Basic Airway - Dr. Hoch

Question 1

What is the ideal airway position?

Answer 1

Sniffing position. Optimal positioning is observed when an imaginary horizontal line can be drawn from the sternal notch, extending anteriorly to the ear or tragus.

Question 2

What happens if the airway is too extended?

Answer 2

the oral axis does not line up with the pharyngeal and laryngeal airway

Question 3

Signs of airway obstruction

Answer 3

Upper Airway:
A hoarse or muffled voice
Difficulty swallowing secretions
Stridor
Dyspnea

Lower Airway:
High peak airway pressures
low tidal volumes
impaired ventilation

■ etCO2 tracing (shark fin)
■ Fog in the mask/lack thereof
■ Tactile – feel the air move
■ Sound of air moving/inspiratory
stridor
■ Accessory muscle retraction
■ Precordial stethoscope
■ Desaturation

Question 4

Describe the Thyromental Distance assessment

Answer 4

Measures the thyromental space and indicates how much room the tongue has to be displaced during laryngoscopy.
■ Measured from the thyroid notch to the lower border of the
mentum when the head is extended and the mouth is closed.
■ A TMD less than 6 cm can hinder tongue displacement.
■ A TMD greater than 9 cm can indicate a large hypopharyngeal
tongue, caudal larynx, or a longer mandibulo-hyoid distance.

Question 5

Describe the Mallampati Assessment

Answer 5

○ Used to assess mouth opening, tongue and oral pharynx size, and posterior oropharyngeal
structures.
○ Patient to be sitting up, extend the neck, and protrude tongue without phonation

Class I- pillars, uvula, soft palate, hard palate, fauces (PUSH)
Class II- soft palate, fauces, uvula (USH)
Class III- soft palate, hard palate, base of uvula (SH)
Class IV- hard palate only (H)

Question 6

Describe the Cormack and Lehane Grading Assessment

Answer 6

○ Offers an objective assessment of the pharyngeal structures, glottic structures, and glottic opening during laryngoscopy
● Grade I- full view of the glottic opening
● Grade IIa- partial view of the vocal cords, full view of posterior laryngeal cartilages
● Grade IIb- only posterior portion of glottic opening
● Grade III- only the epiglottis can be visualized
● Grade IV- epiglottis cannot be seen
*Grade III & IV associated with difficult intubation

Question 7

Describe the Interincisor Gap Distance Assessment

Answer 7

How wide can the mouth be opened.
>4cm good conditions
3-4cm Fair
<3cm Warning!

Question 8

Describe the Neck extension assessment

Answer 8

Assessing the Atlanto-Occipital Joint Mobility.
>30 degrees good
<23 degrees difficult
<10 degrees Warning!!

Question 9

Describe the Upper Lip Bite Test

Answer 9

Evaluates temporomandibular joint.
Can the lower jaw protrude forward and bite the upper lip

Question 10

Pediatric vs Adult Airway

Answer 10

Kids airway resembles adults around age 12-14.

-Kids have larger tongues concerning the oral cavity
-Epiglottis is larger and more stiff. (why we usually use Miller blades on kids)
-Cricoid cartilage is the narrowest part of airway, compared to vocal cords in adults
-Funnel-shaped, adults cylinder chapped
-More prone to laryngospasm and Croup

Question 11

Cuffed ETT sizing equation

Answer 11

Cuffed ETT size formula = (age/4) + 4

Question 12

What acronym can help guide what makes a difficult laryngoscopy and intubation?

Answer 12

LEMONS
L: look externally. (shape of face, obesity, head and neck pathophysiology)
E: Evaluate 3-3-2 rule
M: Mallampati Score
O: Obstruction (indications for upper or lower airway obstruction)
N: Neck Mobility

Question 13

What is the 3-3-2 Rule

Answer 13

■ 3- fingerbreadths between upper and lower incisors
■ 3- fingerbreadths for the TMD
■ 2- fingerbreadths from the thyroid notch to hyoid bone.

Question 14

Describe the MAC blade

Answer 14

○ Curved laryngoscope blade
○ Place the tip of the laryngoscope in the vallecula, apply tension to the hypoepiglottic ligament using a gentle lifting force,
promoting the indirect elevation of the
epiglottis.

Question 15

Describe the Miller blade

Answer 15

○ Straight laryngoscope blade
○ Place the tip of the laryngoscope posterior to the epiglottis and apply gentle force to directly lift the epiglottis.
○ Good for pediatrics or deeper airways

Question 16

What separates the upper airway from the lower airway?

Answer 16

Cricoid Cartilage

Question 17

Name 3 arteries that perfuse the nasopharynx

Answer 17

Maxillary A
Ophthalmic A
Facial A

Question 18

What vertebrae does the nasopharynx lie near?

Answer 18

Lies anterior to C1

Question 19

What vertebrae does the Oropharynx lie near?

Answer 19

C2-C3

Question 20

What vertebrae does the Hypopharynx lie near?

Answer 20

C5-C6

Question 21

Under general anesthesia what muscle relaxes and allows the tongue to fall back and obstruct the airway?

Answer 21

Genioglossus

Question 22

Describe the topical nasal anesthesia process

Answer 22

■ Nasal septum, wall, and nasopharynx (5ml viscus lidocaine each nare)
■ 4-10 ml of Lidocaine 4% with phenylephrine 1% 1ml in nebulizer
● Small drops get deposited into lower airway
■ Topical atomization 5-8 big breaths through nose/mouth
● Denser block than nebulizer, stays higher

Question 23

What things will inform you that the BVM ventilation is inadequate?

Answer 23

Minimal or no chest movement
Inadequate or no etCO2 waveform
Reduced or absent breath sounds
Decreasing SpO2

Question 24

What are some complications associated with BVM ventilation

Answer 24

-Poor Seal
○ Pressure sores, skin erosions from too much pressure on the mask
○ Nerve injury from mask strap (usually transient to facial CN 7)
○ Aspiration (unprotected airway)
○ Eye injury (if incorrect fit of mask)

Question 25

At the beginning of induction, we put the facemask on the patient, tell them to breathe for 3 minutes. We call this what?

Answer 25

○ Preoxygenation/denitrogenation (per Blake), hyperoxygenation…
○ Apneic oxygenation
○ Use NC or facemask up to 15 L/min to drive oxygen into hypopharynx and entrain into trachea

Question 26

There are paired and unpaired cartilages of the larynx, understand which are which

Answer 26

a. Unpaired: thyroid, cricoid, epiglottis
b. Paired: Arytenoid, corniculate, cuneiform

Question 27

Be able to match which nerve or which nerve branch does what: Trigeminal

Answer 27

Trigeminal (CN 5)
■ Ophthalmic (V1) - nares, anterior 1⁄3 of nasal septum
■ Maxillary (V2) - turbinates, posterior 2⁄3 of nasal septum
■ Mandibular (V3) - anterior 2⁄3 tongue

Question 28

Be able to match which nerve or which nerve branch does what: Glossopharyngeal

Answer 28

■ Anterior vallecula, oropharynx/soft palate, anterior epiglottis, posterior 1⁄3 of tongue, upper larynx, inner surface of tympanic of membrane (via lingual branch)

Question 29

Be able to match which nerve or which nerve branch does what: Vagus

Answer 29

■ SLN
● Internal - sensory input to hypopharynx above vocal cords. Including posterior epiglottis
● External- motor to the cricothyroid muscle

■ RLN
● Motor
-Intrinsic muscles of the larynx (except cricothyroid m.)
Lateral cricoarytenoid
Posterior cricoarytenoid
Vocalis
Thyroarytenoid
Aryepiglottic
Interarytenoid
● Sensory - subglottic area & trachea (below cords)

Question 30

Risk factors for difficult BVM. What to do if you have difficulty

Answer 30

■ BONES – beard, obese (BMI > 40), no teeth, elderly (> 55), snoring (OSA)
■ If run into difficulty with BMV, can place OPA, NPA, ask for assistance, head tilt jaw thrust,
work on seal

Question 31

What is a late sign of airway obstruction

Answer 31

○ dropped SpO2
○ Cyanosis
○ Bradycardia
○ HoTN
○ Changes in cardiac pressures
○ Changes in intracardiac shunts if present
○ Atelectasis
○ Tachycardia
○ Cardiac ischemia
○ Negative pressure pulmonary edema

Question 32

You induce a patient and go to give them a breath and can’t ventilate. What would be appropriate interventions

Answer 32

■ Correct obstruction
● Correcting an airway obstruction:
● Head tilt chin lift
● Jaw Thrust
● Airways – Nasal and oropharyngeal
● Pressure support with ambu
● LMA
● Tracheal intubation
● Transtracheal jet
ventilation/Cricothyrotomy
● Jaw thrust, chin lift
■ Place SAD/LMA
■ Wake them up (consider)
■ Call for help
■ Attempt intubation if not previously attempted
● Limit attempts to 2-3
■ Can’t ventilate/can’t intubate → surgical
■ Try for 5-10 minutes

Question 33

There are signs of upper airway obstruction (multiple); which ones would give you the greatest pause? Which one is the most ominous?

Answer 33

○ Upper: hoarse or muffled, difficult swallowing secretions, stridor, dyspnea
■ Stridor and dyspnea are ominous signs of severe respiratory obstruction in
hypopharyngeal and laryngeal area