Leo- Eval of Airway Flashcards
What are the 3 unpaired larynx cartilages?
Cricoid
Thyroid
Epiglottis
What are the 3 paired larynx cartilages?
Arytenoids
Cuneiforms
Corniculate
What is the function of the PosteriorCricoArytenoids muscle?
Pull Cords apart (PCA) ***
Cricothyroid
Lengthen and stretch
VOCALIS (vocal ligament)
part of muscle that help with voice
Larynx all nerves come from
Vagus
***Most of motor function comes from the
Recurrent LARYNGEAL nerve
➢ Difficult mask ventilation
“Not possible for the unassisted anesthesiologist to prevent or reverse signs of inadequate ventilation during positive pressure mask ventilation
➢Difficult intubation
The proper insertion of an endotracheal tube using conventional laryngoscopy requires more than 3 attempts, or greater than 10 minutes”
➢Failed airway is defined as
⚫ 3 failed attempts at orotracheal intubation by a skilled provider
⚫ Failure to maintain acceptable saturations (> 90%) in otherwise normal individuals
ASA Closed Claims Database: single most important factor leading to fail airway
“Failure to evaluate the airway and predict difficulty is the single most important factor leading to a failed airway”
Incidence of Difficult Intubation by Rigid Laryngoscopy
⚫ Failed intubation 1 in 280
➢ Parturient 2.7%
Parturient and intubation
Almost 10x greater than in the nonparturient patient
➢ Major cause of injury in anesthetic practice
➢ Inadequate ventilation—largest class of adverse events
_____is especially important in patients at high risk for aspiration
Anticipation
Factors preventing a snug mask fit,
interfering with positioning of head and neck, limited opening of mouth, and narrow or distorted airway
Difficult Intubation Predictors:➢ External anatomic features
- ↓ Head/neck movement (atlanto-occipital joint)
- Jaw movement (temporo-mandibular joint), mouth opening, and subluxation of the mandible
- Receding mandible
- Protruding maxillary incisors
- Obesity
More Predictors o difficult airway
Thyromental distance <6cm or 3 fingerbreaths.
• Sternomental distance
• Visualization of the oropharyngeal structures
• Anterior tilt of the larynx
• Radiographic assessment
Mouth opening (distance between incisors) limited to
3.5 cm or less will contribute to difficult intubation
Mouth opening is limited by
Limited by: ⚫ TMJ dysfunction ⚫ Congenital or surgical fusion of the joints/ vertebrae ⚫ Trauma ⚫ Tissue contracture around the mouth ⚫ Trismus (lock jaw)
Protruding maxillary incisors can interfere with
laryngoscope placement and ETT passage
Mouth opened maximally normal
normal opening 5-6cm
➢ Class II–
base of tongue obscures tonsillar pillars, posterior pharyngeal wall visible below soft palate, uvula
➢ Class III–
only soft palate visualized (7.58 x greater chance of difficult intubation than class I)
➢ Class IV–
essentially nothing visualized, not even soft palate (11.2x greater chance of difficult intubation than class I)
Don’t Forget . . .
➢ Overbite
➢ Mobility of and ability to displace mandible
– can patient push jaw to place lower teeth
past the top teeth
⚫ May not be able to pull mandible forward far
enough to see larynx - TMJ
➢ Tongue Size
➢ Loose, chipped, or missing teeth, or dental
work
Micrognatia
No room to displace the tongue and epiglottis forward
➢ Anterior airway associated wtih ______
Micrognatia ; with the laryngoscope, the structures will be anterior to your field of view
Neck ➢ Limited Mobility -
Neck touch chin to chest, both shoulders, and extend back (normal 55 degrees) Harder to push tongue and epiglottis forward
➢ Neck circumference
> 27 inches is suggestive of difficult management
Neck: With trachea check
➢ Trachea mobility and alignment
➢ TM Less than
3 fingerbreadths is considered a receding mandible and may contribute to difficulty with intubation
➢ Rigid laryngoscopy may be impossible if
<6cm
➢ TM Measured with the
head fully extended,
between the bony part of the mentum of
the mandible and the thyroid notch
➢ TM Measured with the
head fully extended, between the bony part of the mentum of the mandible and the thyroid notch
Atlanto-occipital Mobility
Alignment of the oral, pharyngeal, and laryngeal axis required for visualization of the glottis during rigid laryngoscopy
Head has to be above the
Breast
What is responsible for the sensory and motor innervation of the larynx?
The vagus nerve (cranial nerve X), via the superior and recurrent laryngeal nerve, is
Has the highest density of touch receptors
The posterior half of the vocal cords
During bedside evaluation of Atlanto occipital mobility?
Bedside evaluation: have the patient sit straight and extend their head while maintaining a neutral cervical spine
With Atlanto occipital mobility ↓ degree of head extension indicate→
↑ possibility
for difficult intubation
Axis alignment
Elevation of the head about 10 cm with pads below to occiput with the shoulders remaining on the table aligns the laryngeal and pharyngeal axis
Head extension at the atlanto-occipital joint
serves to
create the shortest distance and most nearly straight line from the incisor teeth to glottic opening
Difficult bag-mask-ventilation: MOANS
➢ M: Mask seal ➢ O: Obese ➢ A: Aged ➢ N: No teeth ➢ S: Snores or stif
Difficult laryngoscopy and intubation: LEMON
L: Look externally ➢ E: Evaluate 3-3 (3 fingers between teeth, 3 fingers chin-neck to thyroid notch) ➢ M: Mallampati class ➢ O: Obstruction ➢ N: Neck mobility
Radiography: Not routine but To confirm vertebral damage and reveal degree of airway compression
⚫ Lateral C spine
⚫ MRI
⚫ CT
Predictors of a Difficult Airway
➢ High Mallampati Classification ➢ Small mouth opening ➢ Prominent Incisors ➢ Thyromental Distance <6 cm ➢ Decreased neck extension ➢ Neck Circumference
Predictors of Difficult FACE MASK VENTILATION
ABBSMLL
➢ Age >55 y.o. ➢ BMI >26-30 kg/m2 ➢ Beard ➢ Snoring ➢ Lack of teeth ➢ Mallampati III or IV ➢ Limited mandibular protrusion
Single most important predictor for both Difficult mask
ventilation and difficult intubation
Limited mandibular protrusion
Predictors of Impossible Face Mask Ventilation
➢ Male ➢ Beard ➢ Obstructive Sleep Apnea ➢ Mallampatie III or IV ➢ Neck radiation changes
Many of the airway tests such as Mallampati and thyromental distance have limitations
Interobserver variability, low to modest sensitivity, inability to assess for base of tongue pathology
Categories of Difficult Airway
➢ Known or expected difficult airway
➢ Probable difficult airway
➢ Unexpected difficult airway
Mouth opening & proper position of the
Head & Neck adversely affected by:
➢ Tissues of head/neck, oral cavity, pharynx, & larynx fixed by tumor, surgical scars, or radiation fibrosis
➢ Supra-epiglottic mass may limit mobility of Epiglottis → complete airway obstruction after induction
➢ Rheumatoid arthritis→ pathologic changes
➢ May involve any joint
⚫ Cervical spine
⚫ Temporomandibular joint
⚫ Cricoarytenoid joint
➢ may indicate laryngeal involvement
Change in voice, dysphasia, dysarthria, stridor,
or sense of fullness in oropharynx
Progressive cervical spondylosis (degeneration) can lead to
severe flexion deformity
Should be the technique of choice if there is any reason to believe that maintaining a patent airway after induction of
anesthesia may be difficult
Awake intubation
______________ in patients with an unstable neck should be done with extreme caution.
➢ Avoid movement that can cause spinal
cord compression and damage
Tracheal intubation
Awake fiberoptic intubation can be performed without
➢ Any head and neck stabilizing device can be left in place to prevent movement of c-spin
atlanto-occipital extension
Predictors of difficult video laryngoscopy
Scarring ➢ Radiation ➢ Masses ➢ Large neck circumference ➢ TMD < 6 cm ➢ Limited neck mobility ➢ Operator experience
➢ Airway assessment should be performed with
the patien
in a sitting position as well as supine.
➢ Respiratory function and airway patency can be
greatly changed with
position changes.
What may interfere with spontaneous respirations?
➢ Chest compliance and vital capacity change
➢ Even with local or regional anesthesia, work of
breathing may be
Excessive and require ventilatory support
For mobid Obesity create an Create an angle where the
____
Why? •
head and neck are above the thorax, so gravity will pull the weight away from airway
helps view and gives room for laryngoscope handle
The higher incidence of (3 conditions) found in obese
patients, place these patients at a higher risk for aspiration of gastric contents
hiatal hernia
low gastric pH ( < 2.5),
low FRC
For obese patient, to minimize the risk of
aspiration, what is performed?
a RSI is commonly performed
Safe and logical approach for morbid obese patients?
Securing the airway in morbidly obese patients before induction of anesthesia
2 studies show no correlation between
obesity and difficult intubation
Morbid Obesity Weight distribution and consideration
Abdomen & hip area less important than if weight is
also in upper body;
Fat in upper body lead to Cervical spine fat pads interfere with
laryngoscopy
Rapid desaturation during apnea 2o to
↓ FRC limits time for intubation
➢ Life threatening infection
Epiglottitis
Epiglottis is what kind of infection?
Bacterial
➢ Lasts 2-4 days
Epiglottis onset and progression
➢ Rapid onset and progression→ urgent dx and tx
4 Ds of Epiglottis
Dysphagia, dysphonia, dyspnea, drooling
S & S of airway injury
Subcutaneous emphysema
Hoarseness
Stridor,
Tracheal deviation
Trauma Patient
Examine for
➢ Examine for cervical spine injuries
⚫ Cervical collar & axial traction during intubation
⚫ Limited range of motion
Congenital Syndromes most often accompanied by aberrations of the upper airway (4)
⚫ Crouzon’s
⚫ Goldenhar’s
⚫ Pierre Robin’s
⚫ Treacher Collins
Congenital syndromes: These children may also have a shortened trachea and should have
ETT positioned fiberoptically
Crucial to assess
mouth size and opening, size of tongue, and neck movement, as well as feeling the neck under the mandible
Intrathoracic Lesions
➢ IT lesions can compromise the airway through
compression of the tracheobronchial tree or by invasion of the trachea or bronchi
➢ Anterior mediastinal tumors can completely
block the airway when a patient is placed in a
supine position
➢ If flow-volume loop deterioration occurs in the
supine position,
the patient should not be anesthetized or paralyzed
Cormack-Lehane laryngeal grading system
➢ View during direct laryngoscopy
➢ III
III—epiglottis
Cormack-Lehane laryngeal grading system
➢ View during direct laryngoscopy
➢ I—
entire glottic opening
Cormack-Lehane laryngeal grading system
➢ View during direct laryngoscop II—
posterior glottic structures
Cormack-Lehane laryngeal grading system
➢ View during direct laryngoscopy➢ IV
soft palate only
Anteriorly Tilted Larynx
➢ Degree of thyroid cartilage tilt can be
related to
➢
difficulty of laryngeal exposure
w/ Mac blade
Anteriorly Tilted Larynx Reduced exposure
by depression of the thyroid cartilage
Anteriorly Tilted Larynx Increased exposure by
cricoid pressure
Unexpected Difficult Airway
Hyperplasia of the lingual tonsils, a lingual thyroid nodule/cyst, and an asymptomatic epiglottic cyst can contribute to a failed intubation or ventilation.
Anatomical Features Associated with unanticipated Difficult Intubations
Anterior larynx (most common) ➢ Abnormal neck anatomy (poor mobility, short) ➢ Decreased mouth opening
The KEY to successful awake intubation
Topical anesthesia
Most conservative approach when difficult airway is
known or suspected
Awake intubation
During awake intubation, Important to use
glycopyrrolate to dry mucous membranes prior to topical LA (at least 20 min before)
When deciding on awake vs. asleep airway management:
➢ If difficulty w/ ventilation by both mask &
supraglottic airway device is anticipated.
➢ Consider presence of at least 3 factors
predictive of difficult or impossible to mask
ventilate
Preexisting Airways
➢ Endotracheal or tracheal ➢ Indication ➢ Date of Placement ➢ Ease of Placement ➢ Size ➢ Presence of cuff ➢ Vent settings ➢ Recent ABG
Difficult intubation is a
life-threatening situation
➢ Even the most experience provider seeks
help
Unexpected failed intubation/ventilation may be
due to
Supraglottic mass or lingual tonsillar
hyperplasia
Incidence of tracheal stenosis after emergency
tracheostomy is
high (FO evaluation prior to intubation is suggested)
When in doubt, secure airway with the patient
awake and spontaneously breathing
are the major airway management problems in
pediatrics
Infection related and congenital airway compromise
➢ In adults, stridor at rest=
serious obstruction w/ cross sectional opening less than 4mm
Should always be available
➢ Emergency airway management cart
➢ Important for pt w/ difficult airway to get
MedicAlert bracelet (make sure to document on record)
