What is the recommended protocol for administering a lidocaine (local anesthetic) injection?

Protocol for Administering Lidocaine Injections

The recommended protocol for lidocaine injection includes using ideal body weight for dose calculation, not exceeding 1.5 mg/kg for loading doses given over 10 minutes, and maintaining proper monitoring throughout administration. 1

Dosing Guidelines

• Calculate dosage using ideal body weight (IBW), which can be determined by:

  • Men: IBW = height in cm - 100
  • Women: IBW = height in cm - 105 1

• Do not use lidocaine in patients weighing less than 40 kg 1

• Maximum recommended dosing parameters:

  • Loading dose: No more than 1.5 mg/kg given as an infusion over 10 minutes 1, 2
  • Maintenance infusion: No more than 1.5 mg/kg/hour 1, 2
  • Maximum hourly dose: 120 mg/hour regardless of weight 1

Administration Technique

• Use a suitable infusion device that is:

  • Dedicated and properly labeled
  • Lockable and tamper-proof
  • Adjustable for fixed rate and upper rate limits 1, 3

• Deliver through a separate, dedicated cannula with:

  • Minimum flow of 0.9% sodium chloride at 10 ml/hour
  • One-way valve to prevent retrograde flow
  • Proper labeling of the infusion line 1

• Initial infusion should be:

  • Administered with an anesthesia provider present
  • Monitored with continuous ECG and pulse oximetry
  • Checked with regular blood pressure measurements (every 5 minutes during initial infusion and first 15 minutes thereafter) 1, 2

Safety Considerations

• Avoid concurrent use with other local anesthetics:

  • Do not start lidocaine within 4 hours of any nerve or fascial plane block
  • Do not perform nerve blocks until 4 hours after completing lidocaine infusion
  • Remove topical lidocaine plasters before starting infusion 1, 4

• Be vigilant for signs of local anesthetic toxicity:

  • Early signs: tingling of tongue/lips, light-headedness, tinnitus, slurred speech
  • Progressive signs: muscle twitching, loss of consciousness, respiratory arrest
  • Severe toxicity: myocardial depression, cardiac arrhythmias, ventricular arrest 1

• Relative contraindications include:

  • Cardiac disease
  • Electrolyte disorders
  • Seizure disorders
  • Renal or hepatic impairment
  • Pregnancy/breastfeeding
  • Neurological disorders 1

Special Considerations

• Single-shot spinal blockade can be used concurrently with lidocaine due to the small dose of local anesthetic used 1

• For subcutaneous infiltration, consider diluting lidocaine with normal saline in a 1:10 ratio to reduce pain during injection 5

• For tumescent lidocaine anesthesia (large volume, dilute concentration), maximum safe dosages are estimated at:

  • 28 mg/kg without liposuction
  • 45 mg/kg with liposuction 3

• Optimal anesthetic effect for topical 4% lidocaine gel occurs between 35-40 minutes after application 6

• When performing peripheral nerve blocks, smaller volumes with higher concentrations may provide more effective and longer-lasting blocks than larger volumes with lower concentrations containing the same total dose 7