IV Anesthetics

Question 1

Overview

Answer 1

• Rapid Induction (1 arm brain time)

- then maintained with inhalational anesthetic

Question 2

Induction

Answer 2

• % binds to plasma proteins (some remain unbond) –> drug carried by veins to heart and then to brain)
• due to high blood perfusion –> Large % of initial bolus is delivered to cerebral circulatio

Question 3

Rate of Transfer depends on

Answer 3

1) Arterial Concentration of Drug
2) Lipid Solubility
3) Degree of Ionization (non-ionized better)

Question 4

Drugs for IV

Answer 4

1) Barbituates (Thiopental/Methohexital)
2) BZD (Midazolam/Lorazepam/Diazepam)
3) Opiods (Fetanyl/Alfetanil/Remifetanil)
4) A2 AG (Clonidine)
5) Propofol
6) Etomidate
7) Ketamine

Question 5

Barbs

• AXN
• PK
• INDIC
• SIDE

Answer 5

AXN: - GABAa –> increase time of opening

PK: -lipid soluble –> rapid induction/short duration (redistributed in skel + adipose -> long half life)
- not v. analagesic

INDIC: - v short acting (induction)

SIDE: - apnea/cough/resp spasm

NO ANTIDOTE

Question 6

BZD

Answer 6

AXN: GABA a

MIDAZOLAM/LORAZEPAM: (onset + recovery is slow
USE: - Induction / Short term intervention (colonoscopy/dental surg)
EXTRA: -Not complete anesthesia/ retrograde amnesia

*minimal cv depression/ Resp Depression

DIAZEPAM:
-long acting
USE: -Premed (anxiety)

ANtidotes

Question 7

Opiods

Answer 7

• analgesia (can’t cause unconsciousness)
• choice –> based on duration (Fetanyl –> longest)

ATG: Naloxone

Question 8

Propofol

• AXN
• PK
• INDIC
• ADV/DISADV

Answer 8

AXN: Gaba-A -R

Pk: Low water solubility (1%-os water emulsion)

INDIC: -IV–> induction/maintaince

ADV:

• fast onset + recovery
• fast metabolism in liver –> inactive metabolite
• Antimemetic

Disadv:

• Resp Depress/Brain circ/Vasodil/ Dec Contraction
• Propofol infusion syndrome (Incr blood glucose)

Question 9

ETOMIDATE

Answer 9

• induction (rapid onset/short duration)
• 0 analgesia

ADV:
- cv stability

DISADV:

• nausea/vomit
• myoclonic movement
• supp of adrenocortical stress response

Question 10

KETAMINE

Answer 10

AXN: - NMDA ATG (bind to PCP)

• Dissociative anesthesia (use with BZD)
• Mod rapid onset/recovery

ADV:

• circ stimulation
• no resp depression

DISADV:

• hallucination
• no muscle relax

CONTRA:
-hypertony/epilepsy/eclampsia