Is it safe to aerosolize lidocaine (local anesthetic)?

Safety of Aerosolized Lidocaine

Aerosolized lidocaine should be used with caution due to potential risks of local anesthetic toxicity, bronchospasm, and anaphylactic reactions, particularly in patients with cardiac disease, electrolyte disorders, seizure disorders, or respiratory conditions. 1

Safety Considerations

Potential Risks

• Systemic Absorption: While aerosolized lidocaine typically results in minimal systemic absorption with undetectable or low serum levels (<0.05 μg/ml) when used alone 2, there are important safety considerations:

• Toxicity Risk Factors:

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

• Airway Complications:

  • Bronchospasm, particularly in patients with reactive airways
  • Anaphylactic reactions (rare but potentially life-threatening) 3
  • Initial bronchoconstriction with higher concentrations 4

Dosing Considerations

When aerosolized lidocaine is deemed necessary, follow these guidelines:

• Concentration: 4% solution (2.0 mg/kg) provides optimal balance between efficacy and safety 4

  • Lower concentrations (1%) may be insufficient for adequate anesthesia
  • Higher concentrations (10%) increase risk of bronchospasm without additional benefit

• Maximum Dose: Should not exceed 120 mg/hour 1

• Weight Restrictions: Should not be used in patients weighing <40 kg 1

• Calculation Method: Use ideal body weight for dose calculation:

  • Men: height (cm) - 100
  • Women: height (cm) - 105 1

Clinical Applications and Precautions

Procedural Use

Aerosolized lidocaine can be beneficial for:

• Bronchoscopy (reduces total dose of topical anesthetic needed) 5
• Laryngoscopy and intubation (prevents hypertension and tachycardia) 6

Safety Protocols

• Monitoring: Continuous ECG, pulse oximetry, and regular blood pressure monitoring during administration 1
• Emergency Preparedness: Equipment for managing local anesthetic toxicity should be immediately available
• Timing: Avoid concurrent use with other local anesthetics:
  • No nerve blocks within 4 hours before or after lidocaine aerosol
  • Remove topical lidocaine plasters before administration 1

Special Considerations for COVID-19

• Aerosolization procedures should be considered aerosol-generating procedures (AGPs) requiring appropriate PPE:
  • Gown + gloves + powered air-purifying respirator or N95 mask + goggles or face shield 1
• Limit personnel exposure during aerosol-generating procedures 1

Conclusion

While aerosolized lidocaine can be used safely in most patients, careful patient selection and appropriate dosing are critical. The 4% concentration (2.0 mg/kg) appears to provide the optimal balance between efficacy and safety 4. Always monitor for signs of local anesthetic toxicity, which can range from mild symptoms (tingling of tongue/lips, light-headedness) to severe complications (seizures, cardiac arrhythmias, and even cardiac arrest) 1.