AWAKE INTUBATIONTechniques and Tips

Jennifer Ranieri

N 747

Fall 2014

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

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

Conditions

• Tumors

• Infections

• Congenital Abnormalities

• Foreign Body

• Trauma

• Obesity

• Inadequate Neck Extension

• Anatomic Variations

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

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

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

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

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

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

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

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, 22-25 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

Glossopharyngeal Block

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

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

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

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

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

Transtracheal Block

Intravenous Adjuncts• Antimuscarinic and antisialagogue

– Glycopyrrolate

• Easy Reversibility and titratability

– Midazolam

– Fentanyl

• Maintenance of Spontaneous Ventilation

– Ketamine

– Dexmedetomidine

• Psychological Preparation

Glycopyrrolate• Anticholinergic anti-muscarinic

• Antisialagogue

• 0.2-0.4mg 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

Midazolam and Fentanyl• Midazolam

– 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 0.5-1 mcg/kg (1-2ml) every 3-5 min

until adequate ventilation and alertness are achieved

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

Dexmedetomidine

• Sedative, centrally acting alpha 2

agonist

– Provides analgesia, anxiolysis, xerostomia,

and some degree of amnesia

• Maintains spontaneous respiratory rate

• Consider hemodynamics

• Loading dose: 0.5-1 mcg/kg over 10

min  Infusion: 0.2–1 mcg/kg/hr

References• Benumof, J. (1991). Management of the Difficult Adult Airway With

Special Emphasis on Awake Tracheal Intubation. Anesthesiology,

75(6), 1087-1110.

• 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. http

://www.nysora.com/techniques/nerve-stimulator-and-surface-based-r

a-techniques/head-and-neck-blocka/3022-regional-topical-anesthesi

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