Propofol

Question 1

Mechanism of action

Answer 1

Selective modulator of GABAa receptors

Increases transmembrane chloride conductance

Question 2

Elimination half time

Answer 2

0.5-1.5hrs

Question 3

Clearance

Answer 3

30-60mLs/kg/min

Question 4

Metabolism

Answer 4

Hepatic metabolism
Glucuronide & Sulphate conjugates
Inactive metabolites
Excreted in the urine

Question 5

Dose for induction
Anaesthesia maintenance dose
Sedation dose

Answer 5

2mg/kg in adults, 3mg/kg in children
100-300mcg/kg/min
25-100mcg/kg/min

Question 6

Cardiovascular effects

Answer 6

Dec systemic BP
Dec cardiac output
Dec SVR
Effects exaggerated in hypovolaemia, elderly, compromised LVF
Bradycardia and asystole are rare, but reported

Question 7

Respiratory effects

Answer 7

Dose dependent ventilatory depression
Apnoea in 25-35% of pts
Bronchodilation

Question 8

CNS effects

Answer 8

Dec cerebral blood flow
Dec cerebral metabolic rate
Dec ICP
No effect on auto regulation
EEG burst suppression in high doses

Question 9

Describe Propofol infusion syndrome

Answer 9

Pts receiving high doses of Propofol can develop a lactic acidosis followed by rhabdomyolysis, then impaired oxidation of long chain fatty acids and a uncoupling of electron transport in oxidative phosphorylation

Question 10

Describe the Propofol preparation

Answer 10

20mL Lipid emulsion preparation containing Propofol 200mg, soya bean oil 2000mg, glycerol 450mg, egg lecithin 240mg, sodium oleate 6mg, sodium hydroxide

50mL preparation as per 20mL with adjusted dose

Question 11

Volume of distribution

Answer 11

3.5-4.5l/kg