Airway Flashcards
At what level is the larynx in an adult?
C3-C6
What are the functions of the larynx?
Airway protection, respiration, phonation
What is the narrowest portion of the adult airway?
Glottic opening (triangular fissure between vocal cords)
Name the paired cartilages of the larynx.
Arytenoid - posterior attachment to VCs (with ant. a/w may be only thing visible)
Corniculate - do not play prominent role in laryngoscopic appearance or function
Cuneiform - do not play prominent role in laryngoscopic appearance or function
Name the unpaired cartilages of the larynx.
Thyroid - large and most prominent. Vocal cords anterior attachment
Cricoid
Epiglottis - covers opening to larynx during swallowing
Describe the cricoid. Why is it unique?
Complete cartilaginous, signet-shaped ring
Narrowest point of the pediatric airway
Describe the innervation of the intrinsic laryngeal muscles.
The intrinsic muscles are concerned with the movements of the laryngeal parts, making alterations in the length and tension of the vocal cords and in the size and shape.
All intrinsic muscles of the larynx are supplied by the recurrent laryngeal nerve (RLN), a branch of the VAGUS NERVE (CN-X).
**Except the cricothyroid muscle, which is supplied by the external branch of the superior laryngeal nerve.
Name the intrinsic laryngeal muscles that open and close the glottis.
Lateral Cricoarytenoid (adducts)
Arytenoids (adduct)
Posterior Cricoarytenoid
-The ONLY VC ABductors
Name the intrinsic laryngeal muscles that put tension on vocal ligaments.
Cricothyroid - also elongates vocal cords
Vocalis - Shortens the vocal cords
Thyroarytenoid - shortens and relaxes the vocal cords
List the extrinsic laryngeal muscles (muscles that move larynx as a whole).
Sternohyoid, Thyrohyoid, Omohyoid
– moves hyoid bone caudad
Sternothyroid
– moves thyroid cartilage caudad
Describe the trachea.
Fibromuscular tube 10-20 cm length & 22 mm diameter (Adult) 16-20 U shaped cartilages Posterior side lacks cartilage Bifurcates lower border T4 - carina At carina: Trachea divides into R & L mainstem bronchi Angle of R bronchus = 2.5 cm long at 25*< Angle of L bronchus = 5 cm long at 45*<
Describe an airway evaluation/history.
Assessment includes: Evaluation of the airway Surrounding tissue Pt physical characteristics Goal is to identify potential airway problems and identify a difficult airway Includes Mallampati and TMD Note: It is not one factor but a combination of factors that create the difficult airway What are questions to consider ? Radiation or burn to head/neck? C-spine pain of LROM? TMJ pain? Rheumatoid arthritis? Ankylosing spondylitis? Abscess or tumor? Prior intubation or tracheotomy? Snoring or sleep apnea? Dysphagia or stridor?
Describe the 4 classes of Mallampati.
Class I : faucil Pillars, Uvula, Soft palate, Hard palate
Class II: Uvula masked by tongue (Uvula, Soft palate, Hard palate)
Class III: Soft palate, uvula base (Soft palate, Hard palate)
Class IV: only Hard palate seen
Use PUSH mnemonic
Define thyromental distance.
Distance from lower border of mandible to thyroid notch with neck fully extended
Normal 6-6.5 cm or 4 Fingerbreadths
Difficult intubation < 3 fingers, receding mandible
What is the optimal intubating position and which three axis does it align?
“Sniffing” position- aligns the 3 axis:
oral
pharyngeal
laryngeal
Describe the two methods of pre-oxygenation.
3-5 minutes “tight” mask fit normal tidal breathing of 100% O2 > 5L/min flow = healthy patient can tolerate up to 10 minutes of apnea
4 vital capacity breaths in 30 seconds = healthy patient can tolerate up to 5 minutes of apnea
Goal = Increased O2 concentration in FRC; decreased nitrogen in FRC (79% in RA)
List items needed for an airway setup.
Laryngoscope /Blades 2 types Oral/nasal airways several sizes Tongue depressor ETT Tubes 2 sizes Suction Ambu-bag Stylet LMA (difficult airway, usually #4)
Describe the two types of oral airways, their common adult sizes, and complications/precautions.
Two types- Berman and Guedel
Adult sizes: small BOA (80 mm) = Guedel #3
medium BOA (90mm) = Guedel #4
large BOA (100mm) = Guedel #5
Complications/Precautions:
LARYNGOSPASM
Bleeding
Soft tissue damage
Explain when a nasal airway might be used, tips, common sizes, and complications.
Used to provide passageway, nose –> pharynx beneath the relaxed and obstructing tongue
Diameter-French sizes 24, 26,…36 Length- estimated as distance from nares to meatus of ear
Lubricate!
Used in series (small to large) to dilate prior to elective nasal intubation
Usually tolerated better than oral airway during light anesthesia
Complications/Precautions: epistaxis, nasal or basal skull fractures, adenoid hypertrophy, anticoagulants
List the adult male/female ETT sizes. How far down does the ETT go?
Adult ETT sizes:
Generally 2 sizes available
7.0 & 6.5 id for females
7.5 & 8.0 id for males
How far down does the ETT go?
Desirable position is 4 cm above the carina and 2 cm below the vocal cords
Males approximately 23 cm
Females approximately 21 cm
Briefly review nerves that innervate the airway, differentiating between sensory and motor.
Sensory:
Glossopharyngeal
Internal Branch Superior Laryngeal
Recurrent Laryngeal
Motor:
External Branch Superior Laryngeal
Recurrent Laryngeal
Explain the sensory innervation of the larynx.
Glossopharyngeal (9th CN)
Posterior 1/3 tongue and oropharnyx to vallecula
Internal Superior Laryngeal-
Branch of vagus - supplies sensory to vocal cords and above
Recurrent Laryngeal-
Branch of vagus - supplies mucosa below vocal cords
Explain the motor innervation of the larynx.
External Branch Sup Laryngeal-
Supplies cricothyroid muscle- puts tension on vocal cords
Recurrent Laryngeal-
Supplies ALL intrinsic muscles of larynx EXCEPT cricothyroid muscle
