What is the protocol for lidocaine nebulizer treatment?

Nebulized Lidocaine Protocol

Nebulized lidocaine (also called lignocaine) is primarily used in palliative care to relieve intractable cough in terminal illness, though it has additional applications in bronchoscopy and investigational uses for asthma. 1

Primary Clinical Indication

Nebulized lidocaine is specifically indicated for symptom relief in palliative care, particularly for cough suppression in end-stage disease. 1 The British Thoracic Society guidelines explicitly list lignocaine as one of the drugs unavailable in hand-held inhalers that requires nebulization for delivery. 1

Standard Protocol Components

Equipment Setup

• Use a jet nebulizer with an electrical compressor operating at 6-8 L/min flow rate 1
• Connect standard tubing to the nebulizer chamber 1
• Use a mouthpiece rather than a face mask when possible to minimize facial deposition 1
• Ensure patient sits upright in a chair 1

Dosing Regimens

For intractable cough in palliative care:

• Typical doses range from 20-160 mg per treatment 2
• More commonly, 10-400 mg has been reported effective in descriptive studies 3
• No standardized dosing protocol exists due to limited controlled trials 3

For bronchoscopy (investigational use):

• 4 mL of 4% lidocaine solution (160 mg) via nebulization prior to procedure 4
• Pediatric dosing: 4-8 mg/kg of 2% nebulized lidocaine, with 8 mg/kg showing better efficacy 5

Administration Technique

• Drug volume should be 2-5 mL total 1
• If using concentrated lidocaine, dilute with 0.9% sodium chloride (never water) to reach minimum 4 mL volume 1
• Patient should breathe normally (tidal breathing), not talk during nebulization 1
• Continue treatment until approximately one minute after "spluttering" occurs 1
• Total nebulization time typically 5-10 minutes 1
• Tap the nebulizer cup toward the end of treatment to maximize drug delivery 1

Critical Safety Considerations

Initial bronchoconstriction can occur, particularly in patients with baseline bronchial hyperreactivity. 3 The first treatment should always be supervised by medical personnel. 1

Common side effects include:

• Oropharyngeal numbness 6
• Dysphonia (hoarseness) 6
• Bitter taste 6
• Transient bronchoconstriction 3

Serum lidocaine levels remain well below toxic range even at higher doses (up to 8 mg/kg in pediatrics), indicating good safety profile. 5

Equipment Maintenance

• Clean nebulizer chamber and mouthpiece after each use by disassembling and washing in warm water with detergent 1
• Rinse thoroughly and dry completely 1
• Run nebulizer empty for a few seconds before next treatment 1
• Replace disposable components (tubing, nebulizer cup, mouthpiece) every 3-4 months 1
• Service compressor annually 1

Clinical Context and Limitations

The evidence base for nebulized lidocaine remains limited, with most data from small descriptive studies rather than large randomized controlled trials. 3, 6 Study limitations include inconsistent dosing methods, small sample sizes, and variable adjunctive therapies. 3

Nebulized lidocaine should not be considered first-line therapy but rather an alternative when traditional cough suppressants (dextromethorphan, opioids, benzonatate) have failed or are not tolerated. 3, 6

For bronchoscopy applications, one randomized controlled trial found that pre-procedure nebulized lidocaine (160 mg) did not reduce supplemental lidocaine requirements or improve patient comfort compared to placebo, questioning its utility in this setting. 4