Airway Flashcards
Nine cartilages of larynx
Unpaired: Epiglottis, Thyroid, Cricoid
Paired: Arytenoid, Corniculate, Cuneiform
Cranial Nerves that innervate muscles of pharynx, larynx, soft palate
IX: Glossopharyngeal
X: Vagus
XI: Spinal accessory
Superior Laryngeal Nerve Sensory/Motor innervation
Internal: Sensory to all larynx above TVCs
External: Motor to cricothyroid muscle
Recurrent Laryngeal Nerve Sensory/Motor innervation
Motor to all larynx muscles except cricothyroid
Sensory to TVCs, trachea
Triangular intubation axes
Align oral axis, pharyngeal axis, and laryngeal axis
Lemon law airway assessment
L=Look externally (0-4pts) E=Evaluate 3-3-2 (0-3pts) M=Mallampati O=Obstruction (0-1pt) N=Neck mobility (0-1pt) Score 0-9 points, higher score means possibly more difficult airway
Formula to size pediatric ETT
Age/4 + 4
-1/2 size for cuffed tube
Age=most reliable indicator of appropriate tube size for children
____ separates the upper and lower airway
Cricoid cartilage
Upper airway components (5 parts)
Nose Mouth Pharynx Hypopharynx Larynx
Lower airway components (5 parts)
Trachea Bronchi Bronchioles Respiratory bronchioles Alveoli
Hard vs soft palate
Hard
-Stationary
Soft
-Posterior 1/2 of oral cavity
-Rises during eating to prevent aspiration
-Sleep/paralytic can cause it to obstruct the nasal passage
Pharynx (overall structure and 2 compartments)
- Extends from the base of the skull to the cricoid cartilage
- Nasopharynx, oropharynx, and hypopharynx
Cricothyroid membrane
Only complete cartilaginous ring in the airway
-Connects cricoid cartilage at C6 to the thyroid cartilage
Vocal folds (name, anatomy)
True vocal cords
-Attach anteriorly to the thyroid cartilage and posteriorly to the arytenoids
Space between vocal folds
Rima glottidis, goes to the trachea
Vestibular folds
False vocal cords, around the vocal folds/true vocal cords
Superior valeculla
Space between base of tongue and epiglottis
-Applying force here pulls the epiglottis away from the glottis opening
Inferior valeculla
Between the inferior ridge of the epiglottis and true vocal cords
Epiglottis
Single leaf like cartilage, sits above the glottic opening (to the larynx)
- Closes during swallowing
- Attached to the upper border of the hyoid bone
Direct laryngoscopy anatomy
- Larynx starts at epiglottis
- Internal to larynx=articulating cartilages, arytenoids, epiglottis
- Epiglottis, superior, and interior valeculla
Larynx (C space and number of cartilages)
- Starts at C4-5 in adults, ends at C6
- 3 single cartilages
- 3 paired cartilages
Branches of Recurrent laryngeal nerve
Right-subclavian
Left-aortic arch
Vagus nerve supply and branches
Sensation below the epiglottis
-2 branches innervate the hypopharynx: Superior laryngeal nerve, Recurrent laryngeal nerve
RLN injury
- Acute bilateral injury=risk for stridor and respiratory distress
- Unilateral or chronic injury isn’t as dangerous
Larynx muscles
Intrinsic
-Moves individual components of the larynx
-Provides functional movement of cartilages and the vocal cords
Extrinsic
-Moves larynx as a whole in the neck superiorly and inferiorly
Cricothyroid muscle
“Cords tense”
-Tense vocal cords
Thyroarytenoid muscle
“They relax”
- Relax vocal cords
- Adductor
Posterior Cricoarytenoid muscle
“Please come apart”
-Abductor to vocal cords
Lateral cricoarytenoid muscles
“Lets close away”
-Adductor for vocal cords
Interior arytenoid muscle
- Closes glottis
- Adductor
Larynx blood supply
- From branches of the thyroid arteries
- Superior laryngeal artery: Top 1/2 of larynx, branch of the superior thyroid artery off the external carotid
- Inferior laryngeal artery: Branch of the inferior thyroid artery off the subclavian artery
Trigeminal nerve (#, sensory, motor)
CN V V1: Opthalmic V2: Maxillary V3: Mandibular Sensory: Nares, anterior 1/3 of septum, turbinates, anterior 2/3 of tongue Motor: 0
Glossopharyngeal nerve (#, sensory, motor)
CN IX
Sensory:
-Posterior 1/3 of tongue, anterior epiglottis, oropharynx, pharynx, soft palate, tonsils, valeculla
Motor: 0
Superior laryngeal nerve (#, sensory, motor)
CN X External -Sensory: 0 -Motor: Cricothyroid (tense VCs) Internal -Sensory: Larynx above TVCs, post of epiglottis -Motor: 0
Recurrent laryngeal nerve (#, sensory, motor)
CN X
Sensory: Below VCs: larynx and trachea
Motor: Larynx, all intrinsic muscles except cricothyroid
Carina
Lower part of trachea, richly innervated
-Sensitive to sensory stimulation
Mallampati classification
-Indirect method of relating the size of the base of the tongue to the oral cavity
Mallampati 2 = ____ hidden
Tonsillary pillars are hidden by tongue
Mallampati 3
Only the base of the uvula is seen
3-3-2 rule
- Mouth should open at least 3 fingerbreadths
- Thyromental distance (chin to hyoid) <3 fingerbreadths is difficult
- 2 fingerbreadths between the hyoid bone and thyroid notch
Too short of an oral airway = ____
Pushes posterior tongue against the post pharyngeal wall = obstruction/trauma
Too long of an oral airway = ____
Causes airway obstruction to laryngeal inlet by compressing the epiglottis = trauma/laryngospasm
Nasal airway contraindication
- Anticoagulated
- Sepsis
- Children with prominent adenoids
- Caution in patients with basilar skull fractures
Inadequate mask ventilation (cause, steps to take)
- Due to decreased compliance and increased resistance
- Place an OA/NA
- 2 handed BMV
- Intubate or place SGA
ETT size - what does it mean
Inner diameter size
- Most important in resistance to fresh gas flow
- Effects resistance much more than the length of the tube
Murphy eye
Additional distal opening in the side of the ETT
- Ventilation port if the distal end is obstructed
- Decreased trauma during nasal intubation
ETT size range and pressure to check cuff leak for pediatric tubes
- 5 - 8.5
- Cuff leak at 20-30 cmH2O
ETT size and depth for adults
Male: 7.0-8.0mm, 23cm
Female: 6.5-7.0mm, 21cm
Normal tracheal wall pressure
15-30 mmHg
Type of cuff recommended for ETT
High volume low pressure
-Decreases risk of mucosal damage
Reinforced ETT
Used when a standard tube would be likely to kink
Oral RAE ETT
Used in ENT surgery to provide full access to the face, taped to lower lip
Nasal RAE ETT
Used in oral surgery
Laser ETT
Covered with nonflammable material, some made of metal
Macintosh blade inserted ____
In vallecular fold
-Lifting motion elevates the epiglottis and uncovers the vocal cords
Miller blade used to ____
Lift the epiglottis and compress it against the base of the tongue
Phillips blade
Used for peds age 2-6
Provides great visibility directly to the trachea
-Strait Jackson blade design with curved distal tip
Wisconsin blade
Increases the visual field and decreases the possibility of trauma
-Strait spatula, flange expands slightly toward the distal blade
BURP maneuver
- Backward, Upward, Rightward Pressure on thyroid cartilage
- Displaces larynx, may improve visualization of the glottis
Verify ETT placement
Bilateral chest rise
Bilateral breath sounds
Auscultate stomach
ETCO2
Preoxygenation before RSI
Healthy patient: Four maximal breaths
Patient with lung disease: 3-5 minutes
RSI ETT size
1/2 size smaller than normal
-Use ETT with stylet to maximize chance of easy intubation
Modified RSI
Allows for gentle ventilation with cricoid pressure maintained
LMA intracuff pressure
<60 cmH2O
LMA maximum airway seal pressures
- Classic LMA: <30cmH2O
- ProSeal, Supreme LMA: 40cmH2O
- Limit TV to 8mL/kg
Double lumen ETT indications
- Thoracic procedures
- Control of contamination or hemorrhage
- Unilateral pathology (bronchopleural or bronchocutaneous fistula, large cyst/bullae, different compliance)
McGrath MAC video laryngoscope
Has a video display mounted on the handle
-Sizes 2, 3, 4 correspond to Mac blades
Patients at risk of aspiration
- Full stomach
- GERD
- Hiatal hernia
- NG
- Morbid obesity
- DM
- Pregnancy
- Use of narcotics
Preventing aspiration
- Antacid preop (bicitra)
- Reglan
- Cricoid pressure
- Mild reverse trendelenberg
- Working suction
Laryngospasm
Spasm of laryngeal musculature
-Caused by sensory stimulation by vagus nerve (external branch of SLN or RLN)
