1. - B Y G. S U R Y A 1 S T
Y E A R PG
M O D E R A T O R - D R . M A D HU S U D HA N S IR
( A S S O C I A T E P R O F E S S O R )
DIFFICULT AIRWAY
2. What is airway?
The passage through which the air passes during
respiration.
What is difficult airway?
ASA defined difficult airway as trained
anaesthesiologist experiences difficulty with mask
ventilation,difficulty with tracheal intubation or
both.
3. Difficult mask ventilation:
Not possible for the unassisted anaesthesiologist to
maintain oxygen saturation more than 90% using
100% oxygen and postive pressure mask ventilation
in a patient whose oxygen saturation was more than
90% before anaesthetic intervention.
4. Difficult laryngoscopy:
Not possible to visualise any portion of the vocal
cords with conventional laryngoscope.
Difficult endotracheal intubation:
Proper insertion of the tracheal tube with
conventional laryngoscopy requiring more than 3
attempts or > 10 minutes.
5. ANATOMY OF AIRWAY
Airway is divided into two :
1) upper respiratory tract
2) lower respiratory tract .
Above vocal cord is upper respiratory tract which
include nose ,sinuses, pharynx and larynx.
Below vocal cord is lower respiratory tract which
include trachea , bronchi and alveoli.
6. Sensory nerve supply of airway
Mucous membrane of the nose – innervated by
ophthalmic division of trigeminal nerve ( anterior
ethamoidal nerve)anteriorly and maxillary division
posteriorly (sphenopalatine nerves)
Glossopharyngeal nerve innervate pharynx ,tonsil
and soft palate.
7. Vagus nerve - superior and recurrent laryngeal
nerve provide sensation below epiglottis.
Internal laryngeal nerve supplies innervation
between epiglottis and vocal cord .
Recurrent laryngeal nerve provide sensation below
vocal cord.
Motor supply – both adductor and abductor of vocal
cord is supplied by RLN except cricothyroid supplied
by ILN .
9. Difference between adult and pediatric airway
Anatomy Paediatric Adult
tongue large small
Epiglottis
shape
Floppy,omega shaped Firm ,flatter
trachea Smaller,shorter Wider and longer
Larynx shape Funnel shape column
Larynx
position
Angle posteriorly away from glottis Straight up and down
Narrowist
point
Subglottic region At level of vocal cords
lung volume 250ml at birth 6000ml at adult
10. Predictor for difficult bag and mask ventilation
Presence of Beard- create difficulty in effective seal by mask
leading to loss of ventilated volume.
Obesity- BMI > 26kg/m greater risk of difficult mask ventilation.
Abnormality of teeth-
Artificial denture = should be removed after well ventilated.
Edentulous = placing unfold gauze along buccal area restore
cheek fullness and help to create optimal mask seal.
Elderly patient - > 55years
Snorers- application of positive airway pressure (5-10 cm h20)
while ventilating help in keeping airway patent.
BONES- patient having 2 or > of these predictor have difficult
mask ventilation.
11. Predictor for difficult laryngoscopy and tracheal intubation
Assessment of cervical and A-O joint function:
Neck is flexed on the chest by 25 -35 degree and A-O
joint is well extended 85 degree.
This is called sniffing or magill’s position.
12. Delikan’s test: assess movement of occiput on the
atlas during extension.
Head is held in neutral position
Index finger of left hand of the clinician is placed
under tip of jaw while index finger of right hand is
placed in occipital tuberosity.
Now pt is asked to look ceiling
If left index finger become higher than right normal
If left finger remains at same level or low abnormal
14. Palm print test
To assess difficult laryngoscopy in diabetic patient.
This test is based on hypothesis that joint rigidity seen
in diabetic is due to tissue glycosylation and it may
involve laryngeal and cervical joint leading to
difficult laryngoscopy.
Here pt palm print is kept on white paper over firm
surface. Scoring is done as follow
15. 0 - phalangeal area complete visible
1 – interphalangeal digit of 4th
and 5th
digit partly
visible
2- interphalangeal area between 2nd
and 5th
hardly
visible
3- only fingertip printed
Higher the score difficult the intubation.
17. Assessment of TMJ function
Function of TMJ is
Rotation of condyle in synovial cavity
Forward displacement of condyle
Two test
1) Ask the pt to open his mouth wide and place his three
finger (index,middle and ring) if done this is> 5cm
which is adequate for laryngoscopy.
2) Index finger is placed in front of tragus and thumb over
front of lower part of mastoid process as condyle
slide forward,through index finger you can feel sliding
of the condyle
18. Calder test
B and C will have reduced view during laryngosopy.
19. Thyromental distance – distance between thyroid
notch and mental symphysis when neck is fully
extended.
>6.5 cm : no problem with scopy and intubation
< 6cm : laryngoscope is difficult.
Hyomental distance: distance b/w mentum and
hyoid bone.
grade I : > 6cm
grade II : 4-6cm
grade III : < 4cm ( difficult laryngoscopy)
20. Assessing the adequacy of oropharynx for laryngoscopy and
intubation
Mallampati grading : indicate amount of space
present in oral cavity to accomadate laryngoscope
and ETT.
grade I – faucial pillars,uvula,soft and hard palate.
grade II – uvula , soft and hard palate
grade III – base of uvula or none , soft and hard
palate
grade IV – only hard palate.
22. Cormack lehane laryngoscopic view
Grade I- visualization of entire vocal cords
Grade II – visualization of posterior part of laryngeal
aperture.
Grade III – visualization of epiglottis
Grade IV – no glottic structure seen.
Grade III and IV – difficult in intubation
23. Wilson scoring system
Less than 5 score – easy laryngoscopy
6-7 moderate difficulty
8-10 severe difficult.
24. Benumof ‘s 11 parameter analysis
4-2-2-3 rule
4 parameter focusing on teeth, 2 on inside mouth,2
for mandibular space and 3 in neck examination.
25. Arne`s simplified score model for difficult intubation
Score of > 11 is predictive of difficult tracheal
intubation.
40. Difficult airway trolley
Drawer 1 – plan A (intubation)
content :
Laryngoscope blades- macintosh size 3 & 4,miller
sizes 2& 3 , McCoy.
Laryngoscope handle- standard , stubby handle
ETT
Stylet and magill forcep
41. Drawer 2 – plan B (oxygenation via SAD)
Content:
two different types of second generation SADs( I-
GEL, Proseal) size 3,4,5
orogastric tube
intubating LMA
42. Drawer 3 – plan C ( mask ventilation)
Content:
facemask of various size
oropharyngeal airway – different size
nasopharyngeal airway- different size
43. Drawer 4 plan D –(Emergency invasive airway)
Content:
surgical cricothyroidotomy set( 6 size ETT , surgical
blade ,bougie)
needle cricothrotomy set
45. Benefit of awake airway intubation
Helps in preservation of pharyngeal muscle tone and
patency of upper airway.
Maintenance of spontaneous ventilation
Used in unstable cervical spine pathology and
restricted mouth opening.
47. Splenopalatine block :
splenopalatine ganglion located posterior to middle
turbinate , it supply sensory to nasal cavity, roof of mouth,
soft palate and tonsil.
It is blocked by placing cotton swab stick with 4% lignocaine
along upper border of middle turbinate ,untill posterior wall
is reached.
Anterior ethamoidal block:
provide sensory innervation to anterior portion of nasal
cavity.It’s blocked by placing cotton swab stick 4% lignocaine
on the dorsal surface of nasal cavity ,untill cribriform plate.
48. Glossopharyngeal block
It supplies posterior part of tongue and oropharynx .
Intra oral approach:
It is blocked by injecting 2ml of lignocaine on both side
into the base of the palatoglossal arch ( ant tonsillar
pillar)
Extra – oral approach:
useful in case of decreased mouth opening.
At midpoint of the line joining the mastoid process and
the angle of jaw , needle is inserted perpendicularly to hit
styloid process , redirected posteriorly and LA is injected
50. Superoir laryngeal nerve block
Bilateral SLN blocks anaesthetize the airway below
epiglottis.
Hyoid bone is palpated and 1cm below each greater
cornu 3ml of 2% lidocaine is infiltrated where the
internal branch of RLN penetrate thyrohyoid
membrane.
51. Translaryngeal block
It is performed by identifying and penetrating
cricothyroid membrane with neck extended and
intratracheal position is confirmed with aspiration of
air .
4ml of 4% lidocaine is injected into trachea at end of
expiration.
Deep inspiration and cough following injection
anaesthetize whole trachea.
53. Technique of fiberoptic intubation
Explain procedure and reassure the patient.
Consider antisialogue and administer nebulized lignocaine
Test FOB whether functioning properly
Remove airway connector from end of ETT and apply
lignocaine for lubrication.
Insert tip of FOB into mouth / nasal cavity
FOB advanced into glottic region and ETT is pushed into
trachea
Remove FOB and inflate ETT cuff , reconfirm position by
auscultation.
55. Retrograde intubation
Left hand is used to stabilize trachea , thumb and
third digit is placed either side of thyroid cartilage.
Through index finger cricothyroid membrane is
palpated and small incision is made ,touhy needle is
inserted and aspiration is done to confirm postion.
Epidural catheter is inserted into trachea and tongue
is pulled anteriorly to prevent coiling of catheter
Catheter will exit from oral or nasal end.
56. Then catheter was threaded through the main distal
lumen ( beveled portion) of ET .
Bourke and levesque modified the technique by
threading the catheter through murphy eye
Reason behind this is it allow additional 1cm of ETT
to pass through the cords.
Now epidural catheter is replaced with angiocatheter
58. comitube
It contain large proximal oropharyngeal cuff inflated
with 100ml air.
Distal esophageal or tracheal cuff .
Two lumen will be present
one at distal to proximal cuff
second b/w peoximal and distal cuff with 8 small
ventilating port
