

Cons – adrenal suppression, pain on injection, myoclonus

Question 7

Opiods – pros vs cons

Answer 7

Pros – Analgesia
§ Minimal cardiac depression; reduces inhalational agents; versatile (IV, IM, SL, regional anesthesia)

○ Cons – Respiratory depression
bradycardia, skeletal muscle rigidity, nausea and vomiting

Question 8

Of the opioids which have the shortest time of onset?

Answer 8

Remifentanil > alfentanil < Fentayl< Morphine/Meperidine/< Methadone – minutes

Question 9

How is immobility achieved during surgery?

what are the two classes

Answer 9

Depolarizing and Non Depolarizing Muscle relaxants

Question 10

Depolarizing immobility agent
Mechanism
pros
cons

Answer 10

Succinylcholine –
Mechanism – nicotinic ACH R Agonist; persistent depoarlization of the end plate

Pros – fast onset, short duration

Cons – Hyperkalemia, Trigger of Malignant Hyperthermia, Increased ICP/IOP
will be prolonged in persons who have acetylcholinesterase mutations

Question 11

Non Depolarizing immobility agents
Mechanism
Pros
cons

Answer 11

Rocuronium, Vecuronium, Pancuronium, Cisatracurium

Mechanism – competitive antagonists of the Nicotinic ACH R

Pros – fast Onset, Longer Duration

Question 12

Immobility agents –
which has the fastest onset ?

duration shortest to longest ?

Answer 12

Fastest onset – Sux (1-1.5 minutes)

Duration
Sux < Roc < Vec = Cis < Pancuronium

Question 13

Pre- induction – what medication clsas is commonly used for anti-anxiety/amnesia prior to general anesthesia?

Answer 13

Versed (midazolam) – and other benzos

Question 14

what are the common inhalational induction agents?

which is the most commonly used? why?

Answer 14

Liquid: Isoflurane, Sevoflurane, Desflurane, (Halothane)

Gaseous form: Nitrous oxide

Isoflurane – most commonly used – cheap and long lasting

Question 15

why must N2O be combined with other medications?

when is N2O contra-indicated ?

Answer 15

Combined with other meds bc its can’t reach MAC of 1 on its own

Contraindicated in surgeries with open air pockets such as laproscopic surgeries, bowel obstruction surgeries, pneumothroax, middle ear surgeries.

Question 16

which inhaled agent is good for kids before proceeding with another inducing agent ? why?

Answer 16

§ Sevoflurane: not reactive for airways; best for kids

Then switch to Isoflurane after airway secured

Question 17

patients with heart disease

• • which Inhaled anesthetic is known to cause tachycardia?
• • which IV inducing agent is known to cause tachy?
• –which IV inducing agent is best for cardiovascularly unstable patients
• –which opiate is best for patients with CV instability?

Answer 17

Inhaled tachy – desflurane

IV tachy – ketamine

CV unstable patients – Etomidate and Fentanyl

Question 18

which immobility agent is best for persons with poor kidney function?

Answer 18

Cis astricurium