IV Anesthetics Quick Reference

Question 1

Propofol

Answer 1

Induction adults 1.5-2.5 mg/kg
TIVA maintenance adults 100-300 mcg/kg/min
Conscious sedation 25-100 mcg/kg/min
Antiemetic/pruritic- 10mg

Modulator of GABAa receptors/potentiates GABA

Chloride conductance into cell hyperpolarizes (inhibitory effect)

Hepatic metabolism-rapid and extensive
Extrahepatic uptake by lungs
Elimination halftime 0.5-1.5 hrs

EDTA vs metabisulfate

Egg yolk NOT egg white which people are allergic to

Question 2

Etomidate

Answer 2

Induction 0.2-0.4 mg/kg

GABAa modulation (highest affinity)

Use in cardiovascular instability

Elimination half-time 2-5 hrs-rapid in liver

-myoclonus
-inhibits 11 B-hydroxylase- cortisol production
-PONV
-AIP- induces ALA-synthetase which leads to a unbuild up of heme precursors

Question 3

Ketamine

Answer 3

Induction 2-2.5 mg/kg 3-5min onset
IM 4-6 mg/kg 5-15 min
PO 10 mg/kg high first pass
Chronic pain 5-120 mcg/kg/min infusion

NMDA receptor antagonist (block excitatory pathway) keeps glutamate from displacing Mg in the Na/Ca channel

Elimination half-life 2-3 Hepatic with active metabolite norketamine- 1/3 potency

Bronchodilation B-2 agonist -airway reflexes preserved
Salivation
Opioid receptors (kappa and mu)
CBF/CMRO2/ICP increased- can be compensated for with hyperventilation
Nystagmus and increased IOP

Question 4

Barbiturates (methohexital)

Answer 4

GABAa modulation
Methohexital- lowers seizure threshold, ECT
CNS depressants
Suppress spontaneous ventilation

Contraindicated in AIP

Question 5

Benzodiazepines

Answer 5

Act on subset of GABAa receptors-enhances effect of GABA but has a ceiling effect

Primarily used for anxiolytics and anterograde amnesia (not memories AFTER administration)

Classified according to half-life
Diazepam
Lorazepam
Midazolam (<6 hrs) active metabolite 1-hydroxymidazolam

10 minute onset-avoid dose stacking

Question 6

Flumazenil

Answer 6

Benzo reversal
0.2 mg- do not exceed 1mg
Half-life < 1hr =watch for re-sedation
Possibility of inducing seizures in chronic benzo use

Question 7

Dexmedetomidine

Answer 7

0.5-1 mcg/kg loading-10-20 min
0.2-0.7 mcg/kg/hr infusion

Alpha-2 agonist- (GPCR) inhibits Ca channels and activates potassium-hyperpolarizing cell and causing reduced NE outflow (-) feedback

Elimination half-life 2 hours
VARIABLE context sensitive half-life

No resp depression-airway reflexes intact
Lowers MAC
Mimics natural sleep
Antishivering/blunted response to surgical stress
Analgesic effects
Antisialagogue