Lidocaine Dosing for Head Injury Intubation
For patients with head injury requiring intubation, administer lidocaine at 1-2 mg/kg IV as a single dose 30 seconds to 5 minutes before airway instrumentation. 1
Rationale and Mechanism
Lidocaine serves as a neuroprotective agent during rapid sequence intubation (RSI) in patients with head injury by:
- Blunting the rise in intracranial pressure (ICP) associated with laryngoscopy and intubation
- Suppressing cough reflexes that can further increase ICP
- Minimizing hemodynamic responses (blood pressure surges) that may worsen secondary brain injury
Specific Dosing Algorithm
- Standard dose: 1-2 mg/kg IV 1
- Timing: Administer 30 seconds to 5 minutes before airway instrumentation 1
- Maximum dose: Do not exceed 100 mg per single dose 1
Important Considerations
- Lidocaine is considered an optional adjunct for RSI in patients with head injury/increased ICP 1
- When using other neuroprotective agents that reduce ICP (e.g., etomidate, thiopental), lidocaine may provide less additional benefit 1
- For optimal effect, administer lidocaine 3 minutes before intubation 2
- Ensure the total dose of all local anesthetics administered (regardless of route) remains below the maximum safe dose 1
Safety Considerations
- Calculate dosage based on ideal body weight rather than actual body weight in obese patients 1
- High concentrations of lidocaine may cause myocardial depression, hypotension, and seizures 1
- Lidocaine is contraindicated in complete heart block 1
- Have resuscitation equipment and lipid emulsion available in case of local anesthetic systemic toxicity 1
Special Populations
- For pediatric patients: Same dosing of 1-2 mg/kg IV applies 1
- For elderly or debilitated patients: Consider using the lower end of the dosing range (1 mg/kg) 3
- For patients <40 kg: Use caution and calculate dose carefully based on weight 1
Clinical Efficacy
Studies have demonstrated that lidocaine effectively:
- Blunts cough reflexes and prevents dysrhythmias during intubation 2
- Dose-dependently prevents intubation-induced ICP increases 4
- Maintains cerebral perfusion pressure during airway manipulation 4
The evidence supports that 1-2 mg/kg is the optimal dose range, with doses of at least 1 mg/kg required for effective cough suppression 5.