FFinalistSouthampton · 2027
All procedures
GMC #23/Therapeutic procedures taught LA Y2, suturing Y4

Use of local anaesthetics

Inject or topically apply a local anaesthetic. Understand the maximum doses of local anaesthetic agents.

Target · Perform under supervision0% ready

Do it on a patient with a supervisor observing you (GMC “direct supervision”).

Overview

Know the maximum safe doses (a classic examinable point) and how to recognise & manage LA systemic toxicity (LAST).

Key numbers

  • Lidocaine max: 3 mg/kg (absolute max ~200 mg) plain; 7 mg/kg (absolute max 500 mg) with adrenalineBNF — lidocaine
  • Concentration: lidocaine 1% = 10 mg/mL, 2% = 20 mg/mLBNF
  • LAST management: stop, ABCDE, 100% O₂, treat seizures, and IV lipid emulsion 20% (Intralipid)AAGBI / Resus Council UK

Indications

  • Infiltration anaesthesia for suturing, incision & drainage, cannulation of an awake site, minor procedures

Contraindications & cautions

  • Always ask about allergy; aspirate before injecting to avoid intravascular injection
  • Traditional teaching: avoid adrenaline-containing LA in end-arterial territories (digits, nose, ears, penis) — though modern evidence is more nuanced

Equipment

Local anaesthetic (e.g. lidocaine 1% or 2%, ± adrenaline)Syringe & needle; antiseptic

Step by step

Prepare
  1. 1Check allergies; calculate the maximum dose for the patient’s weight
  2. 2Clean the site
Infiltrate
  1. 1Insert the needle; aspirate to ensure not intravascular, then infiltrate slowly
  2. 2Warn of a stinging sensation; wait for onset, then test before proceeding

Complications

  • LA systemic toxicity (LAST): perioral tingling → tinnitus, agitation, seizures → cardiovascular collapse/arrhythmia
  • Intravascular injection, allergy (rare), infection

OSCE tips

  • Know max doses: lidocaine 3 mg/kg plain (max ~200 mg), 7 mg/kg with adrenaline (max 500 mg) (1% = 10 mg/mL).
  • Aspirate before injecting.
  • Recognise LAST and its management: stop, ABCDE, and IV lipid emulsion (Intralipid) — call for help.

Watch

Read

Local anaesthetic infiltration (TeachMeSurgery)TeachMeSurgery

Sources & credits

Authored to UK finals standard and verified against UK guidance (BNF — lidocaine · BNF · AAGBI) and Geeky Medics OSCE guides. Southampton teaching materials © University of Southampton. Always follow current local policy.