What is the recommended dose of lox (lidocaine) 2% nebulizer (nebs) solution in milliliters (mL) for administration through a tracheostomy tube?

Lidocaine 2% Nebulization Through Tracheostomy: Dosing and Administration

Direct Answer

The maximum safe dose of lidocaine 2% for nebulization through a tracheostomy tube is 9 mg/kg lean body weight, which translates to approximately 4.5 mL per kg of the 2% solution (20 mg/mL concentration), though this maximum is rarely needed in clinical practice. 1

Critical Dosing Parameters

Maximum Dose Calculation

• Never exceed 9 mg/kg lean body weight of total lidocaine, regardless of administration route or technique 1
• For a 2% lidocaine solution (20 mg/mL), this equals 0.45 mL/kg as the absolute maximum volume 1
• This is a safety ceiling, not a target dose—most patients require significantly less 1

Practical Volume Guidelines

• Typical nebulization volumes range from 3-5 mL total when diluted appropriately 1
• For a 70 kg adult: maximum 630 mg lidocaine = 31.5 mL of 2% solution (far exceeding practical nebulization volumes) 1
• Most clinical applications use 2-4 mL of 2% lidocaine for airway topicalization via nebulization 1

Critical Safety Warnings

Enhanced Systemic Absorption Risk

• All nebulized drug enters the respiratory tract directly through the tracheostomy, bypassing first-pass metabolism 1
• This creates significantly higher systemic absorption compared to oral administration, increasing toxicity risk 1
• Toxic plasma concentrations occur with doses of 6.0-9.3 mg/kg, making the 9 mg/kg maximum a narrow safety margin 1

Toxicity Prevention

• Have lipid emulsion immediately available for local anesthetic systemic toxicity (LAST) treatment 1
• Monitor for signs of toxicity: perioral numbness, metallic taste, tinnitus, confusion, seizures, cardiac arrhythmias 1
• Account for ALL lidocaine administered from any route (regional blocks, surgical infiltration, other topical applications) toward the maximum dose 1

Administration Technique Through Tracheostomy

Device Selection

• Nebulized lidocaine has variable absorption, requiring careful dose monitoring 1
• Consider that absorption variability may necessitate higher doses to achieve adequate topicalization, but this increases toxicity risk 1

Proper Administration Steps

• Remove inner cannula before nebulization if present 2
• Ensure adequate humidification is maintained throughout the procedure 1, 2
• Test adequacy of topicalization atraumatically (e.g., with soft suction catheter) before proceeding with any airway instrumentation 1

Clinical Context and Indications

Appropriate Use

• Lidocaine nebulization through tracheostomy is primarily indicated for airway topicalization before procedures such as tube changes or bronchoscopy 1
• Do NOT use routinely to suppress cough—the cough reflex is protective against life-threatening mucus plugging in tracheostomy patients 3

Common Pitfall to Avoid

• Never use lidocaine or other medications not FDA-approved for tracheostomy nebulization without appropriate safety studies, as distribution, absorption, and toxicity profiles differ significantly from standard routes 3, 4
• Invasive topicalization techniques (glossopharyngeal/superior laryngeal nerve blocks) are associated with higher plasma concentrations and should be reserved for those with specific expertise 1

Alternative Considerations

Lower Concentrations

• Some evidence suggests lower lidocaine concentrations are equally effective as higher concentrations for topicalization 1
• Higher concentrations may provide more rapid onset but increase systemic absorption risk 1

Emergency Medication Administration

• If using the tracheostomy for emergency drug delivery (epinephrine, atropine, naloxone), dilute to 3-5 mL with 3-5 mL flush, administer through catheter beyond tube tip, and follow with bagging 1
• For emergency epinephrine specifically, IV route is strongly preferred; endotracheal doses of 0.01-0.03 mg/kg are ineffective 1