Airway Evaluation Flashcards
What are two major risk factors for a difficult airway?
Morbid obesity
Obstructive sleep apnea
What type of position should we place the patient in prior to intubation?
Sniffing position
Describe the importance of the Atlanta-occipital joint mobility?
Successful exposure of glottis during direct laryngoscopy requires aligning the oral, pharyngeal and laryngeal axis
Elevating the patient’s head with a pillow aligns what two axes?
Pharyngeal and laryngeal
What is the purpose of extending the head prior to intubation?
To create the shortest distance and most nearly straight line from the incisor teeth to the glottic opening
What are the three axes of the larynx?
Oral
Pharyngeal
Laryngeal
What is the normal amount of head extension required for optimal view?
normal extension is 35 degrees
What Atlanto-occipital joint extension is associated with a grade III or IV view?
a greater than two-thrds decrease from normal
What does temporo-mandibular mobility measure?
How widely can the patient open his/her mouth
How is temper-mandibular mobility measured?
Distance between incisors in adults with mouth fully opened
What is the typical distance of a fully opened mouth of an adult?
30-40mm (3 large finger-breaths)
What is another method of assessing the temper-mandibular mobility other than mouth opening?
The ability to protrude the mandible
What is the positive predictive value of Mallampati classification when used alone?
Positive predictive value 20% when used alone
What is the premise of the Mallampati classification system?
Based on the assumption that when the base of the tongue is disproportionately large, the tongue overshadows the larynx, resulting in difficult exposure of the larynx during DVL
What is a disadvantage to the Mallampati classification system?
Subject to inter-observer variability
How should the Mallampati test be performed?
The patient is sitting up in a neutral position, open mouth as wide as they can, extrude tongue with no phonation
What can nullify a Mallampati test?
Phonation gives false data
How are Mallampati tests classified?
Class I: P-pillars, uvula, soft palate, hard palate
Class II: U- uvula, soft palate, hard palate
Class III: S- soft palate, hard palate
Class IV:H-hard palate only
What can mandibular movement determine?
Indicates the available space for the tongue to be displaced anteriorly during DVL
How do we measure the Thyromental distance?
Distance from the notch of the thyroid cartilage to the tip of the mentum
What thyromental distance may indicate difficulty achieving cord visualization?
Distance less than 6cm (3 finger breaths)
How does the provider check the thyromental distance?
Ask the patient to fully extend their head and close their mouth
What problem does a short thyromental distance create?
Creates difficulty in aligning pharyngeal and laryngeal axes
Where is the sternomental distance measured?
Distance between the sternal notch and mentum
What sternomental distance is associated with difficult intubation?
Distance less than 13.5cm
What dental issues may interfere with achieving optimal laryngoscopes view?
Prominent maxillary incisors or overbite
What grading system is used to classify what is seen on a DVL?
Cormac Lagane grading scale
What is seen on a Grade I view on the Cormac Lagane grading scale?
Full view of glottic opening
What is seen on a Grade II view on the Cormac Lagane grading scale?
Posterior portion of glottic opening and arytenoid cartilage is visible
What is seen on a Grade III view on the Cormac Lagane grading scale?
Only tip of epiglottis is visible
What is seen on a Grade IV view on the Cormac Lagane grading scale?
Soft palate visible, no recognizable laryngeal structures
What causes a laryngospasm?
Direct glottic or supraglottic stimulation including secretions, foreign bodies, inhaled agents and other noxious stimuli
What steps should be taken to treat a laryngospasm?
Remove the stimulus
CPAP for mild, incomplete glottic closure
Deepen anesthetic
Muscle relaxants (intubation if serious)
How much Sucs is required to break a laryngospasm?
10-20mg
What is the purpose of coughing?
Expels secretions and foreign bodies from lower respiratory tract
What are characteristics of a partial obstruction?
Diminished tidal volume
Retraction of upper chest
Snoring sound heard
Inspiratory stridor
What are characteristics of a complete obstruction?
Lack of air movement or breath sounds
Diaphragmatic tugging, paradoxical movements
How can soft tissue obstructions be treated?
Head-tilt, chin-lift maneuver or by jaw thrust (moves hyoid bone anteriorly and lifts epiglottis)
How do oropharyngeal and nasopharyngeal function?
Provides an artificial passage behind the tongue
