1. AWAKE INTUBATION Techniques and Tips
Jennifer Ranieri
N 747
Fall 2014

2. Indication for Awake Intubation
Safety! “If they do not inspire, they expire”
Thorough preoperative history and physical evaluation
Assess difficulty with direct laryngoscopy or difficulty ventilating the patient when ablating reflexes or relaxing tissue

3. Why Awake Intubation? Maintenance of natural airway structure
Optimized gas exchange
Maintenance of muscle tone to keep relevant airway structures separated and easier to identify
Avoids anterior laryngeal movement that occurs during induction of anesthesia that potentially worsens visualization of airway structures
Tongue, vallecula, epiglottis, larynx, esophagus, posterior pharyngeal wall

4. Conditions Tumors Infections Congenital Abnormalities Foreign Body
Trauma
Obesity
Inadequate Neck Extension
Anatomic Variations
PATHOLOGIC AND ANATOMIC CONDITIONS
Tumors include: cystic hygroma, hemangioma, hematomas(head, neck, upper chest)
Infections include: submandibular abscess, peritonsillar abscess, epiglottitis
Congenital abnormalities: pierre-robin syndrome, treacher collins syndrome, laryngeal atresia, goldenhar syndrome, craniofacial dystosis,
Trauma: laryngeal fracture, mandibular or maxillary fracture, inhalational burn, cervical spine injury
Neck issues: RA, ankylosing spondylitis, halo traction
Anatomic variations: micrognathia, prognathism, large tongue, arched palate, short neck, prominent upper incisors, RADIATION or burns to the face or neck, severe overbite

5. Choices and Preparation
Preparation is key- awake intubation often more time consuming
Inform the patient
Oral versus nasal approach
Equipment selection
Anesthetizing the airway
Sedation and anxiolysis
Back up plan
Difficult airway supplies
Additional anesthesia providers
Otolaryngology at the ready
Surgical airway

6. Techniques & Equipment
Blind nasal intubation
Uses breath sounds as a guide
Awake direct laryngoscopy
Video versus traditional
Awake optical stylets
Fiberoptic scope
Transtracheal jet ventilation

7. Flexible Bronchoscope
Not a requirement for an awake intubation, but a frequent choice
Nasal or oral
Warm tube to soften, lubricate scope, keep it straight
Stepstool may help
Insufflation of O2 via the suction port allows for increased FiO2 administration during procedure
Prevents fogging, may assist in removing secretions from scope tip
Grasping tongue with gauze may assist with visualization as well as jaw thrust forward or cricoid pressure
Ovassapian airway is specially designed for FOB intubation
Protects scope from damage from biting
Patient must be well topicalized to tolerate
Disconnect ETT adapter because it will not fit through airway
Nasal FOB: nasal airway can connect 15mm adapter to circuit to provide O2 as well

8. Relevant Airway Innervation
Nose
Greater and lesser palatine nerves
Anterior ethmoidal nerve
Mouth and proximal airway structures
Glossopharyngeal
Branches of facial nerve
Larynx and distal airway structures
Vagus
Superior Laryngeal Nerve
Recurrent Laryngeal Nerve
trigeminal nerve (lingual branch of the mandibular division) also in mouth Given that it is not a part of the reflex arcs controlling gag or cough, its blockade is not essential for comfort during fiberoptic intubation.
Blocks of nasal nerves not really discussed here, according to NYSORA blocks often with basic topicalization (pledgets or reservoirs of local for min)
Nasal blocks are highly technical and huge risk of vascular injury so they are rarely done in airway management

9. Topicalization of the Airway
Mucosal application of local anesthetic to facilitate local uptake and neural blockade
May be sufficient airway anesthesia alone
Adequate application time required
May be inadequate due to pressure receptors at base of tongue causing gag reflex
Submucosal, not blocked topically

10. Topicalization Continued
Viscous lidocaine - swish and spit
Lidocaine ointment 4% “lollipop” (blob on stick), onset ~15 minutes
Nebulized lidocaine 2-4%
Highly variable results, limit inhalation to 15-30mins, well tolerated
10ml syringe with 2-4% lidocaine to atomize oral or nasal passages
Safe even if large amount swallowed
Local anesthetic soaked cotton swabs and pledgets
Cocaine excellent for this methodology but difficult to obtain plus concern about cocaine toxicity
Can add epinephrine or phenylephrine to lidocaine to achieve similar vasoconstriction
Must vasoconstrict nasal passages
Cetacaine spray: contains benzocaine, tetracaine and butamben in pressurized container
Consider risk of methemoglobinanemia with benzocaine use, 1 sec spray recommended
In summary, the maximum safe dose o lidocaine that can be topically applied to the mucous membrane of the airway is difficult to determine and must take into account the method of topicalization employed as well as the time course of administration.
Traditional dosage guidelines may be excessively conservative when some or the entire dose is administered by aerosol, based on the available evidence with respect to serum levels and toxicity occurrences.
the smallest amount of anesthetic sufficient to achieve the desired effect should be used,
Consider risk of bleeding in liver patients, anticoagulated patients or thrombocytopenia patients

11. Airway Blockade
Unfortunately, no single nerve can be blocked for adequate anesthesia to the airway
Glossopharyngeal Block (CN 9)
Anesthesia to oropharynx, tonsils, soft palate, posterior portion of the tongue, and the pharyngeal surface of the epiglottis
Superior Laryngeal Nerve Block (Branch of CN 10)
Anesthesia to base of tongue, posterior surface of epiglottis, aryepiglottic fold, and the arytenoids
Recurrent Laryngeal Nerve Block (Branch of CN 10)
Anesthesia to glottis and subglottic structures
Transtracheal Block

12. Glossopharyngeal Block
Bilateral blockade of the pharyngeal, lingual and tonsillar branches of the CN 9
Eliminates gag reflex and facilitates nasal intubation by blockade of posterior pharynx
Not adequate alone
Patient opens their mouth, gauge needle used to inject 2-4 mL of local anesthetic bilaterally at the base of the palatoglossal arch (also called the anterior tonsillar pillar)
High risk intravascular injection: aspirate and/or consider epinephrine as marker of intravascular injection
The glossopharyngeal nerve provides sensory innervation to the posterior third of the tongue, the vallecula, the anterior     surface of the epiglottis (lingual branch), the walls of the pharynx (pharyngeal branch), and the tonsils (tonsillar branch).
 It is most easily blocked where it crosses the palatoglossal arch.
 It can be blocked using one of three methods: topical spray application, direct mucosal contact of soaked pledgets, or     direct infiltration by injection.
 Glossopharyngeal nerve block is not adequate as a solo technique to facilitate intubation, but in combination with other     techniques it is highly effective.

13. Glossopharyngeal Block
The glossopharyngeal nerve provides sensory innervation to the posterior third of the tongue, the vallecula, the anteriorsurface of the epiglottis (lingual branch), the walls of the pharynx (pharyngeal branch), and the tonsils (tonsillar branch).
 It is most easily blocked where it crosses the palatoglossal arch.
 It can be blocked using one of three methods: topical spray application, direct mucosal contact of soaked pledgets, or     direct infiltration by injection.
 Glossopharyngeal nerve block is not adequate as a solo technique to facilitate intubation, but in combination with other     techniques it is highly effective.

14. Superior Laryngeal Nerve Block
Mucosal application of local anesthetic may anesthetize SLN, but if saturation time not available bilateral SLN regional blockade can be effective
The internal branch originates from the superior laryngeal nerve lateral to the greater cornu of the hyoid bone, passes approximately
2-4 mm inferior to the greater
cornu of the hyoid bone

15. SLN Block Continued
Palpate outward from the thyroid notch along the upper border of the thyroid cartilage until the greater cornu is encountered just superior to its posterolateral margin
Displace the hyoid bone with contralateral pressure by no dominating hand
This brings the ipsilateral cornu and the internal branch of the superior laryngeal nerve toward the anesthetist
Pulsation of the carotid artery being displaced deep to the palpating finger tip
Supine with head extended, identify landmarks and prep skin
Can be uncomfortable to push hyoid TOWARDS anesthetist

16. SLN Block Continued
22-25g needle is inserted until lateral aspect of the greater cornu is contacted
Walk needle downward toward the midline (1-2 mm) off the inferior border of the greater cornu
If thyrohyoid membrane is pierced then the internal branch alone is blocked
If the needle is retracted slightly after contacting the hyoid, both the internal and external branches of the superior laryngeal nerve are blocked
May result in cricothyroid muscle weakness due to lack of function as an airway dilator, but motor function of the RLN is spared and therefore does not result in clinically significant change in laryngeal inlet diameters
Negative for blood for air aspiration, inject 2ml solution and repeat on other side
Noninvasive methodology:
pledget placement in pyriform fossa
Air= needle in larynx
Blood= close proximity to vessels (carotid), take out needle and reassess high likelihood of intravasc injection
a less invasive technique for blocking the superior laryngeal nerve can be accomplished by using soaked pledgets. After topicalization, the patient is asked to stick the tongue out. The tongue is then grasped using a gauze pad.With a right-angled forceps (Jackson-Krause forceps) the anesthetic-soaked pledgets are placed in the pyriform fossae located on either side of the root of the tongue. After 5-10 minutes, a sufficient degree of anesthesia should be present for intubation

17. Recurrent Laryngeal Nerve Block
Avoidance of coughing during endotracheal tube manipulation between and below the cords
Abolition of hemodynamic responses, may help avoid vagal responses that can occur
Accomplished via the transtracheal block
Why not direct RLN blockade?
Motor innervation for all the muscles of the larynx except the cricothyroid from the RLN
Blockade will result in obstruction of airway
Sufficient blockade of the recurrent laryngeal nerve can often be accomplished using the inhalational technique previously described. Again, some patients may not achieve a sufficient amount of anesthesia to facilitate intubation.

18. Transtracheal Block Identify the cricothyroid membrane
Midline neck, palpate caudad from thyroid cartilage
Prep skin, local wheal
22- 20g needle on a 10-mL syringe with 4mL of 4% lidocaine is advanced perpendicular to the axis of the trachea and pierces the membrane
Aspirate for air, positive air identifies you are in trachea, then inject
Patient will cough! (You should have warned them of this before hand)
Coughing disperses the local anesthetic to sensory nerve endings, motor function remains intact
Rapid injection minimizes trauma to airway from needle placement and coughing, larger gauge needle may be preferable

19. Transtracheal Block

20. Intravenous Adjuncts Antimuscarinic and antisialagogue
Glycopyrrolate
Easy Reversibility and titratability
Midazolam
Fentanyl
Maintenance of Spontaneous Ventilation
Ketamine
Dexmedetomidine
Psychological Preparation
Do not use medication to compensate for poor airway anesthesia
Consider REVERSIBILITY and duration of action
Sedative agents that do not ablate spontaneous ventilation is preferable
minimize discomfort, produce anxiolysis, and attenuate recall
Patient MUST be able to follow commands

21. Glycopyrrolate Anticholinergic anti-muscarinic Antisialagogue
mg IV
Can be given IM as well
Allows better application of topic anesthetic agents
Can double the duration of lidocaine
Improves visualization
Prevents laryngovagal reflexes
Atropine would suffice, but increased risk of tachycardia and psychosis

22. Midazolam and Fentanyl
Benzodiazepine; produces anxiolysis and amnesia
0.25-4mg
Reversal: Flumazenil, imidazobenzodiazepine competitive antagonist of benzodiazepines
0.2mg over 15 sec, repeat q2min max 1mg (some sources say 3mg)
Fentanyl
Opioid agonist; sedation, analgesia, antitussive
10-100mcg
Reversal- Naloxone, competitive opioid receptor antagonist
0.4 mg/mL vial diluted in 9 mL saline to 40mcg/ml can be titrated in increments of mcg/kg (1-2ml) every 3-5 min until adequate ventilation and alertness are achieved
Increments SMALL! May help to dilute

23. Ketamine NMDA antagonist, dissociative, provides sedation
Upper airway reflexes remain largely intact, ventilatory drive minimally affected
Best as an adjunct with other amnestics and sedatives due to hallucinations
Consider cardiovascular side effects
Directly proportional to dosage
Low dose 10-50mg
GA induction dose is 1-2mg/kg

24. Dexmedetomidine Sedative, centrally acting alpha 2 agonist
Provides analgesia, anxiolysis, xerostomia, and some degree of amnesia
Maintains spontaneous respiratory rate
Consider hemodynamics
Loading dose: mcg/kg over 10 min 
 Infusion: 0.2–1 mcg/kg/hr
More selective for alpha 2 than clonidine

25. References
Benumof, J. (1991). Management of the Difficult Adult Airway With Special Emphasis on Awake Tracheal Intubation. Anesthesiology, 75(6),
Butterworth, J.F., Mackey, D.C., Wasnick, J.D. (2013). Morgan & Mikhail’s Clinical Anesthesiology. (5th Ed.). New York, NY: McGraw Hill.
Hung, O., Murphy, M.F. (2012). Management of the Difficult and Failed Airway (2nd Ed.). New York, NY: McGraw Hill.
Marcucci, C., Cohen, N.A, Metro , D.G., Kirsch, J. (2008). Avoiding Common Anesthesia Errors. Philadelphia, PA: Lippincott, Williams and Wilkins.
New York School of Regional Anesthesia. (2008). Regional & Topical Anesthesia for Endotracheal Intubation.