Airway lecture Flashcards
Nasal passages includes, function, innervation
Includes
1) Septum
2) Turbinates
3) Adenoids
Function -accounts 2/3 airway resistance Humidifies Filter Warm
Innervation
-Trigeminal nerve (CN V)
Oral Cavity includes…
Teeth, tongue, hard palate, soft palate
Innervation of trigeminal nerve
Hard/soft palate
Anterior 2/3 tongue
Innervation of glossopharyngeal
Posterior 1/3 tongue
Soft palate
Oropharynx
Nasopharynx
Border is soft palate
Oropharynx
Border is epiglottis. INcludes tonsils/uvula
3 divisions of upper airway
Nasopharynx, oropharynx, hypopharynx/laryngopharynx
Innervation of pharynx
Glossopharyngeal and vagus
Larynx location in adult (c level>)
C4-C6 in adult
Function of larynx
Airway protection
Respiration
Phonation
Name the 3 paired cartilages of larynx
Arytenoid
Corniculate
Cuneiform
3 unpaired cartilages in larynx
Thyroid
Cricoid
Epiglottis
Where is a cricothotomy done?
Cricothyroid ligament
Thyroid cartilage
Large and most prominent
Anterior attachment for vocal cords
Epiglottis
Covers opening to larynx during swallowing
Cricoid cartilage
Only complete ring
Narrowest point of pediatric airway
Arytenoid cartilage
Posterior attachment for vocal cords
Falsely id’ed in anterior airway
Corniculate
Posterior portion of aryepiglottic fold
Cuneiform
Not always present. Lateral to corniculates
Vocal cords
Appear pearly white
Formed by thyroarytenoid ligaments
Attached anteriorly to thyroid cartilage and posteriorly to arytenoid cartilages
Glottis Opening
Triangular fissure b/w cords
Narrowest point of adult airway
Lateral Cricoarytenoid muscle
Addictive vocal cords
Let’s close airway. Glottis opening
Posterior cricoarytenoid muscle
Only vocal cord abductors. Pull cords open. GLottic opening
Arytenoid muscles
ADDUCTS vocal cords.
Consists of oblique arytenoid s and transverse arytenoids
Controls glottis closure
Laryngeal muscles for vocal cord length
Cricothyroid, thryoarytenoid, vocalis
Cricothyroid muscle
Tenses/elongates vocal cords
Thyroarytenoid muscle
Relaxes/shortens vocal cords
Vocalis muscle
Relaxes/shortens vocal cords
Cricothyroid muscle innervation by
External branch of superior laryngeal nerve branch of vagus nerve
All laryngeal muscles besides cricothyroid muscle are innervation by…
Recurrent laryngeal nerve branch of vagus nerve
Suprahyoid group consists of and does what to larynx?
Stylohyoid
Mylohyoid
Geniohyoid
Digastric
Raises larynx cephalad
Infrahyoid group consists of what and does what to larynx?
Sternothyroid,
Sternohyoid
Thyrohyoid
Omohyoid
Moves larynx caudad
Lower airway consists of
Trachea, Carina Bronchi Brochioles Terminal bronchioles Respiratory bronichioles Alveoli
Trachea
Begins at level of cricoid cartilage and extends to carina.
10-15 cm in length in adult. Diameter of 22mm in adult
16-20 c shaped cartilaginous rings that open poseriorly.
Posterior side has no cartilage
Bifurcated at T4- carina
Carina
T4 BIFURCATION
Airway assessment
General appearance - head, neck size, fullness ROM Dentition Mouth - tongue, lips, gums Mouth opening 2-3 fingers (30-40mm) Body habit us Mallampati Thyromental distance Mandibular protrusion test (bite lip with bottom teeth) Hx previous difficult airway Diagnosis Planned sx
Assessment of mallampati
- correlates oropharynx earl space with ease of DL and tracheal intubation Assessment- Pt sits upright Head neutral Mouth open Tongue maximally protruded NO AHH!
Class I mallampati
PUSH Pillars Uvula(entire) Soft palat Hard palate
Class II mallampati
Uvula tip masked by tongue
Soft palate
Hard palate
Class III mallampati
Soft palate
Hard palate
(Uvula base only)
Class IV mallampati
Hard palate only
Cormack and Lehane score
Laryngoscopic view of glottis
Grade I cormack and lehane
Most of glottis visible
Grade II cormack an lehane
Posterior portion of glottis visible
Grade III Cormack and Lehane
Only epiglottis visible
Grade IV Cormack and Lehane
No airway structures visible
THyromental distance
Distance from lower border of mandible to thyroid notch with neck fully extended.
Normal 6-6.5 cm or 4 fingerbreadths.
If <3 fingers, receding mandible and possible difficult airway
Mandibular protrusion test
Ability to align teeth
Class A mandibular protrusion test
Lower incisors can be protruded anterior to upper incisors
Class B MPT
Lower incisors brought edge to edge
Class C MPT
Lower incisors cannot be brought edge to edge with upper incisors
What do you need to prepare for induction?
Ms. MAIDS Monitors on and settings appropriate Suction on and at HOB Machine checked, +pressure ventilation Airway IV Drugs Special equipment
What is preoxygenation and how do you achieve it?
Goal is to increase O2 concentration and “wash out” nitrogen in the FRC with oxygen.
Takes 3-5 min “tight mask” with normal tidal breathing with 100% Fio2 at >6L/min flow= 10 minutes of safe apnea time
4 vital capacity breaths within 30 seconds at 100% fio2 >6l/min= 5 minutes safe apnea time
8 breaths over 60 seconds will >effectiveness over 4 br/30 sec
ET concentration oxygen >90% maximizes apnea time. High metabolic rate needs more time
When are you at increased risk for aspiration?
Loss of AW reflexes High risk: -full stomach -symptomatic GERD -Hiatal hernia -Presence of NG tube -morbid obesity - DM -Gastroparesis -Pregnancy
What do you need for airway setup?
LOST SEAL? Laryngoscopes +2 blades Oral airway S suction T -tape and tongue depressor S- syringe and styled E- ETT tube +2 sizes A- ambu bag L-LMA w lube
What can make a difficult mask fit?
Beard Edentulous Short mandible OSA Males BMI <30 Mallampati III or IV AGE >55
How do you know you are mask ventilating well?
Effectiveness determined by chest rise, exhaled TV, pulse ox, capnography
TV need to be achieved with peak inspiratory pressure <20
Higher pressures can cause gastric insufflation
Common obstruction during mask ventilation?
Tongue and epiglottis! D/t relaxation of genioglossus muscle
Oral airways
2 types- German and Guedes. Guedel has hole down center
Measure from corner of pt mouth to angle of jaw or earlobe
Compilation/precautions in oral airways?
Laryngospasm Bleeding Soft tissue damage Lingual nerve palsy Damage to teeth Worsening obstructions
Nasal airway
Nose—> pharynx beneath relaxed and obstructing tongue
Estimate distance nares to meatus of ear
Lubricate!
Can dilate with smaller sizes
Complications/ precautions of NPA
Epistaxis
Nasal/nasal skull fractures
Adenoid hypertophy
Anticoags
What is a Laryngospasm
Provoked by glossopharyngeal or vagal stimulation attributable to airway instrumentation or vocal cord irritation, in the settting of light anesthesia.
-can also be precipitated by other noxious stimuli and can persist well after removal of stimulas
Treatment of laryngospasm
Removal of airway irritants Deepening of anesthetic Admin NMB (sucks) Treatment CPAP 100% O2 BiLATERAL pressure at laryngospasm notch (b/w condyle of mandible and mastoid process)
What is a bronchospasm
Irritation of lower airway by foreign substance.
Activates a vagal reflex- mediated constriction of bronchial smooth muscle.
Treatment of bronchospasm
Depending anesthetic with proposal/volatile agent
Admin b2 agonist or anticholinergic
Potential hazards to advanced airway management
- dental damage
- soft tissue injury
- laryngospasm
- bronchospasm
- vomiting/aspiration
- hypoxemia and hypercarbia
- SNS stimulation
- esophageal intubation
Dentist injured Larry’s bright veneer, he sued everyone
Predictors of difficult intubation
- long upper incisors
- prominent overbite
- inability to protrude mandible
- small mouth opening
- mallampati III or IV
- high, arched palate
- short thyromental distance
- short, thick neck
- limited cervical mobility
MAC
Generally chosen with adults
Less likely to cause dental damage. Grabs vallecula
3 is average size adults
Miller
Straight blades generally used in kids
Also good to use for people with short thyromental distance
Grabs epiglottis
2-average size adults
What are absolute indications for ETT?
Full stomach High risk aspiration Critically ill Sig lung abnormalities Sx requiring lung isolation ENT sx where SGA interferes with sx access Failed SGA placement
Other
- NMBDs
- positioning that does not allow access to AW
- predicted difficult airway
- prolonged procedures
Common features of ETT
Standard 15 mm adapter
High volume- low pressure cuff to protect against gastric aspiration
Beveled tip passes through vocal cords easily
Murphy eye has back-up in case of occlusion
Pilot balloon with one way valve for cuff inflation 4-5 cc fine, Air leak 20-25 cm H20
Ideal position for ETT based on ETT size? M/F?
Id X3= APPROXIMATE depth
Generally 6.5-7 for female, 7.5-8 for male
Ideal position of ETT inside trachea
4 cm above carina, 2 cm below vocal cords
Optimal intubating position
Sniffing position. Align 3 axis
Oral axis
Pharyngeal axis
Laryngeal axis
LMA purposes?
A Supraglottic airway (SGA) that can be used as
1) primary AW device,
2) rescue device,
3) or conduit for ett
Appropriate size LMA?
Based on weight 30-50 kg—> LMA 3 50-70 KG—> LMA 4 70-100 kg —> LMA 5 >100 LMA 6
Amoung airway pressure we can ventilate LMA with?
20 cm H2O
Inserting LMA
Adequate anesthesia depth is critical
Deflate cuff and lub posterior aspect
Inflate with min volume air (target cuff pressure 40-60 cm h2o)
Confirm with gentle PPV, Cagnography, auscultation
- leak audible at inspiratory pressure 18-20cmH2O
Advantages of LMA over ETT
- increased speed and ease of placement by inexperienced personnel
- improved hemodynamics stability at induction and emergence
- reduced anesthetic requirement
- lower frequency of coughing during emergence
- lower incidence of sore throats
Disadvantages of LMA over ETT
- not a definitive aw
- lower seal pressure (can’t use higher pp)
- higher frequency of gastric insufflation
- does not maximally protect against aspiration
- no protection against laryngospasm
What is the common cause of airway obstruction during induction?
Obstruction by tongue and epiglottis due to relaxation of genioglossus muscle
(Genie cause your blue, since you’re not breathing= blue tongue= genioglossus)
What can you do to improve obstruction in airway for induction?
Cervical flexion, head extension (sniffing)
Jaw thrust
Still obstructed—> OPA/NPA
How do you measure nasal airway trumpet?
Distance from nares to meatus of ear.
Diameter French size 24-36
What is the length and angle of right bronchi?
2.5 cm long and angle of 25
What is the length and angle of left bronchi?
5 cm with an angle of 45 degrees
What are average size LMA for adult man and woman?
5LMA- man
4LMA- woman
Two types of oral
Bergman (BOA) and Guedel
Classic vs Supreme LMA
Supreme and pro seal handles PPV put o 30 cmH2o
Also has integrated bite block. Regular LMAs need additional bite block.
What are the intrinsic laryngeal muscles of glottis opening?
Lateral Cricoarytenoid
Arytenoid muscles
Posterior cricoarytenoid
Intrinsic laryngeal muscles that control vocal cord length?
Cricothyroid
Thyroarytenoid
Vocalis
When might you have good ETT placement but not have ETCO2 waveform
Severe bronchospasm
Equipment malfunction
Cardiac arrest
Hemodynamic collapse that may prevent appearance of capnogram tracing
When is mask ventilation contraindicated?
Risk regurgitation increased
SEVERE facial trauma
Pt where head and neck manipulation must be avoided.
What are basic questions to ask during airway assessment?
Radiation or burn to head/neck C-spine pain or LROM TMJ pain Rheumatoid arthritis Anklylosing spondylitis Abscess or tumor Prior intubation or tracheotomy Snoring or sleep apnea Dysphagia or stridor
