Airway Flashcards
The end of the mac blade connects to what anatomical part?
Vallecula
Mac (macintosh) vs. Miller blade
Mac is curved, miller is straight
What is the epiglottis function and where is it located
Closes during swallowing to prevent aspiration, located at C3 (end of oropharynx, start of larynx)
What are the functions of the nasal passages?
Humidify, filter, and warm
Where is the larynx and what are its functions
Larynx from C3 (epiglottis) to C6 (cricoid)
Protects airway, respiration, phonation
Nasopharynx is innervated by which nerve?
Trigeminal (CN5), opthalmic and maxillary divisions
What are the 9 cartilages that make up the larynx?
2x arytenoid, 2x corniculate, 2x cuneiform, thyroid, cricoid, epiglottis
Which nerve supplies the posterior 1/3 of tongue and oropharynx to vellecula?
CN9- Glossopharyngeal
All intrinsic muscles of the larynx are supplied by which nerve (and which branch), except for which muscle?
RLN (recurrent laryngeal nerve) of Vagus Nerve (CN X)
Exception: cricothyroid muscle is SLN (superior) on external branch
What landmark is at C6?
Cricoid cartilage
Intrinsic laryngeal muscles that adduct and abduct glottis
lateral cricoarytenoid- adduct (close)
arytenoids- adduct (close)
posterior cricoarytenoid- abduct (open)
intrinsic laryngeal muscles that put tension on vocal ligaments
cricothyroid- elongates (high pitch) vocal cords (only SLN-external!)
vocalis- shortens (low pitch) vocal cords
thyroarytenoid- shortens (low pitch) and relaxes vocal cords
extrinsic laryngeal muscles that move hyoid bone and thyroid cartilage
Sternohyoid, thyrohyoid, omohyoid - move hyoid caudad (down)
Sternothyroid - move thyroid cartilage caudad
does right or left bronchus have the smaller angle? (which are you more likely to intubate?)
Right bronchus
Mallampati’s stages
Class 1: uvula exposed (best), we see glottic opening and vocal cords
Class 2: base of uvula visible, we see glottic opening and vocal cords
Class 3: soft palate visible, we see arytenoids
Class 4: only hard palate visible, we see epiglottis only (use miller blade)
Normal Thyromental distance and what distance is considered a contributing factor to a more difficult intubation?
Thyromental distance: from lower mandible to thyroid notch, with neck fully extended, normally 6cm/ 4 fingerbreadths
difficult intubation at 3 or less fingerbreadths
For someone who is determined to be a difficult intubation, what is the alternative to giving succinylcholine?
Awake intubation with airway blocks, airway block will abolish gag reflex and hemodynamic response to laryngoscopy and bronchoscopy
Complication of putting in an oral airway
Laryngospasm!
Bleeding, soft tissue damage
2 types of oral airways
Geudel (suction through the middle is possible)
Berman
contraindications to nasal airway
basal skull fx, epistaxis, anticoagulant use
ETT size for men vs. women?
women: 6.5-7
men: 7.5-8
How far does ETT get inserted? men vs. women and proximation to carina and vocal cords
men: 23 cm
women: 21 cm
4 cm above carina, 2 cm below vocal cords
Steps of induction sequence
- preoxygenate, 2. sniffing position, 3. monitors on, 4. give induction agent, 5. lash reflex then test ventilation, 6. check neuromuscular blocking monitor (train of 4), 7. give paralytic, 8. tape eyes closed, 9. bag until loss of twitches, 10. larygoscopy and intubation, 11. confirm ETT placement, 12. keep bagging or turn on vent, 13. Start maintenance anesthetic, 14. tape ETT
Sensory and motor innervation of SLN-int branch of vagus nerve?
sensory- above vocal cords: epiglottis, tongue, supraglottic mucosa, cricothyroid joint and thyroepiglottic joint
motor- none
Sensory and motor innervation of SLN-ext branch of vagus nerve?
sensory: anterior supraglottic mucosa
motor: cricothyroid
sensory and motor of RLN branch of vagus nerve?
sensory- below vocal cords: subglottic mucosa muscle spindles
motor- intrinsic muscles of larynx (except cricothyroid is SLN-ext)
Which muscle ABDucts, closes the glottis?
Posterior cricoarytenoid
complications of airway blocks
systemic toxicity (if drug is given to vessel, aspirate to prevent this) hematoma
Transtracheal blocks which nerve, so what is blocked? (indications)
Blocks RLN branch of vagus which blocks sensory below the vocal cords, this will block the gag reflex and hemodynamic response to laryngoscopy
Steps of Transtracheal block
- skinwheel of local, 2. local to cricothyroid membrane, 3. advance 23g butterfly needle caudad through cricothyroid membrane while aspirating, 4. aspirate air to know you’re in the correct spot, 5. instruct patient to take a deep breath, 6. inject lidocaine on inspiration, 7. pt will cough, this spreads lidocaine
What nerve is blocked by superior laryngeal nerve block? What sensory areas are blocked? (indications)
SLN internal branch of vagus nerve, blocks above the vocal cords (supraglottic region), blocks gag reflex and hemodynamic response to laryngoscopy
Steps and landmarks of superior laryngeal nerve block
- palpate hyoid bone and displace toward injection site, 2. insert 23g needle perpendicular, hit hyoid bone, 3. angle needle 1/4 inch caudad and 1/4 inch medial, 4. aspirate, 5. repeat on other side
Landmarks: cornu of hyoid bone
Glossopharyngeal nerve block will block what nerves, and what sensory functions?
Lingual branch of glossopharyngeal nerve (CN 9), sensory to posterior 1/3 of tongue, this will also block gag reflex
Glossopharyngeal block steps
- use tongue blade to move tongue away, 2. insert 25g needle at base of palatoglossal arch, 0.5 cm deep and lateral, 3. aspirate, get nothing, 4. inject lidocaine, 5. repeat on other side
Cricothyrotomy: indications and contraindications
indication: emergency airway
contraindication: children under 12 and patients with laryngeal fractures
Cricothyrotomy steps
- stabilize larynx between thumb and middle finger, 2. palpate thyroid and cricoid cartilage, 3. insert 14g IV through cricothyroid membrane (1.3cm or less), angle towards carina, 4. aspirate air, 5. hook up to jet ventilator
Cricothyrotomy complications (3)
esophageal perforation (to avoid this, do not let needle advance more than 1.3cm), subcutaneous emphysema, excessive bleeding (vessel rupture)
Innervation of anterior 2/3 of tongue? Innervation of posterior 1/3 of tongue?
anterior 2/3: (taste is facial carried by chorda tympani) tactile is lingual nerve from mandibular division of trigeminal nerve (CN5).. Motor is hypoglossal
posterior 1/3: glossopharyngeal (CN9) taste and sensory (hypoglossal motor)
What physical assessments might you do to determine if the patient will be a difficult intubation? What history questions might you ask?
Physical: Mallampati, thyro-mental distance, look at surrounding tissue (burns, old trachs, mass)
History: Radiation/burn to head/neck? C-spine pain? TMJ pain? Rheumatoid arthritis? Ankylosing Spondylitis? Abcess/tumor? Prior intubations or tracheotomy? Snoring or sleep apnea? Dysphagia or stridor?
What is aligned in the “sniffing” position?
oral, pharyngeal, and laryngeal axis
What does preoxygenation consist of?
3-5 minutes of mask breathing of 100% O2 at over 5L/min
OR 4 vital capacity breaths in 30 sec (for emergencies)
What does the airway setup consist of?
Laryngoscope (2 types of blades), oral/nasal airways (several sizes), tongue depressor, ETT tube (2 sizes), suction, ambu-bag, stylet, LMA
What do the vocal cords attach to posteriorly and anteriorly?
posterior: arytenoids
anterior: thyroid cartilage
List complications of tracheal intubation
Trauma to airway Esophageal intubation Endobronchial intubation Endotracheal tube ignition Sore throat Laryngospasm Croup
