Airway assessment Dr. Tushar
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Transcript of Airway assessment Dr. Tushar
Airway Assessment
Dr. TUSHAR KUMAR,DA
Anaesthesiology and critical care
Airway
Anatomically, airway is the passage through which the air/gas passes during respiration.
It may be divided into:Upper airway, andLower airway
Upper airway
Upper airway comprises of the mouth/oral cavity, nasal cavity, pharynx, nasopharynx, oropharynx, and the larynx.
MOUTH/ORAL CAVITY: Extends from the mouth opening to anterior tonsillar pillars. Includes lips, cheeks, teeth n the tongue.
NASAL CAVITY: Extends from naris to the end of the turbinates.
Upper Airway
Upper Airway
Lower airway
Lower airway includes trachea, bronchi n bronchioles, which after multiple divisions finally terminate into alveoli.
TRACHEA : Trachea extends from lower border of cricoid cartilage (C₆) to its division into 2 main bronchi (T₄).
It is 11 – 13 cm long.
Lower Airway
DEFINITION OF DIFFICULT AIRWAY(A.S.A. 1993)
A Difficult Airway is defined as the “clinical situation in which a conventionally trained anesthesiologist experiences difficulty with mask ventilation, difficulty with tracheal intubation or both”.
Airway Difficulties
Difficult to mask ventilate : 0.1 -5 % prevalence
Difficult laryngoscopy
Difficult to intubate: 1 – 2% normal surgical population. 50% of rheumatic cervical disease
Difficult LMA: 0.1 -5 % prevalence
Why airway assessment…..
Optimal patient preparation
Proper selection of equipment and technique, and
Participation of personnel experienced in the difficult airway management
How do you assess?
Difficult airway can be assessed by:
Individual indices
Group indices (with or without scoring)
Mask ventilation precedes laryngoscopy , which in turn followed by intubation.
So the assessment should be in following manner
What to assess ? ( components of the airway examination)I. Nostril patencyII. Length of upper incisor and alignmentIII. Condition of the teethIV. Relationship of upper incisor to the lower incisorV. Ability to protrude the lower incisor in front of the
upper incisor VI. Inter incisor distanceVII. Tungue sizeVIII. Visibilty of uvulaIX. Presence of heavy facial hairsX. Comliance of mandibular spaceXI. Thyromental distance with the head in maximum
extensionXII. Circumference of neckXIII. Range of motion of head and neck
EVALUATION OF THE AIRWAY
(A) History
(B) General Examination
(C) Specific Tests / indices
(D) Advanced indices
History
Patient/ notes/chart/ medic- alert
Any difficultySurgery / burnsConcurrent diseaseReflux / recent meals
II. General Examination
Starts with global assessment as soon as we see the patient.
Look for: 1. Dentition2. Distortion (edema, blood, vomits,
tumor, infection)3. Disproportion ( bull neck, large
tongue, small mouth)4. Dysmobility( TMJ and cervical spine)5. 0bese or pregnant
Speific tests / indices
A. Anatomical criteria
1. Relative to tongue/ pharyngeal size2. Atlanto occipital joint extension3. Mandibular space4. TMJ assessment
B. Direct Laryngoscopy
Anatomical criteria
Relative to tongue / pharyngeal size(mallampatti test)
Atlanto-occipital joint extensionDELLIKAN`S TESTPatient is asked to look straight ahead.
The index finger of the left hand of the clinician is placed under the tip of the jaw while the index finger of the right hand is placed on the patient's occipital tuberosity. The patient is now asked to look at the ceiling. If the left index finger becomes higher than the right, extension is considered normal.
WARNING SIGN OF DELIKAN
C. Assessment of the mandibular space
This space determines how easily the laryngeal n pharyngeal axes will fall in line when the A-o joint is extended and it also accommodates the tongue during laryngoscopy.
Assessment of the mandibular space
Thyromental distance(Patil’s test)Hyomental distanceSterno mental distance(savva test)
Thyromental Distance (Patil’s test)
Distance from the mentum to the thyroid notch.
Ideally done with the neck fully extended.
Helps determine how readily the laryngeal axis will fall in line with the pharyngeal axis.
Thyromental Distance (patil’s test)
If the thyromental distance is
short, <3 finger widths, the
laryngeal axis makes a more
acute angle with the
pharyngeal axis and it will be
difficult to achieve alignment.
Less space to displace the
tongue.
> 6.5 cm ; no problem with
laryngoscopy n intubation.
Hyomental distance
It is the distance between mentum and the hyoid bone.
It is graded as:Grade 1 - >6.0 cmGrade2 - 4 – 6 cmGrade3 - <4.0 cmGrade3 hyomental distance is
usually associated with difficult laryngoscopy and intubation.
Sternomental distance ( Savva Test)
This is measured with head in full extension and mouth closed.
<12.5 cm predicts difficult laryngoscopic intubation.
< 12.5 cm: limited neck movement
TMJ assessment
Inter incisor distanceMandibular protrusion testUpper lip bite / catch test
TMJ assessment
TMJ assessment
Upper lip bite / catch test
1. Class I: Lower incisor can bite upper lip above vermilion line
2. Class II: incisor can bite upper lip below vermilion line.
3. Class III: cannot bite upper lip.
2. Direct laryngoscopy
Cormack & Lehane grading
Grade 1: Full aperture visibleGrade 2: Lower part of cords visibleGrade 3: Only epiglottis visibleGrade 4: Epiglottis not visible
Laryngoscopic View Grades
Graded in order from the best view to worst.Grade 1: Visualization of the entire
laryngeal apeture
Laryngoscopic View Grades
Grade 2: Visualization of just the posterior portion of the laryngeal aperture . Anterior commissure not visulaized.
Laryngoscopic View Grades
Grade 3: Visualization of only the epiglottis
Laryngoscopic View Grades
Grade 4:
No glottic structure visible.
Individual indices 1) Presence of beard
2) Obesity
3)Abnormality of teeth : edentulous, irregular teeth or artificial teeth.
4) Elderly patients
5) Snorers
6) Jewellery and facial piercings
Difficult to mask ventilate: MOANS
Mask SealObesity or ObstructionAge > 55No TeethStiff
Mask Seal
Receding mandibleBurn stricturesBeardFacial Trauma
Obesity or Obstruction
Obesity
Heavy chest Abdominal contents
inhibit movement of the diaphragm
Increased supraglottic airway resistance
Difficult mask seal Quick desaturation
Age > 55 / No Teeth
Associated with difficult mask ventilation, possibly due to loss of tone in the upper airway. Face tends to “cave in”
Consider leaving dentures in for mask ventilation and remove for intubation
Stiff
Refers to Poor ComplianceReactive Airway DiseaseCOPDPulmonary Edema/Advance
PneumoniaHistory of Snoring/Sleep Apnea
GROUP INDICES
Wilson scoring systemBenumof’s analysisSaghei & safavi test
JUST A QUICK LOOK
Wilsons’ Rule for predicting difficult intubation :
5 factors into account
PARAMETER 0 1 2
WEIGHT < 90 Kg 90 – 110 Kg > 110 Kg
HEAD & NECK MOVEMENT
Above 90° About 90° Below 90°
JAW MOVEMENT IG > 5 cm (or) Slux > 0
IG = 5 cm& Slux = 0
IG < 5 cm& Slux < 0
RECEDING MANDIBLE
Normal Moderate Severe
BUCK TEETH Normal Moderate Severe
0 – Normal; 1 – Moderate; 2 – Severe patient scoring < 5-easy laryngoscopy
6-7 –moderate difficulty 8-10 –severe difficulty
BENUMOF’S 11 PARAMETER ANALYSIS
Parameter
Buck teeth Subluxation
Interincisor gap Palate configuration Mallampati class Upper incisors length TM distance SMS compliance Neck thickness Length of neck Head /neck mvt
Minimum acceptable value
<1.5cm Yes >3cmNo arching/narrowness<2 <2 cm>5 cm Soft to palpation. Qualitative ( >33cm DI) >8cm Normal range
Saghei and safavi indices
Weight > 80 kgT0ngue protrusion >3.2cmMouth opening <5 cmUpper incisor length >1.5 cmMallampati class >1Head extension < 70 degree
Any 3 indices if present prolonged laryngoscopy
LEMON
L – Look externally ( facial trauma, large incisors, beard or moustache, large tongue )
E – Evaluate the 3-3-2 rule ▪ inter incisor distance – 3 finger breadths▪ hyoid- mental distance – 3 finger breadths▪ thyroid to floor of mouth distance – 2 finger breadths
M – Mallampati O – Obstruction
▪ epiglottitis, ▪ peritonsillar abscess▪ trauma
N – Neck mobility
Advanced Indices
1. Radiographic assessment
▪ From skeletal films▪ Flouroscopy▪ Oesophagogram▪ Ultrasonograpgy▪ Computed tomography / MRI▪ Video optical intubation stylets
2. Flow volume loop3. Acoustic response measurement4. Flexible bronchoscope
Investigations (cont):
Ultrasonography Assessment of
anterior mediastinum mass
X ray & CT Scan
Flexible bronchoscope
Others Palm Print & Prayer sign:
To Summarize
Airway assessment is a critical part of the airway management.
The airway assessment must always be performed prior to ALL RSI attempts.
While these criteria help identify difficult airway, it does not guarantee an easy intubation—Be Prepared!
Difficult Airways - Assess the Risks
Develop your skills and ways to assess the airway.
There are lot of scores and numbers , adapt what suits you…..What you can remember and apply.
“The difficult airway is something one anticipates; the failed airway is something one experiences.” -Walls 2002
Thank you