General and Regional Anesthesia Techniques
What to understand
General anaesthesia: the triad (hypnosis, analgesia, muscle relaxation), induction and maintenance options, airway management decision-making, and the principles of rapid sequence induction (pre-oxygenation, cricoid pressure controversy, suxamethonium or rocuronium). Regional anaesthesia: neuraxial (spinal vs epidural - onset, density, catheter use, hypotension, post-dural puncture headache), peripheral blocks (landmark vs ultrasound), and the concept of local anaesthetic systemic toxicity (LAST). Know the maximum doses of common local anaesthetics (lidocaine, bupivacaine, ropivacaine) and that adrenaline prolongs duration and reduces systemic absorption. Understand the difference between spinal and epidural mechanisms and the role of intralipid in LAST.
Traps
- Confusing spinal (single-shot, rapid, dense, CSF confirmed) with epidural (catheter, slower, segmental).
- Forgetting that bupivacaine is more cardiotoxic than lidocaine in LAST.
- Missing that a high spinal can cause hypotension and bradycardia (Bezold–Jarisch reflex) and requires airway support.
- Assuming ultrasound eliminates complications - it reduces, not abolishes, LAST and nerve injury.
Rule of thumb
For any block question, ask: what is the target, what is the maximum safe dose, and what is the rescue? Intralipid is the rescue for LAST; vasopressors and fluids are the rescue for neuraxial hypotension.
Worked example
A patient develops seizures and cardiovascular collapse after a large bupivacaine dose. This is LAST: stop injection, secure airway, give 20% lipid emulsion, and support circulation - do not give more local anaesthetic.