IV anesthetics

Question 1

Propofol

Answer 1

Dose = 1-2 mg/kg
Onset = 15-45 sec
Duration = binds brain in 2 min and then steadily wears off in 10 min
Widely used, some cv depression, NO NAUSEA
stimulates vagaries outflow –> saluvation and bronchoconstriction

Question 2

Etomidate

Answer 2

Dose = .2-.3 mg/kg
Onset = 15-45 sec
Duration = very quick (3-5 min)
Favored for hero instability because of minimal cv depression
Pai with injection, involuntary movements, lots of nausea
Adrenal suppression by inhibiting hydroxyl are (4-8 hrs)

Question 3

Thiopental

Answer 3

Dose = 3-5 mg/kg
Onset = 15-30 sec
Duration = 5-10 min
Barbituate with favorable Neuro profile, long half-life
Increases pain sensitivity
Decreases SVR and contractility –> hypotension and reflex tachy

Question 4

General MOA

Answer 4

Augment post synaptic GABA –> increase Cl influx –> hyper polarize cell –> decreased excitability of neurons

Question 5

Dosing considerations

Answer 5

Adjust for diseases with protein deficiency

• CHF
• malignancy
• renal and hepatic failure

Question 6

Methohexital

Answer 6

Dose = 1-2 mg/kg
Onset = 15-30 sec
Duration = 5-10 min
Barb used in ECT and cath lab procedures, has more rapid clearance and half-life than thiopental
Decreases seizure foci threshold, good for Neuro cases to ID those spots
Involuntary movements

Question 7

Ketamine

Answer 7

Dose = 1-2 mg/kg IV, 4-6 mg/kg IM
Onset = 30-60 sec IV, 3-4 min IM
Duration = 5-10 min IV, 12-25 min IM
Phenylcyclidine derivative, NMDA receptor
Analgesia and dissociative hypnosis
Causes increased sympathetic outflow causing increased HR and BP, increased CBF and ICP
Hallucinations but can be pretreated by benzos

Question 8

Dexmedetomidine

Answer 8

Dose = 0.5-1 mcg/kg (give loading dose over 10 min)
Selective alpha2 agonist -> sedative, amnestied, analgesic
Minimal respiratory depression
Causes dose-dependent hypotension and bradycardia

Question 9

Benzodiazepines

Answer 9

MOA = increases membrane permeability to Cl -> hyperpolarization
Anxiolytics and amnestic –> not good for induction
Respiratory depression -> can reverse with flumazenil
Large doses can cause decreased preload and afterload

Question 10

Midazolam

Answer 10

Versed
Dose = 1-2 mg/kg IV, 0.25 mg/kg PO
Onset = 1-3 min IV, 15-30 min PO

Question 11

Lorazepam

Answer 11

Ativan
Dose = 1-4 mg IV and PO
Onset = 1-5 IV, 30-60 PO

Question 12

Diazepam

Answer 12

Valium
Dose = 2-10 mg IV and PO
Onset = 1-5 IV, 20-40 PO