The document outlines key aspects of airway assessment in anesthesia, including airway anatomy, predictors of difficult airway management, and the components of airway evaluation. It emphasizes the importance of thorough history taking and physical examination to identify potential challenges in mask ventilation, laryngoscopy, and intubation. Various indices and grading systems for assessing airway difficulty are discussed, highlighting the need for proper assessment to prevent complications during anesthesia.

1. Airway Assessment
PRESENTOR:DR.VIGNESH DURAIRAJ
MODERATOR:DR.VIVEKANANTHAN

3. • AIRWAY ANATOMY
• HISTORY TAKING
• PHYSICAL EXAMINATION
• PREDICTORS OF DIFFICULT MASK VENTILATION
• PREDICTORS OF DIFFICULT LARYNGOSCOPY AND
INTUBATION
• PREDICTORS OF SUPRAGLOTTIC AIRWAY DEVICE
INSERTION
• PREDICTORS OF DIFFICULTY IN SURGICAL AIRWAY
ACCESS.

4. Incidence

5. What is an airway?
The passage through which the air or gas passes
during respiration.
Airway can be divided into upper and lower airway.
Upper airway includes oral cavity, nasal cavity,
pharynx and larynx.
Lower airway includes trachea,bronchi,bronchioles,
alveoli.

8. Upper airway
• Oral cavity - mouth opening to anterior tonsillar
pillar.(lips,teeth,cheek,tongue)
• Nasal cavity -naris to end of the
turbinates.(Floor,roof,lateral wall,medial wall)
• Nasopharynx - posterior end of turbinate to posterior
pharyngeal wall above the soft palate.(adenoids)
• Orophaynx -soft palate to epiglottis.
(Tonsils,uvula,epiglottis,vallecula).
• Larynx - laryngeal inlet(C3-C4) to lower border of
cricoid cartilage(C6)

9. Lower airway
• Trachea extends from lower border of cricoid
cartilage (C6) to its division into brochi(T4).
• Trachea divides at carina into left[45 to 55 ] and
right(20 to 25) main bronchus .
• Bronchi
• Brochioles which branch and end up in alveoli.

10. Why assessment is important?
• Main purpose is to predict difficult airway .
• The ASA defined a difficult airway as
• Proper selection of equipment and technique.
• Optimal patient preparation.
• Participation of experienced personnel.
The clinical situation in which a conventionally trained
anesthesiologist experiences difficulty with mask
ventilation,difficulty with tracheal intubation or both.

11. Components of airway
assessment
• Proper history taking, general examination and
specific test to predict difficult airway.
• Four pillars of airway management include
1.Mask ventilation
2.Laryngoscopy and tracheal intubation
3.Placement of supraglottic device
4.Performing surgical access to airway.

12. History taking
• Some features of patients' medical history or records may point to
difficult airway.
• Previous history of difficult airway.
• History of joint disorders like Ankylosing spondylitis,RA,
scleroderma,etc..
• History of irradiation to Head and neck.
• History of previous cervical spine surgeries,Head and neck surgeries.
• History of burns which may lead to fibrosis.
• History of trauma

13. FACIAL ANAMOLIES
Cleft lip,cleft palate
Mandibular and maxillary
hyperplasia
Traumatic /surgical
disfigurement
NASAL CAVITY
DNS,hypertrophic
turbinates
Tumour,foreign body
Choanal atresia
PHARYNX
Hypertrophic tonsils and
adenoids
Tumours
Retro/parapharyngeal
abscess
Swelling of uvula
ORAL CAVITY
Microstomia
Macroglossia,narrow
arch
Protruded or loose or
missing tooth
Tumour,Ludwig.
angina

14. LARYNX
Epiglottitis
Foreign body
Tumour,edema
Laryngomalacia
Congenital stenosia
LOWER AIRWAY
Tracheo osophageal
fistula
Tracheitis
Foreign body
Bronchial Tumour
Mass displacing trachea

15. MASK VENTILATION
• Mask ventilation is a
noninvasive technique for
airway management that can
be used as a primary mode of
ventilation for an anesthetic of
short duration or as a bridge to
establishing of a more
definitive airway.
• The ability to ventilate the
patient always remains the
crucial .

16. Difficult mask ventilation
• The ASA task force defines it as occurring when "it is
not possible for the unassisted anesthesiologist to maintain
Oxygen saturation >90% using 100% O2 and positive
pressure mask ventilation in a patient whose saturation was
more than 90% before anaesthetic intervention and /or,it is
not possible for unassisted anesthesiologist to prevent or
reverse signs of inadequate ventilation during positive
pressure mask ventilation .
• It is not possible to provide adequate ventilation (confirmed
by etCO2),because of one or more of the following
problem:inadequate mask seal,excessive gas leak or
excessive resistance to ingress or egress of gas.

17. PREDICTORS OF DIFFICULT MASK
VENTILATION
INDIVIDUAL INDICES
1.Presence of beard
2.OSA or h/o snoring
3.Obesity > 30kg/m2
4.Elderly patient > 55 years
5.Abnormality of teeth,edentulous
6.Mallampatti 3 or 4
7.Male gender
8.Hair bun

18. GROUP INDICES
• BONES(Beard,Obese,No teeth,Elderly,Snore)
• OBESE(Obese,Beard,Elderly,Snore,Edentulous)
• MIMS(Male,Increasing age,Mallampatti 4,Snore)
• MOANS (Mask seal difficult,Obese,Advanced age,No
teeth,Snorer)

19. PREDICTORS OF DIFFICULT
LARYNGOSCOPY AND TRACHEAL
INTUBATION
• The ASA defined difficult laryngoscopy as occuring
when"It is not possible to visualize any portion of
vocal cords with conventional laryngoscope. "
• No visualization of vocal cords despite multiple
attempts at laryngoscopy.
• The ASA defined difficult endotracheal intubation as
occurring when"Proper insertion of tracheal tube
with conventional larynsgoscopy requires more than
three attempts or >10 minutes.

20. INDIVIDUAL INDICES
Physical examination indices
1.Assesment of cervical and atlanto occipital joint
function .
2.Assesment of TMJ function
3.Upper lip bite test
4.Assesment of mandibular space
5.Adequacy of oropharynx for laryngoscopy
6.Assesment of quality of glottic viewing.
7.Sternomental distance
8.Thyroid to floor of mouth
9.Symmetry of upper and lower face
10.Neck circumference and length of neck

22. Sniffing position or Magill's
position
• Flexion at neck and extension at atlanto occipital
junction facilitates the sniffing position.
• Normal flexion should be > 25 to 30
• Normal Extension should be > 80 to 85
• Normal head /neck rotation should be > 70 to 75.

23. Cervical and atlanto occipital joint
function
• Direct assessment
Ask the patient to
touch his manubrium
sternum with his/her
chin.
Ask the patient to
look at the ceiling
without raising
eyebrows.
• Indirect assessment
Prayer sign (stiff
joint syndrome)
Palm print
test(tissue glycosylation)

25. Assessment of TMJ function
• Rotational and forward movement of the condyle
are tested.
• Ask the patient to wide open his mouth and place
his three fingers[index,middle,ring].If done ,this is >
5cm and is adequate.[se-22,spe-94】.
• Index finger - infront of tragus ,thumb- lower part of
mastoid process behind the ear .Ask the patient to
open the mouth.
• CALDER TEST -Protrude the mandible as far as
possible

27. Upper lip bite test
• It test the range and freedom of mandibular
movement and the architecture of the teeth.
• Class 3 will correspond to CL 3 or 4. ( se 67,spc 92)

28. Assessment of mandibular space
• This space accompaines the tongue pushed by the
laryngoscopy blade and it also determines how easily
the laryngeal and pharyngeal axis will fall in line when
head is extended.
• HYOMENTAL DISTANCE
Distance between hyoid and mentum when the
neck is fully extended. Grade 3-impossible laryngoscopy
and intubation
Grade 1 :>6cm
Grade 2: 4 to 6 cm
Grade 3:<4cm

29. Distance between thyroid notch
and mentum when the neck is fully
extended.
>6.5cm -no problem
6- 6.5cm- without other
concomitant anatomical
problems,possible
<6cm - maybe impossible
A modified version is thyromental
distance which is ameasure of
vertical height between anterior
border of thyroid cartilage and
mentum.sensitivity of 83 and
specificity of 99
THYROMENTAL DISTANCE

30. Adequacy of oropharynx for
laryngoscopy and intubation
• MALLAMPATTI grading
It indicates the amount of space within the oral
cavity in relation to the size of the tongue.
Patient in sitting position,head protrudes forward
and ask the patient to open the mouth as wide as
possible and stick out the tongue without phonation
.Based on the structures visible, grading is given.
Nowadays we use modified Mallampatti proposed by
samsoon and young.

31. Class 1 - PUSH[91.2]
Class 2-USH[6.3]
Class 3-SH[2.1]
Class 4 -H[0.4]
Class 0

33. Quality of glottic
viewing during
laryngoscopy
• It can be done by
indirect mirror
laryngoscopy and
direct
laryngoscopy
awake look.
• They provide
better data than
Mallampatti
grading.

35. POGO scoring
• Percentage of glottic opening seen while directly
visualizing through a scope.
• Entire aperture visible -100%
• If only lower portion of vocal cord and arytenoids
seen - 33%
• When no glottic structure visible - 0 %

36. Sternomental distance
• It is measured from sternal notch to mentum with
head in full extension and mouth closed.
• Value of less than 12.5 cm predict difficult
intubation.
• Sensitivity of 82 and specificity of 89 % .
•Symmetry of upper and lower face
• Upper face- bridge of nose to nasal septa at upper
lip.Lower face- from septa to mentum.
• If lower face > upper face,then the difficult line up
should be expected.

37. Neck circumference
• It is commonly increased in obese group of people.
• Men having circumference >17 inch and women
having >16 inch have high risk for difficult
intubation.
• Short neck also a risk factor.

38. Radiological and advanced indices for
predicting difficult airway
• Lateral xray of neck along with marking between
bony landmarks
Distance between occiput and spinous process of
C1 shoulld be > 5mm
Increase in posterior depth of mandible >2.5 cm
poses problem during laryngoscopy
• Ratio of effective mandibular length to its
posterior depth that is <3.6 predict difficult
laryngoscopy.
• Volume loop curves,mri,fluoroscopy and
oesophagogram can also be used.

39. Ultrasonography
Useful in
Identification cricothyroid membrane
Localisation of trachea
Quantifying the soft tissue in anterior neck in
obese for predicting difficult intubation.Distance from
skin to anterior aspect of trachea in three zone is
measured and averaged.If average is more than
28mm then it is difficult laryngoscopy.
Zone 1 - vocal cords
Zone 2- thyroid isthmus
Zone 3- suprasternal notch

40. Group indices
• Wilson scoring system
• benumof 11 parameter analysis
• Lemon law
• Ali magbouls four D
• Rapid airway assessment can be done less than 15
sec in emergency situation.1-2-3finger assessment
test
• 1 finger- tmj joint movement
• 2finger-mouth opening
• 3 finger - thyromental distance

43. Predictors of difficult placement
/subsequent ventilation with
supraglottic devices
•Restricted mouth opening
•Obstruction of the upper airway
•Disrupted upper airway as following trauma,burns
•Stiff lung (poor lung or thoracic complaine)

44. Predictors of difficulty in surgical
airway
•Bleeding tendency
•Agitated Patients
•Neck scarring and neck flexion deformity
•Growth or vascular abnormalities in region of
surgical airway.

45. There is no single method or indicator
which can detect 100% of difficult airway.
Anaesthesia related death are 1 in
10000.Of these 1 in 4 case is due to
difficult airway.
Regret is always the worst.So ,do a
proper airway assessment for each
case.