What are the considerations and procedure for awake fiberoptic (flexible fiber-optic endoscopy) nasotracheal intubation in patients with anticipated difficult airways or significant respiratory compromise?

Awake Fiberoptic Nasotracheal Intubation

Primary Recommendation

Awake fiberoptic nasotracheal intubation should only be performed by experienced clinicians in carefully selected patients with anticipated difficult airways, using meticulous preparation including head-up positioning, minimal sedation, adequate topical anesthesia, and active pre-oxygenation with high-flow nasal oxygen, while maintaining a clear backup plan for failure. 1

Indications for Awake Intubation

Awake fiberoptic intubation is indicated when you anticipate a difficult airway AND one or more of the following apply 1:

• Difficult mask or supraglottic airway ventilation is predicted 1
• Increased aspiration risk exists 1
• Patient cannot tolerate brief apneic episodes 1
• Emergency front-of-neck access would be difficult or ineffective 1

Critical Limitations in Critically Ill Patients

The critically ill population presents unique challenges that often make awake intubation impractical 1:

• Time-critical situations requiring urgent airway control 1
• Limited patient cooperation due to altered mental status or distress 1
• Blood, secretions, or vomitus obscuring fiberoptic visualization 1
• Risk of complete airway obstruction from over-sedation, topical anesthesia, laryngospasm, or bleeding 1
• Potential for critical respiratory failure in CPAP/PEEP-dependent patients 1

Preparation Protocol

Patient Assessment and Explanation

Perform thorough pre-operative assessment and provide careful explanation of the procedure to the patient 2. Success depends heavily on adequate preparation rather than just technical skill 2.

Equipment Preparation

• Standard fiberoptic bronchoscope or shorter flexible video rhino-laryngoscope (which may offer easier one-handed manipulation and reduced tube impingement) 3
• Appropriate nasotracheal tube (consider flexometallic, nasal RAE, or microlaryngeal tubes) 1
• Emergency front-of-neck access equipment immediately available 1
• Suction readily accessible 1

Antisialagogue Administration

Administer antisialagogue premedication to reduce secretions and improve visualization 2.

Positioning

Position patient head-up (reverse Trendelenburg or sitting) to reduce aspiration risk and improve respiratory mechanics 1.

Topical Anesthesia

All methods of achieving topical anesthesia perform similarly well with high success rates 4. Options include 2:

• Modified "spray-as-you-go" technique (lidocaine applied progressively through the bronchoscope) 5
• Nebulized local anesthetic
• Direct application to nasal passages, oropharynx, and larynx

The topical anesthesia provides adequate airway analgesia while preserving airway reflexes 6.

Sedation Strategy

Sedative Choice

Dexmedetomidine offers the best safety profile compared to other sedatives, with fewer desaturation episodes than propofol or opioid-based regimens 4:

• Dexmedetomidine: Loading dose 0.5 μg/kg over 10 minutes, followed by infusion 0.25 μg/kg/h 5
• Alternative: Sufentanil 0.2 μg/kg loading dose over 10 minutes, followed by 0.1 μg/kg/h infusion (but higher risk of respiratory depression) 5
• Midazolam: 0.02 mg/kg as premedication, with additional 0.5 mg boluses every 2 minutes as needed 5

Sedation Depth

Use minimal sedation only - target Modified Observer's Assessment of Alertness/Sedation score of 2-3 (responds to mild prodding or shaking) 5. Over-sedation risks complete airway obstruction 1.

Active Pre-oxygenation

Apply high-flow nasal oxygen (HFNO) throughout the procedure to maintain oxygenation during instrumentation 1. This is superior to standard oxygen delivery methods.

Intubation Technique

Nasal Route Considerations

• The nasal route typically requires subsequent conversion to oral tube for long-term management 1
• Risk of epistaxis which can obscure visualization 1
• Use vasoconstrictor (e.g., oxymetazoline) and adequate lubrication

Procedural Approach

1. Advance fiberoptic scope through prepared nostril under direct visualization 3
2. Navigate through nasopharynx to visualize larynx 3
3. Ensure vocal cords are open and non-reactive before advancing scope or tube 1
4. Advance scope through glottis into trachea 3
5. Railroad nasotracheal tube over scope with gentle rotation if needed 1
6. Verify tracheal placement with capnography before removing scope 1

Attempt Limits

Limit to maximum 3 attempts plus 1 additional attempt by most experienced operator 1. If unsuccessful after 3+1 attempts, follow the unsuccessful awake intubation algorithm 1.

Management of Unsuccessful Awake Intubation

If awake intubation fails after 3+1 attempts 1:

1. Immediately call for help 1
2. Apply 100% oxygen 1
3. Stop and reverse any sedatives 1
4. "Stop and think" while priming for emergency FONA 1

Default Action

Postpone the procedure unless airway management is immediately essential (airway compromise, urgent surgery, or expected clinical deterioration) 1.

If Proceeding is Essential

First choice: Awake front-of-neck access (cricothyroidotomy or tracheostomy) performed by most skilled available clinician 1.

If FONA inappropriate or unsuccessful: High-risk general anesthetic with 1:

• Intravenous induction with full neuromuscular blockade 1
• First intubation attempt with videolaryngoscope 1
• Formulated Plan A-D strategy based on 2015 DAS guidelines 1

Common Pitfalls to Avoid

• Attempting awake intubation in uncooperative or time-critical patients - proceed directly to induction with neuromuscular blockade instead 1
• Using inhalational induction techniques - these cause slow, difficult induction with obstruction, hypoxemia, and hypercarbia 1
• Over-sedation - risks complete airway obstruction, laryngospasm, and aspiration 1
• Inadequate topical anesthesia - leads to patient intolerance and laryngospasm 1
• Proceeding without backup plan - always have FONA equipment ready and clear failure strategy 1
• Multiple repeated attempts - causes airway trauma and edema, worsening the situation 1

Post-Intubation Considerations

Patients requiring awake fiberoptic intubation are at high risk for difficult extubation and require careful extubation planning following DAS extubation guidelines 1. Consider laryngoscopy before extubation for risk stratification, though presence of tube may alter the view 1.

Safety Profile

When performed with proper technique and preparation, awake fiberoptic intubation demonstrates high efficacy (99.4% success rate) and excellent safety (0.34% severe adverse events, no deaths or permanent consequences) across multiple protocols 4.