Unit 1 Respiratory Unit 4: Airway Management Flashcards
What are the classes of the Mallampati exam?
Class I: (tonsills) Pillars, Uvula, soft palate, hard palate
Class II: Uvula, soft palate, hard palate
Class III: soft palate, hard palate
Class IV: hard palate
What does the inter-incisor gap affect? Normal measurements?
The ability to align oral, pharyngeal, and laryngeal axes.
2-3 finger breadths or 4 cm
What are the 3 borders of the submandibular space?
Superior border: mental
Inferior border: hyoid bone
Lateral border: either side of neck
What test helps estimate the size of the submandibular space?
Thyromental distance
What 2 thyromental distance measurements may indicate a more difficult laryngoscopy?
Less than 6 cm - 3 fingerbreadths
Greater than 9 cm
What test assesses the function of the temporomandibular joint?
Mandibular protrusion test (upper lip bite test)
What are the classes of the mandibular protrusion test?
Class I: can move lower incisors past upper and bite vermilion of lip
Class II: can move lower incisors in line with upper
Class III: cannot move lower incisors past uppers
What test assesses the ability to place patient into a sniff position?
Atlantic-occipital join mobility
What is normal AO flexion and extension?
90-165 degrees
What is normal AO extension? What degree suggests laryngoscopy will be difficult?
35 degrees
<23 degrees
What 8 conditions impair AO mobility?
DJD Rheumatic arthritis Ankylosing spondylitis Trauma Surgical fixation Klippel-Feil Down syndrome DM (joint glycosylation)
What test grading system is used for the view obtained during direct laryngoscopy?
Cormack and Lehane score
What are the grades of the Cormack and Lehane score?
Grade I: complete or nearly complete view of glottic opening
Grade II: posterior region of the glottic opening
Grade III: epiglottis only
Grade IV: soft palate only
What is a IIA and IIB score of Cormack and Lehane?
IIA: posterior region of the glottic opening
IIB: corniculate cartilages and posterior vocal cords, no part of the opening
Risk factors for difficult mask ventilation? Mnemonic
“BONES” Beard Obese - BMI > 26 No teeth Elderly - > 55y Snoring
What are 10 risk factors for difficult laryngoscopy and endotracheal intubation?
Small mouth opening Long incisors Prominent overbite High, arched palate Mallampati class III or IV Retrognathic jaw Inability to subluxation jaw Short, thick neck Short thyromental distance Reduced cervical mobility
What are 6 risk factors for placement of a supraglottic airway/ will it work?
Limited mouth opening
Upper airway obstruction
Altered pharyngeal anatomy
Poor lung compliance - requires excessive PIP
Increased airway resistance - requires excessive PIP
Lower airway obstruction
What are 5 risk factors for difficult invasive airway placement?
Abnormal neck anatomy Obesity Short neck Laryngeal trauma Limited access to cricothyroid membrane
What are the current fasting guidelines?
2 hrs - clear liquid
4 hrs - breast milk
6 hrs - nonhuman milk, infant formula, solid food
8 hrs - fried or fatty food
What does ingestion of clear liquid 2 hours before surgery do to gastric volume and pH?
Reduces gastric volume and increases gastric pH, this reduces risk of Mendelson syndrome
What is Mendelson syndrome risk factors?
Gastric pH < 2.5
Gastric volume > 25 mL (0.4 mL/kg)
During an RSI how much pressure is applied to the cricoid ring before, and after LOC?
Before - 20 Newtons or ~ 2 kg
After - 40 Newtons or ~ 4 kg
What are 6 complications of cricoid pressure?
Airway obstruction
Difficult with laryngoscopy
Impaired glottic visualization
Difficult intubation
Reduced lower esophageal sphincter pressure
Esophageal rupture if patient is actively vomiting
List 3 causes of angioedema
Anaphylaxis
Angiotensin-converting enzyme inhibitors
Hereditary angioedema (C1 esterase deficiency)
What it the cause and treatment for anaphylaxis?
Cause - exposure to triggering agent
TX - epinephrine, antihistamines, steroids
What is the cause and treatment for angioedema caused by ACE inhibitors?
Cause - ACE inhibitor prevents bradykinin breakdown
TX - discontinue ACE
Icatibant (bradykinin receptor antagonist)
Ecallantide (plasma kallidrein inhibitor - stops conversion of kininogen to bradykinin)
FFP (contains enzymes that metabolize bradykinin)
C1 esterase concentrate
What is the cause and treatment of hereditary angioedema?
Cause: genetics (C1 esterase deficiency)
TX: C1 esterase concentrate, FFP, ecallantide, icatibant
What patients should receive prophylactic treatment for angioedema?
Those with C1 esterase deficiency for procedures requiring tracheal intubation
What is Ludwig’s Angina?
A bacterial infection characterized by rapidly progressing cellulitis in the floor of the mouth
What are the airway implications of Ludwig’s Angina?
Inflammation and edema compresses the submandibular, submaxillary, and sublingual spaces, most significant concern is posterior displacement of the tongue resulting in complete, supraglottic airway obstruction
What is the best way to secure an airway in a patient with Ludwig’s Angina?
Awake nasal intubation
Awake tracheostomy
Why is retrograde intubation contraindicated in a patient with Ludwig’s Angina?
Retrograde intubation is contraindicated in anyone with infection about the level of the trachea
What congenital conditions have large tongue?
“Big Tongue”
Beckwith syndrome
Trisomy 21
What congenital conditions have small/underdeveloped mandible? (Micrognathia)
“Please Get That Chin” Pierre Robin Goldenhar Treacher Collins Cri du Chat
What congenital conditions have cervical spine anomaly?
“Kids Try Gold”
Klippel-Feil
Trisomy 21
Goldenhar
What 3 symptoms are seen with Pierre Robin?
Small/underdeveloped mandible - micrognathia or mandibular hypoplasia
Tongue that falls back and downwards - glossoptosis
Cleft palate
Neonates often require intubation
What 4 symptoms are seen with Treacher Collins?
Small mouth
Small/underdeveloped mandible
Nasal airway is blocked by tissue - choanal atresia
Ocular and auricular anomalies
What 4 symptoms are seen with Trisomy 21?
Small mouth
Large tongue
Atlantoaxial instability
Small sub glottic diameter - subglottic stenosis
What symptoms is seen with Klippel-Feil?
Congenital fusion of cervical vertebrae
What 2 symptoms are seen with Goldenhar
Small/underdeveloped mandible
Cervical spine anomaly
What symptom is seen with Beckwith syndrome?
Large tongue
What 3 symptoms are seen with Cri du Chat?
Small/underdeveloped mandible
Laryngomalacia - congenital softening of tissues of the larynx
Stridor
The sniffing position involves what movement of the cervical vertebra and Atlanta-occipital joint?
Cervical flexion
Atlanta-occipital extension
What 3 axes does the sniff position align?
Oral
Pharyngeal
Laryngeal
What is the HELP position?
A modification of the sniff position for obese patients.
Head Elevated Laryngoscopy Position.
AKA ramping
How far can head position change the depth of the ETT?
Neck flexion and extension moves the tube ~ 2cm
Lateral rotation of the neck moves the tip of the tube away from the carina ~ 0.7 cm
What are the 4 types of oral airways?
Guedel
Berman
Williams
Ovassapian
What are the 2 specific uses of a Williams oral airway?
Blind orotracheal intubation
Fiberoptic intubation
What is the specific use for a Ovassapian oral airway?
Fiberoptic intubation
Why is a nasal airway better tolerated than oropharyngeal in a lightly anesthetized patient?
It can precipitate laryngospasm
What are 5 complications of placing a oral/nasal airway?
Laryngospasm Vomiting if gag reflex is intact Dental injury Oropharyngeal trauma Ischemia from compressing blood flow to affected areas
List 5 contraindications to a nasopharyngeal airway
Cribiform plate injury Coagulopathy Previous transsphenoidal hypophyesctomy Previous Caldwell-Luc procedure Nasal fracture
What 5 things should alert to a cribiform plate injury?
LeFort II or III fracture Basilar skull fracture CSF rhinorrhea Raccoon eyes Periorbital edema
What should cuff pressure be in an ETT?
< 25 cm H2O
What are the 2 types of cuffs? Which is the more common today?
Low-volume, high pressure cuff
High-volume, low pressure cuff: nearly all tubes today in modern practice
Which type of cuff has better protection against aspiration?
Low-volume, high pressure cuff
Which cuff’s pressure can be measured with a monometer?
High-volume, low pressure cuff
Which cuff has a lower incidence of sore throat?
Low-volume, high pressure cuff
What type of cuff is a “microthin cuff”? What are it’s benefits?
High-volume, low pressure cuff.
Lower pressure on tracheal mucosa
Better protection against liquid aspiration
What are 4 ways to minimize cuff pressure?
Use a manometer periodically during case
Fill cuff with same O2/N2O mixture
Full cuff with water or saline - provides more stable pressure but takes longer to deflate
Use ETT with Lanz pressure-regulating valve
What is the Murphy eye?
The small hole on the opposite site of an ETT from the bevel
What is the purpose of the Murphy eye?
Provides an alternative passage for air moment in case the tip becomes occluded
How do you calculate the size and depth of a pediatric ETT?
ETT size without cuff: (age / 4) + 4
ETT size with cuff: (age / 4) + 3.5
Depth: ID x 3 (size of tube x 3)