Local anaesthetic toxicity

patient risk factors

  • 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

clinical features

CNS effect → resp → cardiovascular

  • Perioral numbness/tingling; visual disturbance
  • confusion, slurred speech
  • lower dose =
    • sympathomimetic
    • seizures
  • higher dose =
    • vasoplegic hypotension, bradycardia, QRS prolongation
    • coma

pathogenesis

  • bupivacaine is especially cardiotoxic
    • inhibits L-type calcium channels (?and VGCCs) → disrupt Cardiac contractility
    • inhibits acylcarnitine exchange in cardiac mitochondria

management

  • Intralipid
  • Mechanism is unclear - suggested mechanisms:
  • Dosing:
    • 1.5ml/kg of 20% lipid over 1 min AND
    • 20% infusion at 15ml/kg/h

#toxicology #pharmacology

local anaesthetics
Safe local anaesthetic administration teach

https://www.mdpi.com/1422-0067/27/15/6900
https://www.bjaed.org/article/S2058-5349(17)30154-3/fulltext
DOI: 10.1177/0300060520942619 Gao et al 2020