What is the recommended procedure for awake fibre optic intubation?

Awake Fibreoptic Intubation: Recommended Procedure

Awake fibreoptic intubation should be performed using a systematic approach incorporating adequate topical anaesthesia, minimal sedation, supplemental oxygenation (preferably high-flow nasal oxygen), and a two-point confirmation check before inducing general anaesthesia. 1

Patient Selection and Preparation

Awake fibreoptic intubation is indicated for patients with anticipated difficult airways where induction of anaesthesia could lead to a "cannot intubate, cannot ventilate" situation. 1, 2 This technique should only be attempted by suitably skilled and experienced clinicians with a clear plan for failure. 1

Pre-procedure Assessment

• Perform thorough airway assessment including Mallampati grade, neck movement, mouth opening, thyromental distance, and jaw protrusion 1
• Consider awake laryngoscopy/nasendoscopy to assess laryngoscopy view before making final decisions on technique 1
• Identify the cricothyroid membrane and mark it before starting, as part of a "double set-up" approach 1
• Ensure emergency equipment is immediately available, including cricothyroidotomy kit 1

The sTOP Framework

The Difficult Airway Society recommends using the sTOP mnemonic (sedation-Topicalisation-Oxygenation-Performance) as a cognitive aid. 1 The lowercase 's' emphasizes that sedation is optional.

Sedation (Optional and Minimal)

Use minimal sedation only if needed, as over-sedation can precipitate complete airway obstruction, laryngospasm, or critical respiratory failure. 1

• Recommended regimen: Midazolam 2 mg IV plus fentanyl 0.05-0.1 µg/kg IV immediately before bronchoscope insertion 3
• Alternative: Remifentanil and propofol target-controlled infusion (rapidly titratable, maintains spontaneous respiration) 4
• Critical caveat: Patients dependent on CPAP/PEEP are at particularly high risk of respiratory failure during awake intubation 1

Topical Anaesthesia

Adequate topical anaesthesia is essential for successful awake fibreoptic intubation. 1 Lidocaine is the preferred agent due to its favorable safety profile. 1

Antisialogogue Administration

• Glycopyrronium bromide 0.2-0.4 mg IM or 0.1-0.2 mg IV, administered 30-60 minutes pre-procedure 1
• This reduces secretions that impair visualization 1

Nasal Route Preparation (if applicable)

• Apply topical nasal vasoconstrictors (e.g., co-phenylcaine spray containing lidocaine 50 mg/mL and phenylephrine 5 mg/mL) to reduce epistaxis risk 1

Airway Topicalisation Techniques

Maximum safe dose of lidocaine is 9 mg/kg lean body weight. 1

Multiple techniques can be used, though no single technique has proven superiority: 1

• Mucosal atomisation: 4-5 mL of 4% atomised lidocaine using DeVilbiss atomiser 5
• Transtracheal injection: 4 mL of 4% lidocaine via cricothyroid membrane (faster, better patient comfort, but requires expertise) 5
• Spray-as-you-go: Periodic injection of 2% lidocaine 2-3 mL or 1% lidocaine 4-6 mL through the bronchoscope working channel 1
• Nebulisation: 4 mL of 2% lidocaine via nebulizer with face mask 3

Important: Glossopharyngeal and superior laryngeal nerve blocks are associated with higher plasma concentrations and local anaesthetic toxicity, and should be reserved for experts only. 1

Test adequacy of topicalisation atraumatically (e.g., with soft suction catheter) before airway instrumentation. 1

Oxygenation

High-flow nasal oxygen (HFNO) should be the technique of choice if available, as it reduces desaturation incidence to 0-1.5% compared to 12-16% with low-flow oxygen. 1

• Start supplemental oxygen on patient arrival and continue throughout the procedure 1
• HFNO at 50-60 L/min provides optimal oxygenation 1
• Alternative: Standard nasal cannulae or facemask if HFNO unavailable 1

Patient Positioning

Position the patient sitting upright or in anti-Trendelenburg position with head elevated. 1, 3 This optimizes respiratory mechanics and reduces aspiration risk. 1

Performance of Intubation

Route Selection

Choose between nasal and oral routes based on patient factors, operator skill, and equipment availability—neither route has proven superiority. 1

• Nasal route considerations: Better tolerated, but requires vasoconstriction, may cause epistaxis, typically requires subsequent conversion to oral tube 1
• Oral route considerations: Preferred if nasal bleeding risk is high or immediate oral tube placement needed 1

Technique Selection

Awake tracheal intubation via flexible bronchoscopy (ATI:FB) and videolaryngoscopy (ATI:VL) have comparable success rates (98.3% each). 1

• ATI:FB preferred for: Limited mouth opening, large tongue, fixed neck flexion deformity 1
• ATI:VL preferred for: Airway bleeding, when blood/secretions present 1
• Consider combined approach using both VL and FB in complex scenarios 1
• Single-use flexible bronchoscopes have similar safety profile to reusable ones 1

Intubation Steps

1. Insert bronchoscope gently through prepared nostril or oral cavity 3
2. Identify the carina before advancing the tracheal tube to minimize misplacement risk 1
3. Advance endotracheal tube over bronchoscope while maintaining visualization 1
4. Confirm appropriate distance from tube tip to carina before removing bronchoscope 1
5. Remove bronchoscope carefully with tip in neutral position while holding tube firmly 1

Two-Point Confirmation Check

Before inducing general anaesthesia, perform mandatory two-point confirmation: 1, 6

1. Visual confirmation: Direct visualization of tracheal lumen with bronchoscope OR tracheal tube through vocal cords with videolaryngoscope 1
2. Capnography: Waveform capnography to exclude oesophageal intubation (100% sensitivity and specificity in spontaneously breathing patients) 1, 6

Critical warning: In spontaneously breathing patients, capnography may show a trace with supraglottic or bronchial placement, making visual confirmation essential. 1

Timing of Cuff Inflation and Anaesthesia Induction

• Tracheal tube cuff can be inflated before, during, or after induction 1
• Base timing decision on relative risks of aspiration, patient movement, coughing, and tube displacement 1
• If cuff tear is suspected, gently inflate to check integrity before induction 1
• Induce anaesthesia only after two-point check confirms correct placement 1

Common Pitfalls and How to Avoid Them

Critical Complications to Anticipate

Awake techniques may precipitate complete airway obstruction from over-sedation, topical anaesthesia, laryngospasm, or bleeding. 1, 7 This is why minimal sedation and adequate preparation are essential.

• Blood, secretions, vomitus: Severely hamper visualization with both fibreoptic and videolaryngoscopy 1
• Oesophageal intubation: Occurs in 2.3% of ATI:FB and 4.9% of ATI:VL procedures 1
• Aspiration risk: Present throughout procedure, particularly in critically ill patients 1

Specific Avoidance Strategies

• Never proceed without adequate topicalisation testing 1
• Limit sedation to absolute minimum needed for patient comfort 1
• Have immediate access to front-of-neck airway equipment 1
• If first technique fails, consider alternative approach (e.g., switch from ATI:VL to ATI:FB or vice versa) 1
• In critically ill patients: Balance practicality of awake technique against potential success after induction of anaesthesia 1

Special Populations

In critically ill patients, awake intubation has significant limitations including time-critical situations, limited patient cooperation, and risk of precipitating complete respiratory failure. 1 Consider intravenous induction with full neuromuscular blockade and "double set-up" for front-of-neck access as an alternative. 1