Airway Flashcards
Cormack and Lehane Score
Laryngoscopic view of the glottis
Grade I: most of the glottis visible
Grade II: Only the posterior portion of glottis visible
Grade III: Only epiglottis visible
Grade IV: No airway structures visualized
carina
where trachea bifurcates.
Left and right sides come off at different angles.
right bronchi is 2.5 cm long with 25 degree angle
left bronchi is 5cm long with a 45 degree angle
Thyroarytenoid
shortens and relaxes the vocal cords
Pharynx
- nasopharynx
- border is soft palate
- oropharynx
- border is the epiglottis
- includes tonsils, uvula
Glossopharyngeal (CN IX)
Vagus (CN X)
Oral airways
measure from the corner of the mouth to the earlobe
- use tongue depressor to insert
- Complications:
- laryngospasm
- bleeding
- soft tissue damage
- 2 types: Berman (BOA) and Guedel (hollow)
- small- BOA 80mm / Guedel 3
- medium- BOA 90mm / Guedel 4
- large - BOA 100mm / Guedel 5
MAC case
Monitored Anesthesia Care
- Spontaneously breathing patient
- Always have COMPLETE airway setup ready to go
- Nasal Cannula (everybody gets O2)
- 2L NC = 28% FiO2
- 6L NC = 45% FiO2
- Nasal airway if snoring
Nasal airways
measure from distance of nare to meatus of ear
- Tolerated better than oral airway with light sedation
- lubricate
- complications:
- epistaxis (nose bleed), nasal or basal scull fractures, adenoid hypertrophy
lower airway
trachea
carina
bronchi
bronchioles
terminal bronchioles
respiratory bronchioles
alveoli
Glossopharyngeal Nerve (CN IX)
- Posterior 1/3 of tongue
- soft palate
- oropharynx
Airway set up
- appropriately sized face mask
- ambu bag, circuit (for pos pres)
- suction
- tongue depressor
- oral and nasal airways
- laryngoscope handle
- 2 different blades
- ETT, 2 sizes
- stylet
- syringe
- LMA
- tape
Larynx
Located at C4-C6 in an adult
Functions: airway protection, respiration, phonation
Macintosh blade
- Inserted in vallecula above epiglottis
Optimal intubating position
“sniffing”
Oral, pharyngeal, and laryngeal axis
Most optimal for visualization of vocal cords and most effective mask ventilation
Mallampati score
Pt sitting upright, head neutral mouth open as wide as possible and tongue maximally protruded. No AAAH!
- Correlates the oropharyngeal space with the ease of direct laryngoscopy and tracheal intubation.
- When the base of the tongue is disproportionately large, the tonge overshadows the larynx resulting in difficult exposure of the vocal cords during laryngoscopy.
No AAAH!
Pre- Oxygenation
- Goal to increas O2 concentration in functional residual capacity (FRC) by “washing out” nitrogen in the FRC with O2
- 3-5 minutes of tight mask with normal breathing and 100% FiO2
- = 10 minutes of safe apnea time
- 4 vital capacity breaths within 30 seconds with 100% FiO2
- =5 minutes safe apnea time.
- 3-5 minutes of tight mask with normal breathing and 100% FiO2
glottic opening
triangular fissure between the cords
*Narrowest portion of the adult airway
Miller blade
- Inserted below epiglottis
ETT
*always have two sizes available
- Female: 6.5-7.0 mm (depth ≈ 21 cm)
- Male: 7.5-8.0 mm (depth ≈23 cm)
- Ideal position: 4 cm above carina and 2 cm below vocal cords
- All ETT have 15mm outer diameter universal connector
Trachea
Fibromuscular
10-20 cm length, 22 mm diameter
no cartilage on posterior side
bifurcates at T-4 (carina)
Lateral Cricoarytenoid
Closes the glottis
just remember where all that shit is
3 paired cartilages of Larynx
Arytenoid
Corniculate
Cuneiform
arytenoids
closes the glottis, especially posterior
Intrinsic Laryngeal muscles
- Control the movements of the laryngeal cartilages
- length and tension of cords and size of glottic opening
- Cricothyroid muscle innervated by the external branch of the superior laryngeal nerve, a branch of the Vagas nerve (CN X)
- All others innervated by the recurrent laryngeal nerve, a branch of the Vagus nerve (CN X)
- posterior cricoarytenoid
- lateral cricoarytenoid
- arytenoids
- cricothyroid
- thyroarytenoid
3 unpaired cartilages of the Larynx
Thyroid
Cricoid
Epiglottis
Thyromental Distance
- Distance from lower border of mandible to thyroid notch with neck fully extended
- Normal 4 fingerbreadths (6-6.5 cm)
- Difficult intubation <3 fingers
Nasal passage innervation
Branches of the trigeminal nerve (CN V)
Laryngospasm
Sever, sudden, sustained contraction of the glottic opening in response to stiumlus. Causes complete airway obstruction!!
Treatments:
Jaw life and mask
O2 with positive pressure
removal of stimulus
small dose of muscle relaxant Succinylcholine
Pre-op airway assessment
- general appearance
- Malampati classification
- range of motion of neck
- thyromental distance
- dentition
- mouth (lips, gums, tissues)
- mouth oppening (2-3 fingers)
- teeth (missing, protrusions, overbite, bridges out)
- size and mobility of tongue
- body habitus
- Hx of difficult intubation
*aspiration risk (hiatal hernia, GERD, recently ate, OSA)
Vocal cords
- formed by the thyroarytenoid ligaments
- appear pearly white
- attached anteriourly to the thyroid cartilage and posteriourly to the arytenoid cartilages
Nasal passage includes:
- septum
- turbinates
- adenoids
- paranasal sinuses
Cricoid cartilage
Complete cartilaginous ring
Narrowest point of the pediatric airway
inferior to thyroid cartilage and cricothyroid membrane
Trigeminal Nerve (CN V)
sensory and motor
- Hard and soft palate
- anterior 2/3 of tongue
Mallampati classes
- faucial pillars, entire uvula, soft and hard palates.
- Uvula tip masked by tongue, soft and hard palates
- Soft and hard palates, uvula base only
- Hard palate only
PUSH
pillars, uvula, soft palate, hard palate
Ensuring airway patency
- Airway maneuvers (heat tilt/chin lift, jaw thrust)
- Adjuncts (Nasal or oral airway)
- Two handed mask with bagging assistance.
**obstruction usually caused by tongue and epiglottis due to the relaxation of the genioglossus muscle
Function of nasal passage
- humidification
- filter
- warm
- *accounts for 2/3 of total upper airway resistance
posterior cricoarytenoid
muscle of the Larynx
*Separates the vocal cords and opens the gottis
LMA
- Supraglottic airway device
- used for routine AND difficult airway management
- can be used as conduit for ETT placement
- sizing based on weight
- 30-50kg–> LMA 3
- 50-70kg –> LMA 4
- 70-100kg –> LMA 5
- >100 kg –> LMA 6
- Can be used for positive pressure but is not meant for it
- only positive pressures below 15.
General anesthesia Mask case
- Can be used when:
- no difficult airway
- surgeon does not need access to head/neck
- no airway bleeding/secretions
- short case
- no position changes and easy access to head
- obstruction easily relieved with oral or nasal airway
- no neuromuscular blocker used–spontaneous breathing
Tracheal intubation indications
- airway compromise
- airway inaccessible
- long surgical time
- surgery of head, neck, cheek, or abdomen
- need for controlled venticalion and/or PEEP
- Inability to maintain airway with mask/LMA
- aspiration risk
- airway/lung disease
LMA insertion
- position head: neck flexed and head extended
- hold LMA with right hand like a pen, black line facing you
- Insert lubricated LMA into mouth, follow palate centrally, push into oropharynx until resistance is felt, then stop
- release right hand, grasp upper aspect of LMA, and attempt further advancement
- inflate the cuff (LMA will move)
- ventilate: observe, listen
- secure with tape
LMA advantages over ETT
- increased speed and ease of placement
- improved hemodynamic stability at induction and emergence
- reduced anesthetic requirements
- lower frequency of coughing during emergence
- lower incidence of sore throats
- avoids “foreigh body” in trachea
- pt can be fully emerged before removal. (good for asthma patients)
LMA disadvantages
- lower seal pressure
- high frequency of gastric insufflation
- esophageal reflux more likely
- inability to use mechanical ventilation
Potential hazards in airway management
- dental damage
- soft tissue/mechanical injury
- laryngospasm
- bronchospasm
- vomiting/aspiration
- hypoxemia/hypercarbia
- SNS stimulation
- esophageal/endobronchial intubation
- sore throat
General anesthesia LMA case
- difficult airway not present ??
- surgeon does not need access to head/neck
- no airway bleeding/secretions
- case of short duration
- more reliable patent airway than mask
- want hands free
General Anesthesia ETT case use when:
- airway compromise
- airway inaccessible
- long surgical time
- alternate surgical positions
- surgery of head, neck, cheek, or abdomen
- need for controlled ventilation and PEEP
- inability to maintain airway with mask/LMA
- aspiration risk
- airway/lung disease
