What is the appropriate induction agent sequence and technique for awake intubation using video laryngoscopy (VL) in a patient with a large submandibular gland?

Awake Intubation Using Video Laryngoscopy in a Patient with Large Submandibular Gland

For a patient with a large submandibular gland requiring awake intubation with video laryngoscopy, use the sTOP framework: minimal sedation (1-2 mg midazolam IV titrated slowly), comprehensive airway topicalization with lidocaine, high-flow nasal oxygen at 50-60 L/min, and perform intubation with a videolaryngoscope on the first attempt after confirming adequate preparation. 1, 2, 3

Pre-Procedure Preparation

Patient Assessment and Equipment Setup

• Identify and mark the cricothyroid membrane before starting as part of a "double set-up" approach, with emergency front-of-neck airway equipment immediately available 1, 3
• Position the patient with head elevation to optimize laryngeal view and maintain airway patency 2
• Ensure the most experienced operator available performs the procedure 1

Antisialagogue Administration

• Administer glycopyrronium bromide 0.2-0.4 mg IM or 0.1-0.2 mg IV approximately 30-60 minutes before the procedure to reduce secretions that impair visualization 3

Oxygenation Strategy

Use high-flow nasal oxygen (HFNO) at 50-60 L/min as the primary oxygenation technique, as this reduces desaturation incidence to 0-1.5% compared to 12-16% with low-flow oxygen 3, 4

• Continue HFNO throughout the entire procedure to maintain oxygenation during airway manipulation 1, 3

Sedation Protocol

Minimal Sedation Approach

Administer minimal sedation only—the patient must remain responsive to verbal commands throughout the procedure 1, 3

For patients under 55 years without significant comorbidities:

• Start with 1 mg midazolam IV given over at least 2 minutes 5
• Wait an additional 2 minutes to fully evaluate the sedative effect 5
• If further sedation is necessary, give additional 1 mg increments over 2 minutes, waiting 2 minutes after each increment 5
• Total dose should not exceed 5 mg 5

For patients over 55 years or with debilitation:

• Start with no more than 1 mg midazolam given over at least 2 minutes 5
• Maximum initial dose should not exceed 1.5 mg over 2 minutes 5
• If additional titration is necessary, give no more than 1 mg over 2 minutes 5
• Total doses greater than 3.5 mg are not usually necessary 5
• These patients require at least 50% less midazolam than younger patients 5

Optional Adjunct Sedation

• Consider target-controlled infusion of remifentanil with effect site concentration of 2 ng/mL according to Minto's pharmacokinetic model if additional comfort is needed 6, 4
• Maintain spontaneous ventilation throughout—never compromise airway reflexes 1, 6

Airway Topicalization Sequence

Critical Principle

Adequate topical anesthesia is essential for success—never proceed without testing adequacy of topicalization 3

Topicalization Protocol

1. Apply 10% lidocaine spray to the oropharynx and base of tongue 4
2. Perform trans-cricothyroid block with 8 mL of 1% lidocaine injected into the tracheal lumen to anesthetize the trachea and vocal cords 6
3. Spray the entire oral cavity with 1% or 4% lidocaine 6, 4
4. Allow adequate time (several minutes) for topical anesthesia to take effect before proceeding 3

Topicalization Considerations

• Topical lidocaine has a dose-dependent duration of 40 minutes, though return of laryngeal reflexes may take longer 1
• Patients must remain nil by mouth for at least 2 hours following airway topicalization due to lidocaine's terminal elimination half-life of up to 2 hours 1

Video Laryngoscopy Technique

Device Selection for Submandibular Mass

Choose a videolaryngoscope with which you are most familiar and trained 2

• For a large submandibular gland, a channeled videolaryngoscope (such as King Vision®) is preferred as it provides a guided pathway for the endotracheal tube and has demonstrated 92% success rates in patients with periglottic masses 4
• Hyperangulated videolaryngoscopes are particularly effective for known difficult airways (success rate improvement RR 0.29) 7

Intubation Sequence

1. Insert the videolaryngoscope to visualize the glottis while maintaining patient comfort 8, 6
2. Use a stylet or bougie shaped to match the blade curvature (60° curve for hyperangulated blades) to facilitate tube passage 2, 8
3. Adopt a "patient-screen-patient" approach—do not become fixated on the screen; observe tube passage as it enters the oral cavity 1
4. Pass an armored or standard endotracheal tube with guide wire inside over the stylet/bougie 6
5. Limit attempts to a maximum of 3 by the primary operator, plus 1 attempt by a more experienced operator (3+1 rule) 1, 2

Expected Timeline

• Median time to obtain glottic view: 19 seconds (range 10-30 seconds) 4
• Median time to complete intubation: 49 seconds (range 33-107 seconds) 4

Two-Point Confirmation Check

Before inducing general anesthesia, perform mandatory two-point confirmation 3:

1. Visual confirmation: Direct visualization of the tracheal tube passing through the vocal cords with the videolaryngoscope 3
2. Capnography: Confirm presence of end-tidal CO₂ waveform to exclude esophageal intubation (sensitivity and specificity 100% in spontaneously breathing patients) 3

Management of Complications During the Procedure

If Inadequate Topicalization

• Stop the procedure immediately 1
• Apply additional topical anesthesia and wait adequate time for effect 3
• Consider postponing if patient cannot tolerate despite adequate preparation 1, 4

If Bleeding Occurs

• Videolaryngoscopy is preferred over flexible bronchoscopy when blood or secretions are present 3
• Slight bleeding does not prevent optical intubation with videolaryngoscopy 6
• Traces of blood occur in approximately 16% of cases but rarely prevent success 4

If Unsuccessful After 3+1 Attempts

Call for help immediately and ensure 100% oxygen is applied 1

• Stop and reverse any sedative drugs 1
• Default action is to postpone the procedure unless airway management is essential 1
• If essential, the preferred rescue option is awake front-of-neck airway (cricothyroidotomy or tracheostomy) performed by the most skilled clinician available 1
• If front-of-neck airway is inappropriate or unsuccessful, proceed with IV induction using full neuromuscular blockade, with videolaryngoscope as first-line device 1

Induction of General Anesthesia After Successful Intubation

Only induce general anesthesia after confirming successful tracheal intubation with both visual confirmation and capnography 3, 8, 6

Induction Agent Sequence (Post-Intubation)

Since the airway is already secured, standard induction can proceed:

• Administer IV induction agent (propofol or etomidate based on hemodynamic status) 1
• Provide full neuromuscular blockade 1
• Transition to maintenance anesthesia as planned for the surgical procedure 1

Critical Pitfalls to Avoid

• Never over-sedate—awake techniques may precipitate complete airway obstruction from over-sedation, topical anesthesia, laryngospasm, or bleeding 1, 3
• Never proceed without adequate topicalization testing—inadequate anesthesia is the primary cause of failed awake intubation 3, 4
• Never attempt multiple passes without optimization—switch techniques after 1-2 failed attempts rather than persisting 2
• Never induce general anesthesia before confirming tracheal placement—this eliminates the safety advantage of awake intubation 3
• Do not use videolaryngoscopy if mouth opening is inadequate or cervical spine is fixed in flexion—flexible bronchoscopy is preferred in these scenarios 2, 3

Post-Intubation Management

Patients who undergo awake tracheal intubation for predicted difficult airway are at high risk of complications at extubation and require an appropriate extubation strategy 1

• Plan extubation following Difficult Airway Society guidelines 1
• Consider performing laryngoscopy before extubation to assess the airway, though this may not reliably predict ease of subsequent intubation 1