Awake fiberoptic intubation

Introduction

• This is the mainstay for securing the airway for a patient who is known to be a true difficult airway
• Studies have shown that providers who are skilled with the fiberoptic scope can intubate as quickly as one would with a video laryngoscope
• Bronchoscopes
  • Can be either rigid or flexible, however flexible is more appropriate for awake fiberoptics as it can allow for both an oral or nasal approach. We will focus on oral awake fiberoptic intubations in this article
  • Will be attached to screen to allow other parties to see the airway anatomy
  • Can be used to suction, oxygenate, or administer medications as it has a working channel

Indications

• Previously noted to be difficult intubation
• Hx of multiple failed intubation attempts
• Clinical exams that is suggestive of difficult airway (i.e. trauma, infection)
• Cervical Spine disease or inability to manipulate the neck

Anatomy/Innervation

• Glossopharyngeal Nerve
  • Supplies innervation to the oropharynx, vallecula, and base of tongue
• Vagus Nerve
  • Provides innervation the posterior pharynx, vocal cords, and trachea via two major nerve branches (Superior Laryngeal Nerve + Recurrent Laryngeal Nerve)
    • Superior Laryngeal Nerve
      • Sensory: Above the vocal cords
      • Motor: Cricothyroid Muscle
    • Recurrent Laryngeal Nerve
      • Sensory: Below the vocal cords
      • Motor: Posterior Cricoarytenoid Muscles

Preparation

• Sedation
  • The entire point of this procedure to keep the patient awake and to maintain spontaneous ventilation. Therefore, it is critical that we do not over sedate the patient and potentially cause apnea of collapse of airway structures
  • However, with the being said, this is an incredibly uncomfortable and anxiety producing procedure for patients
  • Commonly used medications:
    • Midazolam
    • Precedex
      • Can be adminsitered as either bolus or infusion
    • Remifentanil
    • Fentanyl
      • 25-50 mcg intermittent bolus can help blunt cough/gag reflex without causing significant apnea.
    • Ketamine
      • If using Ketamine, consider administering Glycopyrrolate (0.2 mg IV) to help minimize the production of secretions. It must be given atleast 20 minutes prior to intubation to see effects.
      • It can also cause patients to clench their jaw or become dissociated with the inability to follow commands
    • Propofol (low dose)
  • Of note, systematic reviews and meta analysese have shown that there is no significant difference in the success rate between all of the different medication options.
    • The only difference that was noted was that there were lower frequency of desaturations when Precedex was used.
• Localizing
  • Goal is to anesthetize the oral cavity, pharynx, larynx, and trachea (anatomy and innervation noted above)
  • The following tools can be used to localize:
    • Atomizer
      • Allows for direct spray of structures with Lidocaine 4%.
      • Target the tonsils, uvula, and vocal cords
    • Nebulizer
      • Attached to a green face mask that has Lidocaine 4% in it.
      • This will take the longest time, but can be useful for the patient to inhale if you have > 15 minutes for the nebulization to be fully effective
    • Lollipops
      • Place gauze around a tongue depressor and cover it in Lidocaine jelly/ointment. Have the patient place this as deep in their mouth as tolerated and allow them to suck on it. Every few minutes, advance the tongue depressor further as the prior portion of the pharynx should have become numb.
      • The lidocaine will melt and release droplets that will spread
    • Injection of lidocaine via fiberoptic scope
      • You can either inject from the side port of the scope or you can place an epidural catheter down the working channel and spray lidocaine via the multiple orifices at the end of the catheter
    • Other
      • You can have the patient gargle a 2% viscous lidocaine solution for 1 minute to start. This is often done in the endoscopy suite prior to EGDs
  • Nerve Blocks
    • Glossopharyngeal Nerve
      • Achieved by introducing local anesthetic near the anterior tonsillar pillars
    • Superior Laryngeal Nerve
      • Inject on either side of the greater cornu of the hyoid bone
    • Recurrent Laryngeal Nerve
      • Can be done via a transtracheal block. Needle is inserted through the cricothyroid membrane while aspirating uncle air returns. Once you have air, inject local. The patient will cough, which will help spread local anesthetic upwards.
      • Encourage the patient to suppress cough until the needle has been removed (I know, easier said than done)
• Positioning
  • Sit the patient up in a neutral position
  • Chin lift and jaw thrust can help move the soft tissue and epiglottis out of the way to help with initial placement of the fiberoptic scope.
  • It can be easier for the operator of the scope to be directly facing the patient. However, some providers like to be behind the patient. Ultimately, goal is to be in the most comfortable position.
• Other Supplies
  • Scopes of varying sizes and calibers
  • ETTs of varying sizes