Anaesthesia

Question 1

Describe the pharmacokinetics of propofol.

Answer 1

Distribution half-life 2-4 minutes
Elimination half-life 4-23 minutes
Duration of action 3-8 minutes
Rapid onset and recovery due to redistribution

Question 2

What dose of propofol is used for sedation? And for general anaesthesia?

Answer 2

Sedation: 0.5-1.0 mg/kg
Induction: 1.0-2.5 mg/kg in adults

Question 3

What clinical effects should be anticipated when using propofol?

Answer 3

Apnoea (jaw thrust, chin lift)
Hypotension
No analgesia
Antiemetic properties
Sedation
Resp depression (use end-tidal CO2 monitor)
Allergy (soy, eggs)
Pain at injection site

Question 4

How can you limit the adverse effects when using propofol?

Answer 4

Reduce dose
Use aliquots rather than a full bolus
Titrate slowly
No opiates / benzodiazepines administered simultaneously

Question 5

What is the mechanism of action of bupivacaine?

Answer 5

Blocks sodium channels, reducing propagation of nerve impulses.

Question 6

How long will a bupivacaine block last?

Answer 6

3-6 hours.

Question 7

What are the potential adverse effects from bupivacaine?

Answer 7

CVS - arrhythmia, cardiac arrest

CNS - transient neurological sequelae such as visual and auditory disturbance, seizures