Basic Airway - Dr. Hoch Flashcards
What is the ideal airway position?
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.
What happens if the airway is too extended?
the oral axis does not line up with the pharyngeal and laryngeal airway
Signs of airway obstruction
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
Describe the Thyromental Distance assessment
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.
Describe the Mallampati Assessment
○ 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)
Describe the Cormack and Lehane Grading Assessment
○ 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
Describe the Interincisor Gap Distance Assessment
How wide can the mouth be opened.
>4cm good conditions
3-4cm Fair
<3cm Warning!
Describe the Neck extension assessment
Assessing the Atlanto-Occipital Joint Mobility.
>30 degrees good
<23 degrees difficult
<10 degrees Warning!!
Describe the Upper Lip Bite Test
Evaluates temporomandibular joint.
Can the lower jaw protrude forward and bite the upper lip
Pediatric vs Adult Airway
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
Cuffed ETT sizing equation
Cuffed ETT size formula = (age/4) + 4
What acronym can help guide what makes a difficult laryngoscopy and intubation?
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
What is the 3-3-2 Rule
■ 3- fingerbreadths between upper and lower incisors
■ 3- fingerbreadths for the TMD
■ 2- fingerbreadths from the thyroid notch to hyoid bone.
Describe the MAC blade
○ 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.
Describe the Miller blade
○ 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
What separates the upper airway from the lower airway?
Cricoid Cartilage
Name 3 arteries that perfuse the nasopharynx
Maxillary A
Ophthalmic A
Facial A
What vertebrae does the nasopharynx lie near?
Lies anterior to C1
What vertebrae does the Oropharynx lie near?
C2-C3
What vertebrae does the Hypopharynx lie near?
C5-C6
Under general anesthesia what muscle relaxes and allows the tongue to fall back and obstruct the airway?
Genioglossus
Describe the topical nasal anesthesia process
■ 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
What things will inform you that the BVM ventilation is inadequate?
Minimal or no chest movement
Inadequate or no etCO2 waveform
Reduced or absent breath sounds
Decreasing SpO2
What are some complications associated with BVM ventilation
-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)
At the beginning of induction, we put the facemask on the patient, tell them to breathe for 3 minutes. We call this what?
○ 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
There are paired and unpaired cartilages of the larynx, understand which are which
a. Unpaired: thyroid, cricoid, epiglottis
b. Paired: Arytenoid, corniculate, cuneiform
Be able to match which nerve or which nerve branch does what: Trigeminal
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
Be able to match which nerve or which nerve branch does what: Glossopharyngeal
■ Anterior vallecula, oropharynx/soft palate, anterior epiglottis, posterior 1⁄3 of tongue, upper larynx, inner surface of tympanic of membrane (via lingual branch)
Be able to match which nerve or which nerve branch does what: Vagus
■ 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)
Risk factors for difficult BVM. What to do if you have difficulty
■ 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
What is a late sign of airway obstruction
○ dropped SpO2
○ Cyanosis
○ Bradycardia
○ HoTN
○ Changes in cardiac pressures
○ Changes in intracardiac shunts if present
○ Atelectasis
○ Tachycardia
○ Cardiac ischemia
○ Negative pressure pulmonary edema
You induce a patient and go to give them a breath and can’t ventilate. What would be appropriate interventions
■ 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
There are signs of upper airway obstruction (multiple); which ones would give you the greatest pause? Which one is the most ominous?
○ Upper: hoarse or muffled, difficult swallowing secretions, stridor, dyspnea
■ Stridor and dyspnea are ominous signs of severe respiratory obstruction in
hypopharyngeal and laryngeal area
