- extremes of age
- acidosis
- pregnancy (!)
- hyperkalaemia
drug/clinician risk factors
- bupivacaine is reported more cardiotoxic
- blocks in head/neck, or in well vascularised sites with rapid absorption
- large volume blocks
CNS effect → resp → cardiovascular
- Perioral numbness/tingling; visual disturbance
- confusion, slurred speech
- seizures
- lower dose = sympathomimetic
- higher dose = vasoplegic hypotension, bradycardia, QRS prolongation
- ↓ availability of circulating LA - lipid infusion (changes distribution)