Airway assessment Flashcards
What are the 5 MAIN parts of the airway anatomy?
Nose
Mouth
Pharynx
Larynx
Trachea
Explain the nasal anatomy:
- External nose
- Internal nasal cavity
- divided by the septum
- cribriform plate
- turbinates
The lateral wall of the nasal passages is characterized by the presence of what?
3 turbinates or conchae that divide the nasal passage into 3 scroll-shaped meatuses
Which nasal meatus is the preferred pathway for passage of nasal airway devices?
Inferior meatus
Between the inferior turbinate and the floor of the nasal cavity
What are the 3 different turbinates?
Inferior
Middle
Superior
What is a turbinate? What is a special consideration for these?
Filters for sinuses
These are very vascular, so this is what bleeds during nasal procedures!
What is the job of the septum?
What is a special consideration?
Divides the nasal cavity
It is also very vascular, so you can poke a hole through it!
What can you give to prevent trauma in the nose?
Vasoconstrictors
What are examples of vasoconstrictors we can use in the nose? What was the first one?
Cocaine soaked in gauze and shoved up the nose was the 1st!
Phenylephrine: does have hemodynamic effects
Oxymetazoline: no hemodynamic effects
Use lidocaine jelly with nasal airways
The _____ , formed by parts of the maxilla and the palatine bones, makes up the anterior ______ of the roof of the mouth
Hard palate
2/3
What makes up the roof of the mouth?
Maxilla and palatine bones
Hard palate
Soft palate
Teeth
What makes up the floor of the mouth?
Tongue
Mandible
Teeth
If the tongue is dry, it acts like ____. What can you use if so?
Velcro
KY
What is one of the primary causes of upper airway obstruction during anesthesia?
Loss of pharyngeal muscle tone
What can you do to counteract the tendency of the pharyngeal airway to collapse?
Chin lift with mouth closure
This increases longitudinal tension in the pharyngeal muscles
Where does the nasopharynx end?
What is the region called?
Soft palate
Velopharynx
Where is a common site of airway obstruction in both awake and anesthetized pts?
Velopharynx
Where does the pharynx start and finish? What does it join together?
Muscular tube from the base of the skull to the lower border of the cricoid cartilage
Joins the nasal and oral cavities with larynx and esophagus
What are the 3 parts of the pharynx?
Nasopharynx
Oropharynx
Hypopharynx
What is the region of the oropharynx?
Soft palate to epiglottis
What is the region of the hypopharynx?
Epiglottis to cricoid cartilage
Where does the larynx start and finish? What is it an inlet to?
Epiglottis to lower end of cricoid cartilage
Trachea
The larynx is suspended from the hyoid bone by the ________
Thyrohyoid membrane
Pts who get larynx removals are increased risk for aspiration because of what?
Loss of epiglottis
Where are your vocal cords?
Larynx
Attached to the arytenoids and the thyroid notch on thyroid cartilage
What are the 2 classifications of laryngeal cartilages and their subsets?
Unpaired
- thyroid
- cricoid
- epliglottis
Paired
- Arytenoid
- Corniculate
- Cuneiform
What is the only complete cartilage ring in the trachea?
Cricoid
______ is the largest of the laryngeal cartilages and supports most of the soft tissues
Thyroid cartilage
How can you get to the cricothyroid membrane via palpation?
Under mandible, you can feel hyoid bone right underneath it, below that, there is tissue gap, then you come down and there is the adam’s apple (laryngeal prominence), then you get to cricothyroid membrane (indentation below prominence)
Where does the trachea extend from and to?
Extends from the inferior cricoid membrane to carina
What is the average length of the adult trachea?
10 to 15 cm
What shape is the trachea? Will you be able to see it on ultrasound?
C shaped
Yes!
Where is the trachea closed and what is it closed by?
Posteriorly by the longitudinal trachealis muscle
Where is the trachea bound, and by what?
Anteriorly bound by tracheal rings
What are the 2 basic questions we ask first when doing airway assessment?
Which is more important?
Can I intubate?
Can I ventilate?
Ventilation is more important!
What is more valuable than any airway “test”?
History
Specifically difficult airway
What is a common sign of a previous difficult airway?
Pt reported sore throat
If the pt woke up and their jaw was sore, what is this due to?
Jaw thrusting
What are the common history concerns?
- Past difficult intubation (most predictive factor)
- Report of excessive sore throat
- Report of cut lip/broken tooth
- Recent onset of hoarseness
- History of OSA
- Lesions intra-orally (base of tongue, lingual tonsils)
What does STOP-BANG stand for?
S = snoring?
T = tired?
O = observed apnea?
P= high blood pressure?
B = BMI > 35?
A = Age >50?
N = Neck circumference > 40 cm (16 inch)
G = Gender is male?
Hoarseness after intubation could be due to what?
Subglottic stenosis and then using the wrong size ETT
Increasing air in the cuff can worsen stenosis
What are the “difficult” forms that may be seen?
Difficult mask ventilation
Difficult laryngoscopy
Difficult intubation
Failed intubation
What does the airway eval include?
- Visual inspection of the face and neck
- Assessment of mouth opening
- Evaluation of oropharyngeal anatomy and dentition
- Assessment of neck range of motion (sniffing position)
- Assessment of the submandibular space
- Assessment of the pt’s ability to slide the mandible anteriorly
Where is the submandibular space?
In between the thyroid and mandible
What is bulldog jaws?
Jaw sticks out
Good sign you can get them intubated!
What is recess jaw? Another name for this?
Mandibular retrognathia
A facial bone deformity where the lower jaw is positioned behind the upper jaw
What are key points to look for during visual inspection?
- Facial deformities
- Head and neck cancers
- Burns
- Goiters
- Short or thick neck
- Receding mandible
- Beards
- C-collars
What width of neck is considered a difficult intubation?
Is this type of measurement more or less predictive than BMI?
> 43 cm
More
What is the concern with facial hair?
Difficult to ventilate with mask because there might be an air leak
What is the concern with goiters?
Goiters may compress the airway when you give paralytics because neck muscles are no longer elevating it - may have to intubate awake
What is the preferred mouth opening distance? What is this also known as?
Inter-incisor distance
> 6 cm (3 finger breadths)
What are some possible pathologic characteristics of the oropharynx?
Tumors
Palate deformities
- high arched palate
- cleft palate
Macroglossia
What is something that could cause a big tongue?
How can you treat this?
Ace inhibitors
Treat with vasoconstrictors and antihistamines; can also use FFP or TXA
What are the parts of a dental assessment?
- long upper incisors
- poor dentition/loose teeth
- cosmetic work
- edentulousness
Why do we worry about pts with “buck teeth”?
You can knock them out!
When you mask ventilate, what provides structure to keep the airway open?
Teeth
What percent of closed insurance claims against anesthesia providers are due to dental injury?
What percent occurs during tracheal intubation?
25%
75%
What are some things that can cause dental injuries?
Laryngoscope blades
Rigid suction catheters
Oropharyngeal airway placement
Biting down on ETT/LMA/airways during emergence
What are the most frequently injured teeth during endotracheal intubation?
Anterior axillary central and lateral incisors
Where can a hidden oral or dental pathology be found that is usually not detected during preop?
Maxillary central incisors (two front upper teeth)
When does knocking the teeth out occur the most?
What can you do to prevent this?
Scissoring
If you have to scissor, do it on the molars
Do the teeth get knocked out on the left or right side usually?
Left
We tend to shove everything to the left in the airway
Describe sniffing position
Cervical flexion and atlanto-occipital extension
- tilt the head back and extend neck while lifting head a little
Aligns oral, pharyngeal, and laryngeal axis
When doing laryngoscopy, where do you want the ear?
Level with the chest with neck with good neck extension
What is the sternomental distance?
What is the preferred distance?
Distance between the sternal notch and chin with head in full extension/mouth closed
> 12.5 cm
What are you looking at when assessing thyromental distance?
What is the preferred distance?
Submandibular compliance (tip of the chin to thyroid notch)
> 6.5 cm (3 finger breadths)
What is the prognathic ability?
Which test between the 2 best measures prognathic ability?
Extension of lower incisors beyond upper incisors OR upper lip bit test (lower incisors bite the upper lip)
Upper lip bite test
What is the mallampati test?
What are the classes?
Visibility of oropharyngeal structures
Class I-IV
Describe the process of the mallampati test
- Patient is seated upright with head neutral
- Mouth open
- Tongue protruded
- No phonation
Describe mallampati class I
Fauces, pillars, entire uvula, and soft palate are visible
- Arched opening at the back of the mouth leading to the pharynx
Describe mallampati class II
Fauces, portion of the uvula, and soft palate visible
Describe mallampati class III
Base of the uvula and soft palate visible
Describe mallampati class IV
Only hard palate visible
What are two manuevers we can use to help with laryngeal manipulation?
BURP
OELM (optimal external laryngeal manipulation)
Describe the BURP maneuver
Apply pressure backwards (towards esophagus) and upward and toward the right – can do this to manipulate airway but you need to do it then someone can hold it there
Describe OELM
Essentially the same thing as BURP
What is the Cormack-lehane classification?
What are the grades?
Classification of laryngeal view
Grades I-IV
What is the difference between mallampati and cormack-lehane?
Mallampati is an external airway eval
Cormack is an internal airway eval
Describe CL-grade 1:
Entire glottis is visible
Describe CL-grade 2:
Only the posterior portion of the glottis visible
Describe CL-grade 3:
No part of the glottis and only epiglottis visible
Describe CL-grade 4:
Epiglottis cannot be seen
Pediatric airways do not have ______ vocal cords so everything looks ______
Lighter colored
Pink
CL statistics chart:
Helpful to use this chart when documenting to let the next person know
Criteria associated with difficult mask ventilation:
O: Obesity
- BMI > 30 kg/m2
B: Beard
E: Edentulous (no teeth)
S: Snorer, OSA
E: Elderly, male
- Age > 55
If you have at least 2 of these criteria, they will almost always be mallampati 3 or 4
Predicting the difficult airway using “BOOTS” acronym:
- Beard – gel
- Obesity
- Older
- Toothless – “gather” cheek, 2 people
- Sounds – snoring, stridor
- Inability to maintain O2 saturations >90% with BMV
Predicting intubation using “LEMON” acronym:
L- Look – abnormal face, existing trauma, unusual anatomy
Evaluate – 3-3-2 rule (3 finger mouth opening, 3 fingers along the floor of the mandible, 2 fingers between the space between the superior notch of the thyroid cartilage and neck/mandible junction
Mallampati score – I-IV, relates mouth opening to size of tongue
Obstruction/obesity – tumor, infection
Neck mobility
Criteria associated with difficult airway:
- Large upper incisors
- Strong overbite
- Inability to protrude mandible
- Small inter-incisor distance (<6cm)
- Mallampati 3 or 4
- Large tongue
- Narrow or high arched palate
- Short thyromental distance (<6.5 cm)
- Excessive mandibular soft tissue
- Short, thick neck
- Decreased cervical range of motion
ASA difficult airway algorithm
In the difficult airway algorithm, what does the red emphasize?
The pace of these difficult airway decisions are important
If you have trouble intubated, try:
supraglottic airway or reposition patient to try to reintubate
What is included in the pre-intubation section of the difficult airway algorithm?
Choosing between awake or post induction airway strategy
- Suspected difficult laryngoscopy
- Suspected difficult ventilation with face mask/supraglottic airway
- Significant increased risk of aspiration
- Increased risk of rapid desaturation
- Suspected difficult emergency invasive airway– this would be patients with goiters b/c hard to cut hole there
With difficult ventilation/intubation, there is significant danger of anoxic brain injury within _____
Minutes
What is one of the most important things to do if you are having difficulty intubating or ventilating?
Call for help!
Consideration if we continue to have difficulty intubating/ventilating
Limit attempts and consider awakening the pt
What is considered a dynamic airway?
Bullets (neck trauma)
Bites (anaphylaxis/angioedema)
Burns (thermal and caustic airway injuries)
Airway considerations when deciding to intubate:
mouth and neck infections, tumors, foreign bodies, bleeds
- exam: stridor, phonation, swallowing, secretions, dyspnea
Breathing considerations when deciding to intubate?
failure of oxygenation or ventilation
- often amenable to medical and non-invasive therapies – think NIV
Circulation considerations when deciding to intubate:
supporting tissue oxygen delivery by unloading the muscles of respiration
- sepsis
Disability considerations when deciding to intubate:
CNS catastrophes and CNS depression, ongoing seizures, weakness
- exam:
1. assess ability to swallow and handle secretions (pooling, drooling, gurgling)
2. for neuromuscular weakness: FVC < 12 ml/kg and NIF < 20 cm H20
3. vomiting in the obtunded patient is a particular concern
“Feral” considerations when deciding to intubate:
need for prompt, aggressive sedation to protect patient/others
- especially with potential or undiagnosed medical instability
When trying to assess whether or not to do RSI or awake intubation, what do you do?
assess the urgency, difficult airway features, and vomiting risk
Examples of different urgencies when considering RSI vs awake
RSI: peri arrest; dynamic airway already deteriorating
Awake: stable GI bleed requiring endoscopy
slowly progressive neuromuscular weakness requiring transfer
Examples of different difficult airway features when considering RSI vs awake
RSI: known easy airway normal anatomy
Awake: fixed flexion deformity of the neck cannot open mouth
Examples of different vomiting risks when considering RSI vs awake
RSI: upper GI bleed
bowel obstruction vomiting in ED
Awake technique chart:
Local anesthetics include:
Drying agent→ glyco.
Numbing agents:
- nebulize (Nebulizer 4% lido)
- atomize
- topicalize
IV sedation includes:
Ketamine
Versed
Precedex
Fentanyl
Difficult airway flow chart:
During laaryngoscopy, where does the assistant pull?
Pulls right mouth corner
Laryngoscopy procedure in steps:
- ear to sternal notch
- equipment ready
- right mouth corner pulled
- find the epiglottis
- optimize the head
- seat the blade (sweep lips)
- optimize the larynx
A bougie acts as an _____. You can feel the _____ with the curved coude tip
Introducer
Trachea rings
If you are having a hard time ventilating with a face mask, what can you use?
LMA
High doses of opiods cause:
Rigid chest
Can’t ventilate appropriately
Drugs we give now during induction:
- fentanyl, lidocaine to blunt pain from propofol admin instead of blocking sympathetic stimulation
- We use same induction agents: etomidate, ketamine, propofol
- Can also use versed; if outside US, you can use thiopental
- Etomidate – causes adrenal suppression; lowers seizure threshhold
- Ketamine – do not give in tachycardia or hypertensive or bad CV issues
- Versed helpful with seizures; but can make delirium worse
Problems with succs:
PS this card sucks and it’s super long
- rhabdomyolysis
- existing hyperkalemia
- multiple sclerosis ALS
- muscular dystrophies / inherited myopathies
-denervating injuries > 72 hours old (e.g. stroke, spinal cord injury) - burns > 72 hours old
- crush injury > 72 hours old
- tetanus, botulism, and other exotoxin infections
- severe infections >72 hours old (esp. intra-abdominal infections) - immobilization (including patients found down)
- predisposition to malignant hyperthermia
- bradycardia
- fasciculations – increased ICP, myalgias, hastened desaturation
- masseter spasm
Contraindications to roc:
Very few!
Basically just allergies
For roc, as you ____ the dose, the onset time ______
Increase
Decreases
How long does it take succs to wear off?
5-10 minutes
How long does it take roc to wear off?
30-90 minutes
Intubation should NOT be the ______
cause of death
Physiologic “killers” during intubation:
Hypotension
Hypoxemia
Metabolic acidosis
What can you do to prevent hypotension or treat it if needed?
- At least 2 proximal peripheral IVs (PIVs)
- If unable to get PIVs, IO can be used as well for RSI
- Judicious bolus of IVF wide open or vasopressor support
- Shoot for a higher than normal BP before intubating if possible (SBP ≥140mmHg)
What does it mean to adjust doses of induction agents/paralytics to pre-RSI physiology?
Reducing the dose of your induction agent and increasing the dose of your paralytic agent for several reasons:
- Ketamine should be the induction agent of choice in shock patients (Gives simultaneous sympathetic surge and pain control).
- Rocuronium should be the paralytic agent of choice.
Why do paralytics take longer to work in shock state?
They are cardiac output dependent
What are examples of induction agents that will decrease sympathetic tone?
Benzos
Propofol
Dosing of roc:
1.6 mg/kg IV
I know this wasn’t what we were taught, it’s just what he has in slide 70
Dosing of succs:
2 mg/kg IV
Push dose pressors include:
Epinephrine
Phenylephrine
Vasopressin
What is the push dose pressor of choice? Why?
Epi
It possesses, both an alpha and beta agonist, as this not only increases vascular resistance and blood pressure, but through its beta agonist effect also increases cardiac output.
** See slide 71, he also has Neo is pressor of choice so I really don’t know ◡̈ **
MOA of phenylephrine
a pure alpha agonist (i.e. potent vasoconstrictor) increases vascular resistance and blood pressure, but will decrease cardiac output and venous return due to the lack of effect at the beta receptors
Dosing of push dose epi:
Usually 1mg/1ml
Can dilute in 10 ml syringe
Dose of push dose phenylephrine:
Vial: 10 mcg/ml
Normal doe: 50-100 mcg
Can take 10 mg and put it in 100 ml bag: this gives you 100 mcg/1ml
OR can put 10 mg in 250 ml bag for 40 mcg/1ml
Dosing of push dose vaso:
Vial: 20 units in vial
Dilute 20 units in 20 ml: pushing 1 unit per 1 ml
When trying to intubate and trying to prevent oxygenation issues, what can you do?
Use NC/NRB or both
Use a peep valve
Look for other things causing hypoxia: biggest cause is a PE
Intervention number 1 for hypoxia:
NC 15LPM + BVM 15LPM + PEEP Valve 5 – 15cmH20
- You don’t need to bag these patients, they need a tight seal and jaw thrus
In critically ill patients in which you cannot get O2 Sats ≥95%, consider shunt physiology and use Apneic CPAP Recruitment
Intervention two for hypoxia:
DSI (delayed sequence intubation)
- Give 1mg/kg IV Ketamine -> Preoxygenate -> Paralyze the Patient -> Apneic Oxygenation -> Intubate
- Used for the uncooperative or combative patient
- Procedural sedation for preoxygenation
- Ketamine 0.5-1mg/kg
Intervention 3 for hypoxia:
BUHE (back up, head elevated)
- If they can breathe there, let them keep at it. Don’t insist on laying everyone supine
Consider a short trial of ____ while you try to correct a cause of acidosis
NIPPV
Intubating _____ patients can kill them
acidotic
Intervention one for acidosis:
- Tenuous at Best-Bicarbonate->CO2
- Already tachypneic-increased CO2 makes this even worse
- Increased circulating CO2 could worsen acidosis Leading to arrhythmias
Intervention 2 for acidosis:
VAPOX (ventilator assisted pre-oxygenation)
Even a brief apneic period can worsen acidosis
Nasal Cannula at 15LPM
SIMV+PSV
- VT 8ml/kg Predicted Body Weight
- FiO2 100%
- Pressure Support 5-10cmH20
- PEEP-5
- Decrease flow rate to avoid stomach insufflation but meet needs of minute ventilation
T/F
If in cervical only suspected injury, you can still take c-collar off and stabilize neck to get better visualization
True!
someone else can hold c-spine from the front - just hold head still so you can intubate quickly
What situations are considered high aspiration risk?
upper GI bleeding
bowel obstruction
pre-induction vomiting
What can you do for high aspiration risk during induction?
NGT prior to intubation!
Intubate in semi-upright position
Bag early, but slightly less early
Initiate rescue maneuvers, such as _____ and ____ early to allow for enough reserve
Ventilation
Cricothyrotomy
Use a ______ to keep you focused on what’s important during intubation
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