Regional Anesthesia and Acute Pain Management
What you must understand
Know the anatomy and dermatomes for neuraxial and peripheral blocks. For spinal and epidural anesthesia, understand level of block, hemodynamic effects (sympathectomy causing hypotension and bradycardia), and complications (post-dural puncture headache, high spinal, epidural hematoma, infection). Learn local anesthetic pharmacology: onset, duration, maximum dose, and differential cardiotoxicity. Understand LAST management (lipid emulsion). Know peripheral block techniques (interscalene, supraclavicular, femoral, adductor canal, popliteal) with their complications (phrenic nerve palsy with interscalene, pneumothorax with supraclavicular). Understand multimodal analgesia and acute pain service principles.
Traps in questions
Classic traps: assuming a spinal block cannot cause hypotension (it can, via sympathectomy); confusing epidural and spinal spaces; and forgetting that interscalene block reliably causes ipsilateral phrenic nerve palsy - avoid in severe respiratory disease. Watch for LAST presenting with CNS symptoms (tinnitus, metallic taste, seizures) before cardiovascular collapse. Questions often test that bupivacaine is more cardiotoxic and that ropivacaine/levobupivacaine are safer alternatives. Also remember epidural hematoma risk with anticoagulation and the need for timely imaging and decompression.
Rule of thumb
For LAST, stop injection, call for help, secure the airway, and give lipid emulsion early if severe. For any new back pain plus motor/sensory deficit after neuraxial block, treat as epidural hematoma until proven otherwise.
Worked example: A patient develops tinnitus and perioral numbness during a supraclavicular block. This is early LAST; stop injection, monitor, and prepare lipid emulsion.