Airway management and clinical implications

1. Presenter :- Dr. Sparsh Singh
Department of Anaesthesiolgy
Ganesh Das Hospital, Shillong.
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2. What is an AIRWAY?
The passage through which air passes during respiration
COMPONENTS OF THE AIRWAY
 Mouth
 Nose
 Pharynx
 Larynx
 Trachea
 Mainstem bronchi
2

3. LARYNX
 Cartilaginous skeleton held together by ligaments and
muscle.
 Extends from laryngeal inlet(C3-C4) to lower border of
cricoid cartilage (C6).
 Composed of 9 cartilages – Unpaired: Thyroid
Cricoid
Epiglottis
Paired: Arytenoid
Corniculate
Cuneiform
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4. 4

5.  The muscles of larynx are supplied by recurrent
laryngeal nerve except cricothyroid which is
innervated by external laryngeal nerve.
 The posterior cricoarytenoid muscles abducts the
vocal cords whereas the lateral cricoarytenoid muscles
are the principal adductors.
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6. FUNCTIONS OF AIRWAY
 Air conduction
 Warming
 Filtration
 Humidification
 Removal of foreign particles
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7. WHY ASSESSMENT IS
IMPORTANT?
Assessment of airway helps in
 Optimal patient preparation
 Proper selection of equipment and technique
 Participation of personnel experienced in the difficult
airway management
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8. What to look for?
 Facial anomalies like maxillary hypoplasia (apert syndrome,
crouzon syndrome), mandibular hypoplasia(pierre robin
syndrome, treacher collins syndrome)/hyperplasia (acromegaly,
cherubism).
 Temporomandibular joint pathology
 Anomolies of mouth and tongue like microstomia, ludwigs
angina, tumors of mouth and tongue, macroglossia.
 Problems with teeth – missing or buck tooth
 Anomaly of the nose like choanal atresia, hypertrophic
turbinates, DNS
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9. Cntd.
 Pathology of palate like narrow arched palate, cleft
defects, soft palate swelling and hematomas.
 Pathology of pharynx – hypertrophic tonsils and
adenoids, tumors and abscesses.
 Pathology of larynx – epiglotitis, laryngomalacia,
granuloma, stenosis, inflammatory edema.
9

10. Causes for difficulty in mouth
opening
 Ankylosing spondylitis
 Rheumatoid arthritis
 TMJ fixity
 Scleroderma
 Local acute infection
 Localized tumor
 Circumoral burns with scarring
10

11. Causes for difficulty in head
extension
 Ankylosing spondylitis
 Rheumatoid arthritis
 Cervical spondylitis or fusion
 Scleroderma
 Cystic hygroma
 Large hydrocephalus and encephalocele
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12. AIRWAY ASSESSMENT
A preanesthetic airway assessment is mandatory before
every anesthetic procedure. Several anatomic and
functional maneuvers can be performed to estimate the
difficulty of endotracheal intubation.
• Mouth opening – an incisor distance of 3 cm or
greater is desirable in an adult.
• Mallampati classification – it examines the size of
tongue in relation to oral cavity.
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13. MALLAMPATI CLASSIFICATION
 Class I: entire palatal arch, bilateral faucial pillars
is visible down to the bases of the pillars
 Class II: upper part of faucial pillars and most of
the uvula are visible.
 Class III: soft and hard palates are visible
 Class IV: only hard palate is visible
Class III and IV → Difficult to Intubate
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14. 14

15.  Thyromental distance – distance between the
mentum and the superior thyroid notch. A distance
greater than 3 fingerbreadths is desirable.
 Neck circumference – greater than 17 inches is
associated with difficulties in visualization of glottic
opening.
15

16.  Hyomental distance –
grade 1 - >6 cm
grade 2 – 4 – 6 cm
grade 3 - <4 cm (usually associated with impossible
laryngoscopy and intubation)
Sternomental distance – measured with head in full
extension and mouth closed. A distance of <12.5 cm
predicts a difficult laryngoscopic intubation.
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17. DIFFICULT AIRWAY
 A clinical situation in which a conventionally trained
anesthesiologist experiences difficulty with mask
ventilation, difficulty with tracheal intubation or both.
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18. DIFFICULT MASK VENTILATION
 It is not possible for the unassisted anesthesiologist to
maintain SPO2>90% using 100% O2 and positive
pressure mask ventilation in a patient whose SPO2 was
> 90% before anesthetic intervention and/or It is not
possible for the unassisted anesthesiologist to prevent
or reverse signs of inadequate ventilation during
positive pressure mask ventilation
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19. SIGNS OF INADEQUATE MASK
VENTILATION
• Absent or inadequate chest movement.
• Absent breath sounds.
• Gastric air entry or dilatation.
• Cyanosis.
• Haemodynamic changes due to hypoxia or
hypercarbia.
• Decreasing oxygen saturation.
• Absent or inadequate exhaled CO2
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20. PREDICTORS OF DIFFICULT MASK
VENTILATION
 BEARDED
 OBESE (>26KG/M2) AND UPPER AIRWAY
OBSTRUCTION
 NO TEETH (EDENTULOUS)
 ELDERLY (>55 YEARS)
 SNORERS
OTHER CRITERIA:-
 MOANS
20

21. HAN’S SCALE OF DIFFICULT MASK
VENTILATION
I. VENTILATED BY MASK
II. VENTILATED BY MASK WITH ORAL/NASAL AIRWAY
WITH / WITHOUT MR
III. DIFFICULT MASK VENTILATION WITH/ WITHOUT
MR
IV. UNABLE TO MASK VENTILATE WITH/WITHOUT MR
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22. DIFFICULT LARYNGOSCOPY
 It is not possible to visualize any portion of the vocal
cords with conventional laryngoscope (ASA
definition).
22

23. DIFFICULT ENDOTRACHEAL
INTUBATION
 Proper insertion of the tracheal tube with
conventional laryngoscopy requires more than 3
attempts or more than 10 minutes.
23

24. INTUBATION ATTEMPT
 An intubation attempt is defined as “Intubation
activities occuring during a single continuous
laryngoscopy maneouver”.
 Thus, even if several attempts were made to place an
ETT during the course of a single laryngoscopy, it
would be counted as a single intubation attempt.
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25. BEST ATTEMPT LARYNGOSCOPY
 Laryngoscopy performed by reasonably experienced
laryngoscopist with the patient in optimal sniff
position having no significant muscle tone and the
laryngoscopist has an option of change of blade type
and length .
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26. PREDICTORS OF DIFFICULT LARYNGOSCOPY
AND TRACHEAL INTUBATION
DIRECT ASSESSMENT
 Reduction of a-o extention:
1. No reduction
2. 1/3rd reduction
3. 2/3rd reduction
4. Complete reduction
2/3rd or complete reduction is a clear pointer to
difficult rigid laryngoscopy.
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27.  Delikan’s test – assesses movement of occiput on
atlas during extension.
 Prayer sign - The patient cannot bend their fingers
backwards while approximating palms. Seen in long
term juvenilediabetic patients due to stiff joint
syndrome.
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28. 28

29.  Palm print sign:
Patient’s fingers and palms painted with
blue ink and pressed firmly against a white paper.
0 - all phalangeal areas visible
1 - deficient interphalangeal areas of 4th and 5th digits
2 - deficient interphalangeal areas of 2nd to 5th digits
3 - only tips seen
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30. 30

31. ASSESSMENT OF TMJ FUNCTION
TM joint exhibits 2 functions:
 Rotation of the condyle in the synovial cavity.
 Forward displacement of the condyle.
First movement is responsible for 2-3cm mouth opening and
the second is responsible for further 2-3cm mouth opening.
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32. SUBLUXATION OF THE MANDIBLE
Index finger is placed in front of the tragus & the thumb
is placed in front of the lower part of the mastoid
process. Patient is asked to open his mouth as wide as
possible. Index finger in front of the tragus can be
indented in its space and the thumb can feel the sliding
movement of the condyle as the condyle of the mandible
slides forward.
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33. CALDER TEST
 The patient is asked to protrude the mandible as far as
possible. The lower incisors will lie either anterior to,
aligned with or posterior to the upper incisors.
 The latter two suggest reduced view at
laryngoscopy.
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34. LEMON ASSESSMENT
L - Look externally (facial trauma, large incisors, beard,
large tongue)
Evaluate 3-3-2 rule
3 - Inter incisor gap
3 - Hyomental distance
2 - Distance between thyroid cartilage and floor of
the mouth.
M – Mallampati grade
O - Obstruction (epiglottitis, quinsy)
N - Neck mobility.
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35. WILSON SCORING
 5 factors – Weight
Upper cervical spine mobility
Jaw movement
Receding mandible
Buck teeth
 Each factor: score 0-2
 Total score < 5 – Easy laryngoscopy , 6 to 7 - Moderate
difficulty, > 7 - Severe difficulty
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36. 36

37. RULE OF 1-2-3
 1 finger breadth for subluxation of mandible.
 2 finger breadth for adequacy of mouth opening.
 3 finger breadth for hyomental distance.
In emergency situation, above test can be rapidly performed
within 15sec to assess the TMJ function , mouth opening and
SM Space.
Significant difficulty in 2 or more of these components
requires detailed examination.
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38. RULE OF THREE
 3 finger in the interdental space.
 3 finger between mentum and hyoid bone.
 3 finger between thyroid cartilage & sternum
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39. X-RAY
 X-Ray neck (lateral view)
• Occiput - C1 spinous process distance < 5mm.
• Increase in posterior mandible depth > 2.5cm.
• Ratio of effective mandibular length to its posterior
depth <3.6.
• Tracheal compression.
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40. FOUR D’s OF DIFFICULT AIRWAY
ASSESSMENT
 Dentition (prominent upper incisor, receding chin)
 Distortion(edema, blood, vomitus, tumor, infection)
 Disproportion(short chin to larynx distance, bull
neck)
 Dysmobility(TMJ and cervical spine pathologies)
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41. 41

42. What does ASA 22 say?

46. Three ‘nonsurgical’techniques to establish a patent airway
If a ‘best effort’at any of the three lifelines is unsuccessful, this mandates spiral movement
inward to the next lifeline
Failure to establish patent airway after best effort at all three lifelines culminates in arrival
at the central zone to initiate ‘CICO rescue’FONA

49. AIDAA
recommendations
• Assessment
• None of the available tests are reliable
• Always be prepared for difficult airway
• Preparation
• Pre-oxygenation and peri-intubation oxygenation
• Head-up position 200
• Tidal volume breath for 3 mints
• 8 vital capacity breaths for 60 secs
• 10 L/min of O2
• Target ETO2 > 90% & N2 < 4%
• CPAP & PSV
• Apnoeic Oxygenation through 15L/min Nasal O2
• THRIVE

50. • Laryngoscopy and Intubation – failed
– Call for help, continue oxygenation 15L/min
– Maximum 2 more attempts
– Repeat only if SpO2 > 95%
– Change plans after first attempt, optimise position etc
– Blind insertion in grade 3b & 4 is not recommended
• Confirmation of intubation

51. • SAD – 2nd generation
• High sealing pressure
• Max 2 attempts
• Only 4.2% of devices inserted successfully at the third
attempt.

52. RESCUE STRATEGIES:
• Continue nasal Oxygen 15L/min
• One final attempt at mask ventilation
• Use optimal technique and adjuncts,
• Ensure complete neuromuscular blockade,

53. p
• VENTILATION FAILURE PRECEEDS OXYGENATION FAILURE
• AIDAArecommends proceeding to emergency cricothyroidotomy when there is CVF,
EVEN IF oxygenation is maintained and not when hypoxaemia sets in.
• CALLFORADDITIONALHELP
• CONTINUEATTEMPTSAT OXYGENATION THROUGH UPPERAIRWAY
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What should be the Trigger?

54. CALL FOR
ADDITIONAL
HELP
• Complete ventilation failure (CVF)
• Situation where intubation, ventilation using SAD and face mask
have all failed after giving the best attempt, even if oxygenation
may be maintained

55. • Position
• Landmark – cricothyroid membrane
• Laryngeal Handshake

56. Direct / VL (max 3+1 attempt)
2nd generation SAD
Change device or size (max 3 attempts)
Oxygenate & ventilate
If facemask ventilation impossible, paralyse
Final attempt of facemask ventilation
Use 2 person technique
Declare CICO
Surgical Cricothyroidectomy

57. 2008 DAS 2015 DAS 2016AIDAA
CICV CICO CVF
Terminologies

58. Obstetrics
• Incidence of difficult airway 1 in 224, 8 times more
• Always full stomach
• Decreased OES pressure
• Increased chance of aspiration
• Rapid desaturation
• Assess the front of neck access
• Priority is for mother’s safety

59. • HELP, RSI, One more attempt in optimum condition
• Gentle IPPV withAPL valve closed to < 20 cm H2O
• Release Cricoid pressure partial or complete

60. Mother sustains Cardiac arrest:
• Perform CPR with left uterine displacement
• Perform Caesarean delivery within 4 mins of
cardiac arrest

61. • One more attempt - Max 2 attempts
• Final attempt (3rd ) should be allowed only by an anaesthesiologist with
paediatric experience
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62. • CVF is very rare
• Technical difficulty of locating the correct anatomical structures
• Emergency rescue should not be delayed till there is desaturation
• Needle cricothyrotomy / transtracheal needle puncture should be replaced with
tracheostomy within 40 mins

64. sT
OP

66. Game plan
• Assess airway
• Perioxygenate
• SpO2 < 95% as cut off for escalating airway interventions
• Limit the no of intubation & SAD attempts as per the guidelines
• Never hesitate to call for additional help
• CVF the trigger for Emergency Crico (Stab – twist – bougie – tube)
• Have a Post Procedural Plan and Standard reporting UADA
• Never use a guideline and a equipment for the first time in crisis
• Follow a guideline which best fits as per your limitations
• Preparedness and rehearsal are the key to overcome crisis

67. REFRENCES
1. Miller's Anesthesia 9th edition
2. Clinical Anesthesiology, 5th Edition,G.
Edward Morgan, Jr., Maged S. Mikhail, Michael J.
Murray
3. Rashid M Khan Airway management, 7th
edition