anatomy and assessment of airway

1. Presentor -Dr. Amey Dixit
Moderator-Dr. R. Dwivedi (M.D.)
2nd year PG resident
1/2/2020
S S MEDICAL COLLEGE REWA MP

2. DEFINATION
 Airway is defined as a passage through which
the air/gas passes during respiration.
OR
 In practice of airway management it is described as any
artificial device with a lumen to aid ventilation&/or serve
as a conduit to endotracheal intubation.
These include- Nasopharyngeal airway
Oropharyngeal airway
Laryngeal mask airway

3. CLASSIFICATION OF AIRWAY
1)UPPER AIRWAY-
Oral cavity, Nasal cavity, Pharynx, Larynx
MOST VULNERABLE AREA FOR OBSTRUCTION
2)LOWER AIRWAY–
Trachea, Bronchi, Bronchioles, Alveoli
SIGNIFICANCE-
 Upper airway serves to warm, filter, humidify the air/gas before it enters the lower
airway. Bypassing these structures during ETT Intubation ,makes it essential to provide
warm humidified air/gas while patient breath spontaneously or are on assisted/
controlled ventilation.
 Lower airway serves in exchange of gases.

4. ORAL CAVITY
 Extends from lips to oropharyngeal isthmus (i.e. Anterior tonsillar pillar.)
 Tongue is a muscular organ which makes up most of the floor of oral cavity.
Genioglossus most clinically relevant to anesthesiologist which connects the
tongue to the mandible.
BOUNDARIES-
 ROOF Hard and soft palates
 FLOOR Soft tissues, which include a muscular
diaphragm and the tongue
 LATERAL WALLS Cheeks
 POSTERIOR aperture of the oral cavity is the
oropharyngeal isthmus

5. MUSCLES OF TONGUE
Extrinsic Muscles - Intrinsic Muscles-
Alter the position of the tongue Alter the shape of tongue
1. Genioglossus ( safety muscle of tongue) 1. superior longitudinal muscle
2. Hyoglossus 2. Inferior longitudinal muscle
3. Styloglossus 3. Transverse muscle
4. Palatoglossus 4. Vertical muscle
 Nerve supply:
All muscles (intrinsic & extrinsic ) of the tongue are supplied by hypoglossal nerve, except
palatoglossus which is supplied by cranial part of accessory nerve (pharyngeal plexus).

6. SIGNIFICANCE-
 Mallampati grading helps in assessment of airway during PAC.
 JAW THRUST MANUEVER-
This maneuver uses the sliding component of
temporomandibular joint to move the mandible and
attached tongue anteriorly relieving airway obstruction
caused by posterior displacement of tongue into
oropharynx (During sleep, decreased consciousness,
during general anesthesia).
 Caution should be maintained during laryngoscopy as lips can be injured
 Loose/bucked tooth can lead to difficult intubation
 Depletion of buccal fat (old age) –Difficult mask ventilation.

7. NOSE AND NASAL CAVITY
Nose is divided into two regions-
EXTERNAL NOSE INTERNAL NOSE
- Bony part - Vestibule
- Cartilaginous part - Nasal cavity proper Medial wall
EXTERNALLY ALAE NASI - Lateral wall
 Lateral margins of the nostrils. Rounded & mobile Roof
 Flaring of ala nasi Airway obstruction Floor
 Infolded while introducing any tube via the nostril
 Distance from alae nasi to various points on external ear( tragus, meatus)
Estimate the length of airway device introduced for relieving airway obstruction

8. Lateral wall: Lateral wall of nasal cavity has 3 conchae
(turbinates) and opening of paranasal sinus.
APPLIED ANATOMY:
 Inferior meatus is the preferred pathway for passage of nasal airway device; Improper
placement of object in nose can result in avulsion of a turbinate.
 Prolonged nasotracheal intubation has most often associated with infection of maxillary sinus
due to obstruction and lack of drainage through ostia.
Medial wall: Nasal septum form the medial wall
Has highly vascular little’s area in the
anterior inferior part of nasal septum.
APPLIED ANATOMY:
 This is the commonest site of epistaxis
 As it is highly vascular , nasal vasoconstrictor should be
applied usually topically, before instrumentation of nose to avoid epistaxis.

9.  NASAL SEPTUM DEVIATION is common in adults therefore the more patent side
should be determined before passing instrumentation through nasal passage.
Floor: Formed by palatine process of maxilla, palatine bone
APPLIED ANATOMY:
floor of nasal cavity is almost perpendicular to the plane of face so tracheal tube
is inserted at right angle to the plane of face.
Roof: Formed cribriform plate of ethmoid bone
APPLIED ANATOMY:
 Disruption of cribriform plate leads to CSF rhinorrhea , is a contraindication for passing
nasogastric tube insertion(Ryle’s tube) and nasotracheal intubation.

10. Nerve supply-
- Olfactory nerves
- Nerves of common sensation-
Anterior ethmoidal nerve
Sphenopalatine nerve
Infraorbital nerve
- Autonomic nerves
Blood supply -
Upper part of nasal cavity :Anterior & posterior ethmoidal arteries
Lower part of nasal cavity :Sphenopalatine branch of maxillary artery
Lateral wall

11. PHARYNX
 Extends from base of skull to cricoid cartilage anteriorly and to inferior border of
sixth cervical vertebra posteriorly.
 12-14 cm long
 3.5cm wide at its base(Hyoid bone)
 1.5cm at pharyngo-esophageal junction(narrowest part of digestive tract apart
from the appendix) which is MC site for obstruction with foreign body aspiration.
 Posterior pharyngeal wall made up of buccopharyngeal fascia which separates
pharyngeal structures from retropharyngeal space. Improper placement of gastric or
tracheal tube can result in laceration of fascia
 The wall of pharynx contain two layer of muscle Circular(external)
Longitudinal(internal)

12.  Internal layer muscles- Stylopharyngeus, salpingopharyngeus , palatopharyngeus
They elevate the pharynx and shortens the larynx during deglutition.
 External layer muscles- Superior constrictor, middle constrictor, inferior constrictor
They advance the food from oropharynx to esophagus.
 Nerve supply: Internal layer by Glossopharyngeal nerve.
External layer innervated by pharyngeal plexus formed by-
*Vagus
*Glossopharyngeal
*External branch of superior laryngeal nerve
The inferior constrictor also innervated by recurrent laryngeal N.
 The pharynx divided in to –Nasopharynx
Oropharynx
Laryngopharynx/Hypopharynx

13. NASOPHARYNX
 It extends from posterior nasal aperture to the posterior pharyngeal wall above the
soft palate.
 Consists of nasal cavity, septum, turbinates, and adenoids.
APPLIED ANATOMY:
 Ends at soft palate , this area is called velopharynx & is common site for airway
obstruction in both awake and anaesthetized patient.
 Roof of nasopharynx forms an acute angle with the posterior pharyngeal wall –while
passing any tube through the nose into the oropharynx a simple maneuver of
extension of head will straighten out this angle & facilitates the passage of tube.
 Adenoids are located in its roof which are frequently hypertrophied during childhood
& may cause obstruction or hemorrhage while passing any tube through the nose.

14. OROPHARYNX
 Extends from soft palate to superior edge of epiglottis.
 It includes tonsils, uvula, and the epiglottis.
 Most important area in terms of airway obstruction & management as it is made of
collapsible soft tissue all around.
VALLECULA- The entire space between epiglottis & base of
tongue & has paired depression of the two sides of median
glossoepiglottic fold.
APPLIED ANATOMY:
 Laryngoscope blade tip lies in vallecula during classical Macintosh laryngoscopy.
 The vallecula is a common site of impaction of foreign bodies, such as fish bones, in
the upper airway.

15. WALDEYER’S RING
 The ring includes masses of lymphoid tissue or tonsils,
including – Two large palatine tonsils
Lingual tonsil
Eustachian tubal tonsils
Nasopharyngeal Tonsil(Adenoids)
 Patient with Enlarge tonsils (kissing tonsil) are more prone to difficult
ventilation when put to sleep. So avoid sedative premedication.
 The lingual tonsils are located between the base of the tongue and the epiglottis.
 Lingual tonsillar hypertrophy, which is usually asymptomatic, has been reported as
a cause of unanticipated difficult intubation and fatal upper airway obstruction.

16. LARYNGOPHARYNX
Extends from superior border of epiglottis to inferior border of cricoid cartilage.
APPLIED ANATOMY:
1.Pyriform fossa (sinus)-
 Internal laryngeal nerve runs submucosally in the lateral wall of
the pyriform sinus and thus is easily accessible for local anesthesia.
2. Postcricoid area-
 It is the part of the anterior wall of laryngopharynx between the
upper and lower borders of cricoid lamina. It is a common site
for carcinoma in females suffering from Plummer–Vinson synd.
Pharynx open from behind

17. LARYNX
SITUATION AND EXTENT-
 It lies in the midline of neck opposite C3 to C6 vertebra in adult & C1 to C4 vertebra
in children.
 It extends from the upper border of epiglottis to lower border of cricoid cartilage.
MEASUREMENT- MALE FEMALE
Vertical Length 44mm 41mm
Transverse diameter 36mm 36mm
A P diameter 43mm 26mm
 The glottis is the narrowest part in adult.
 The subglottis (cricoid ring) narrowest part in children up to the age of 5yrs.
That’ s why in children uncuffed endotracheal tube can be used.

18. SKELETON OF LARYNX-
 Larynx consists of 3 paired cartilages and 3 unpaired cartilages.
 Unpaired cartilages- Thyroid
Cricoid
Epiglottis
 Paired cartilages- Arytenoid
Corniculate
Cuneiform
 Thyroid cartilage is the largest cartilage.
 Cricoid cartilage is the only complete
cartilaginous ring in airway.

19. THYROID CARTILAGE
 Longest laryngeal cartilage & largest structure in larynx.
 Consist of 2 quadrilateral laminae, fuse along their
inferior two third anteriorly to form laryngeal prominence.
 Vocal cords are attached to its middle.
 Thyroid angle in female 1200 and in male 900
 "BURP“TECHNIQUE-
(Backwards Upwards Rightwards Pressure) maneuver,
which is used to improve the view of the glottis during
laryngoscopy and tracheal intubation. It requires a
clinician to apply pressure on the thyroid cartilage
posteriorly, then cephalad (upwards) and, finally, laterally
towards the patient's right.

20. CRICOID CARTILAGE
 Cricoid doesn’t allow space for edema to spread outwards and thus any injury in this
area can worsen quickly.
SELLICK’S MANEAUVER
In patients who are at risk of gastric aspiration,
during airway management downward pressure
over cricoid cartilage will prevent passive regurgitation
without subsequent airway obstruction.
This is known as Sellick’s Maneuver.

21. EPIGLOTTIS
 It is leaf like elastic cartilage forming anterior wall of laryngeal inlet.
Free end Attached part
Broad and notched in Long and narrow
midline connect to thyroepiglottic
ligament
 Sides: Attached to arytenoids by aryepiglottic fold.
ARYTENOIDS – Pyramidal in shape
CORNICULATES – lie at apex of arytenoids.
CUNEIFORM - rod shaped and lie in front of corniculate cartilages.

22. LARYNGEAL CAVITY
 Extends from laryngeal inlet down to lower border of cricoid cartilage
where it continues in to trachea.
 By paired upper and lower mucosal fold projecting into
lumen laryngeal cavity divided into-
UPPER(SUPRAGLOTTIC)
MIDDLE(GLOTTIC)
LOWER(SUBGLOTTIC)
 Upper fold: Vestibular fold(FALSE VOCAL CORD)
Pink in color
 Lower fold: Vocal fold(TRUE VOCAL CORD)
Pearly white in color

23. GLOTTIS
 It is the narrowest part of the laryngeal cavity.
 It is elongated space b/w vocal cord anteriorly and
Vocal process and base of arytenoid posteriorly.
 In adult.
A-P length: - Male –24mm
Female –16mm
 It is divided into two part–
 I –Anterior inter-membranous part(2/3) –
Situated between the two vocal fold.
 II-Posterior inter-cartilaginous part(1/3) –
Passes between the two arytenoids cartilage.

24. MUSCLES OF LARYNX
 EXTRINSIC MUSCLE – which attaches larynx to the surrounding structures
 INTRINSIC MUSCLE -- which attaches laryngeal cartilages to each other and affect
glottic movement
EXTRINSIC MUSCLE
 SUPRAHYOID MUSCLE – Attaches larynx to the hyoid bones & elevate the larynx
e.g.– Geniohyoid, Stylohyoid, Mylohyoid, Diagastric, Thyrohyoid, Stylopharyngeus.
 INFRAHYOID MUSCLE – Strap muscle, in addition to lowering of larynx, can modify
the internal relationship of laryngeal cartilage & folds to one another.
e.g.. –Sternohyoid , Sternothyroid , Omohyoid.

25. INTRINSIC MUSCLE
I –ACTING ON VOCAL CORD
Abductor – Posterior cricoarytenoid
Adductor – Lateral cricoarytenoid, Transverse &
oblique arytenoid
Tensor (Elongation) – Cricothyroid, Partly Vocalis
Relaxer (Shortening) – Thyroarytenoid, Partly Vocalis
II –ACTING ON LARYNGEAL INLET
Openers – Thyroepiglottic , Thyroarytenoid
Closer – Aryepiglottic , Oblique arytenoid

26. NERVE SUPPLY OF LARYNX
 SENSORY –Above the vocal cord– Internal laryngeal nerve (branch of SLN)
Below the vocal cord- Recurrent laryngeal nerve
 MOTOR – All intrinsic muscle of the larynx are
supplied by RLN except cricothyroid
which is supplied by external laryngeal
nerve which is a branch of SLN.
Both SLN & RLN are branches of vagus nerve

27. ARTERIAL SUPPLY & VENOUS DRAINAGE
ABOVE THE VC - Superior laryngeal artery, a branch of superior thyroid artery.
Superior laryngeal vein, drains into superior thyroid vein
BELOW THE VC – Inferior laryngeal artery, a branch of inferior thyroid artery.
Inferior laryngeal vein, drains into Inferior thyroid vein.
LYMPHATIC DRAINAGE
ABOVE THE VC - Pre laryngeal & Jugulo–Digastric LN.
BELOW THE VC – Pre tracheal & Para tracheal LN.

28. SENSORY NERVE SUPPLY OF AIRWAY
*The sensory supply to the upper airway is derived from the
cranial nerves.
*The mucous membranes of the nose are innervated by the
ophthalmic division (V1) of the trigeminal nerve anteriorly
(anterior ethmoidal nerve) and by the maxillary division (V2)
posteriorly (sphenopalatine nerves).
*The palatine nerves provide sensory fibers from the
trigeminal nerve (V2) to the superior and inferior surfaces of
the hard and soft palate.
*The lingual nerve (a branch of the mandibular division [V3] of
the trigeminal nerve) and the glossopharyngeal nerve (cranial
nerve IX) provide general sensation to the anterior two-thirds
and posterior one-third of the tongue, respectively.

29. APPLIED ANATOMY:
 THE EFFECTS OF LARYNGEAL NERVE INJURY ON VOICE
 In complete paralysis of both recurrent and SLN the cords are held
in mid position(cadaveric position)
 Cords are also in cadaveric position during GA with muscle relaxants.
RLN Injury

30. AWAKE INTUBATION
 Glossopharyngeal nerve block - supplying posterior third of tongue & oropharynx.
 bilateral superior laryngeal nerve block – sensory supply to upper part of larynx
 Trans-tracheal (translaryngeal) block – supply trachea and vocal cords.

31. PERCUTANEOUS AIRWAY
 Percutaneous (invasive) airways are indicated as a rescue technique when attempts
at establishing a noninvasive airway fail.
 Invasive airway access include- Trans- tracheal jet ventilation (TTJV)
Cricothyrotomy
Tracheostomy
TRANSTRACHEAL JET VENTILATION
 The ASA “Difficult Airway Algorithm” lists TTJV as an emergent invasive technique to
be used in patients who cannot be conventionally ventilated or intubated.
 It is an invasive technique, and its primary use is as an emergency airway.
 It is a life-saving procedure that can provide adequate, temporary oxygenation and
ventilation with less training and complications than a surgical airway.

32.  Inspiration during TTJV is achieved by insufflation of pressurized oxygen through a
cannula placed by needle cricothyrotomy.
 Expiration is passive as a result of the elastic recoil of the lungs and the chest wall.
 Expiration occurs through the glottis and depends on a non obstructed upper airway,
which is imperative to avoid barotrauma and resulting pneumothorax.
 The egress of air through the glottic aperture can also provide bubbles to facilitate
the placement of an ETT.
 CONTRAINDICATION-
ABSOLUTE- Damage to the cricoid cartilage or larynx ,
complete upper airway obstruction.
RELATIVE- coagulopathy, obstructive pulmonary disease, and distorted anatomy in
which catheter placement might be difficult.

33.  Typically, a 12- to 16-gauge kink-resistant catheter is used for TTJV.
 A coil-reinforced 6 Fr catheter is specifically designed for TTJV to prevent kinking,
and its Teflon coating facilitates its passage through the CTM into the trachea.
 Confirmation of proper intratracheal placement of the catheter by testing for
aspiration of air is imperative before initiating jet ventilation.
 The minimum pressure required to drive a jet ventilator is 15 psi.
 COMPLICATIONS - Barotrauma with resulting pneumothorax
Subcutaneous or mediastinal emphysema
Hemorrhage, aspiration, and perforation of the posterior wall of
the trachea or esophagus.

34. CRICOTHYROTOMY
 Cricothyrotomy is an invasive technique that provides access to the airway in
situations when either noninvasive maneuvers have failed or when it is clinically
indicated as a primary plan to secure the airway.
 Cricothyrotomy is not considered a permanent airway, and, after placement, plans
should be made for either the removal of the cricothyrotomy catheter or conversion
to a formal tracheostomy.
 CONTRAINDICATION-
1. In children younger than 6 years of age, the cricoid cartilage is the narrowest
portion of the airway and the isthmus of the thyroid gland typically reaches the
level of the CTM; therefore surgical cricothyrotomy is contraindicated.
2. Laryngeal fractures, laryngeal neoplasm, subglottic stenosis, coagulopathy,
and distorted or unidentifiable neck anatomy.

35. Anatomical consideration of cricothyrotomy-
Cricothyroid membrane is located between thyroid and
cricoid cartilage.It is about 9 mm vertically and 30 mm
horizontally in an adult and is the site of incision for
Cricothyrotomy.

36.  Technique of cricothyrotomy – 3 main approaches
Needle cricothyrotomy Percutaneous cricothyrotomy Surgical cricothyrotomy
using Seldinger technique
Needle cricothyrotomy –
STEPS:-
 Position the patient, prepare a sterile field, including cleansing with antiseptic solution.
 Identify landmark. Palpate the thyroid cartilage and cricoid cartilage and the area
between them, which is cricothyroid space that contains membrane.
 With non dominant hand, stabilize the area using the first and third digit to either side
of thyroid cartilage, leaving the index finger to palpate the membrane.

37.  With the dominant hand, insert angiographic catheter or
Patil’s cannula, attached to syringe filled with normal
saline, into cricothyroid membrane, directing it caudally at
a 45 degree angle.
 As the needle is advanced, apply negative pressure to
syringe. A distinct pop is felt as the needle traverses
membrane and enters trachea. Air bubbles will appear in
the fluid filled syringe.
 Withdraw needle with syringe and leave angiographic
catheter in place.

38. Percutaneous cricothyrotomy (seldinger) technique –
 Because of the location of the cricothyroid artery and the proximity
of the CTM to the vocal folds, puncture or incision of the CTM
should be made in the lower third of the membrane and directed
posteriorly.
 The basis for this procedure is the insertion of an airway catheter
over a dilator that has been inserted over a guidewire.
 The patient’s neck is extended, and the cricothyroid groove is identified.
 If landmarks are difficult to identify , then ultrasound guidance may be used.
 A 1- to 1.5-cm vertical incision is made through the skin overlying the CTM.

39.  An 18-gauge needle-catheter attached to a fluid filled syringe is passed through the incision at a
45-degree angle in the caudal direction with continuous aspiration.
Aspiration of free air confirms passage through the CTM.
 The catheter is advanced over the needle into the trachea. The needle is removed, and the
catheter is left in place. The guidewire is inserted caudally to a depth of approximately 2 to 3 cm.
The catheter is removed, and the curved dilator with the airway cannula is threaded over the
guidewire.
 The dilator and cannula unit is advanced through the CTM while maintaining control of the
guidewire. The dilator and guidewire are removed together while the cannula remains in place.
The cuff is inflated, and ventilation is attempted.
 Proper placement is confirmed by capnography, and the airway cannula is secured in place.

40. Surgical cricothyrotomy
COMPLICATIONS - Hemorrhage, injury to the posterior tracheal wall or esophagus,
vocal cord injury, laceration of the thyroid gland, and improper
insertion of the cannula, tracheal stenosis.

41. COMPARISION BETWEEN PEDIATRIC & ADULT AIRWAY
S.NO. PAEDIATRIC ADULT
1. Head size is large prominent occiput.
Intubation done in neutral position.
Flat occiput.
2. -Narrow nares and nasal breathers.
-Angle of jaw more obtuse.
-Large tongue, tend to fall backward
under anesthesia.
3.Larynx
Size and
shape
Smaller, funnel shaped with narrowest part
below vocal cords within cricoid (subglottic).
Larger cylindrical, narrowest
part at glottis.
Location C1 to c4 C3 to c6
Epiglottis Longer , floppy ,U shaped, protruding &
narrower, epiglottis is more of an acute angle.
Flat and broad and its axis is
parallel to trachea.
Applied
anatomy
Leaf like and floppy epiglottis in children
necessitating the use of straight blade
laryngoscope.

42. LARYNGOSCOPIC ANATOMY- To view larynx
Oral, pharyngeal and laryngeal axes must be in one
plane plane

43. TRACHEA
 Starts from cricoid ring(C6) to carina(T5)
 Length 10-16 cm
 External diameter of trachea Male: 2.3cm coronally
1.8cm sagitally
Female: 2cm coronally
1.4cm sagitally
 Internal diameter 1.2 cm
 It s flattened posteriorly and contains 16-20 horse shoe shaped cartilaginous rings
 The posterior part of trachea void of cartilage, consists of membrane of smooth
muscle and fibro elastic tissue joining the ends of cartilage.

44.  The rings are incomplete to allow the trachea to collapses lightly so that food can
pass down the esophagus.
 At the 6th ring trachea becomes intrathoracic
 Divided into right and left main bronchus at carina
 Distance from upper incisor to carina 28-30cm
CARINA
 Ridge on internal aspect of last tracheal cartilage
 Point where trachea branches (when alive and standing is at T5)
 Mucosa highly sensitive to irritants: cough reflex

45. VARIOUS MEAN DISTANCES IN ADULTS OF INTEREST TO THE
ANAESTHESIOLOGIST:
1.Mean distance from lips to carina:
Male 28.5cm
Female 25.2cm
2.Mean distance from base of nose to carina:
Male 31cm
Female 28.4cm
3.Mean distance from lips to vocal cords:
Male 12- 16cm
Female 10 -14cm
4.Mean distance from upper edge of larynx to lower edge of cricoid: 4- 6cm
5.Mean length of trachea (vocal cord to carina) :Male 12- 14cm
Female10- 12cm

46. Dichotomous division starting with trachea and ending in alveolar sac:
RIGHT MAIN BRONCHUS LEFT MAIN BRONCHUS
1.Shorter(2.5cm) 1.Longer(5cm in man
4.5cm in woman)
2.Wider 2.Narrower
3.Angle with vertical 3.Angle is 45 degree
25 degree
4.Aorta arches over
the left main bronchus

47. APPLIED ANATOMY:
 Due to shorter wider and less acute angle, chances of endotracheal tube to be
positioned on right side are more.
 Foreign body aspiration:
The right main stem bronchus is wider shorter and vertically placed therefore the
posterior segment of Right Upper lobe is most susceptible to aspiration pneumonia.
 Segments AFFECTED in supine position: Right Upper lobe – Posterior segment(mostly)
 Segments involved aspiration in sitting or erect position: Basilar segment of right
Lower lobe

48. Segmental bronchi:

49. Broncho pulmonary segments:
 Broncho pulmonary segments are independent respiratory units.
 Each segment has its own separate artery and each segment has more than one vein.
 Broncho pulmonary segment is not a Broncho vascular segment because it dose not
have its own vein.
APPLIED ANATOMY:
 Usually the infection of segment remains restricted to it, although some infections like
TB may spread from one segment to another.

50. ARTERY SUPPLY OF BRONCHIAL TREE:
 Up to terminal bronchioles bronchial artery
 Beyond the terminal bronchioles pulmonary artery
NERVE SUPPLY OF BRONCHIAL TREE:
 Parasympathetic by vagus (bronchoconstriction)
 Sympathetic(T2 - T5) ( Broncho dilatation)

51. LUNGS
 Right lung weighs about 700gm
 It is about 50 - 100 gm heavier than the left lung.
 The Right lung is divided in to three lobes( Upper, Middle, Lower ) by two i.e.
oblique or major and horizontal or minor fissure
 Left lung divided in to two lobes by oblique fissure
 Upper border of lung limited up to 6cm above sternoclavicular joint.
 Lower border of lung lies on 6th rib,8th rib,10th rib on the midclavicular, midaxillary , posterior
scapular line respectably.

52. Differences between right and left lung
RIGHT LUNG LEFT LUNG
1.It has 2 fissures and 3 lobes 1.It has one fissure and 2 lobes.
2.Anterior border is straight 2.Anterior border is interrupted by
the cardiac notch
3.Larger and heavier 3.Smaller and light
4.Shorter and broader 4.Longer and narrower

53. AIRWAY ASSESSMENT
Why it is necessary??
PURPOSE -TO DIAGNOSE THE POTENTIAL FOR DIFFICULT AIRWAY FOR
 Optimal patient preparation.
 Proper selection of equipment and technique.
 Participation of personnel experienced in difficult airway management.

54. ASA DEFINITION
 DIFFICULT AIRWAY –
It is defined as “ The clinical situation in which a conventionally anesthesiologist
experiences difficulty with mask ventilation, difficulty with tracheal intubation or
both.”
 DIFFICULT MASK VENTILATION-
“The inability of a trained anesthesiologist to maintain the oxygen saturation > 90%
using a face mask for ventilation and 100% inspired oxygen, provided that the pre-
ventilation oxygen saturation level was within the normal range.
 DIFFICULT LARYNGOSCOPY-
“It is not possible to visualize any portion of vocal cord with conventional laryngoscope.
Corresponds to Cormack & Lehane’s grade IV laryngoscopic view.

55.  DIFFICULT ENDOTRACHEAL INTUBATION-
When proper insertion of Tracheal tube with conventional laryngoscopy requires
-More than 3attempts
-Longer than 10minutes
-Failure of optimal best attempt
 OPTIMAL/BEST ATTEMPT AT LARYNGOSCOPY
Can be defined as ‘Laryngoscopy performed by a reasonably experienced
laryngo-scopist with the patient in optimal sniff position having no significant muscle
tone & the laryngoscopist has an option of change of blade type & length
(one time each)’.
 INTUBATION ATTEMPT-
Defined as “Intubation activities occurring during a single continuous laryngoscopy
maneuver.”

56. History
 Patient/notes/chart/previous anesthesia records
 Surgery/burns/trauma/tumor in & around oral cavity
 Concurrent disease
 Reflux/recent meals
General examination
 Do they just look difficult?
 Recognition of anatomic factors that can cause difficult airway
Specific tests/indices
Investigations
 Nasoendoscopy
 X-ray , CT/MRI
 Flow volume loop

57. CAUSES OF DIFFICULT AIRWAY
1)FACIAL ANOMALIES - Maxillary hypoplasia (Apert syndrome, Crouzon ds)
Mandibular hypoplasia(Gierre Robin syndrome,
Treacher Collins syndrome, Goldenhar syndrome)
Mandibular hyperplasia(acromegaly)
2)TMJ PATHOLOGY - Ankylosis or reduced movement
3)MOUTH & TONGUE ANOMALY - Microstomia (burns, trauma), tumor of mouth & tongue
macroglossia (down’s syndrome, hypothyroidism)
4)TEETH PROBLEMS - Missing left upper incisors , protruding upper incisors
5)NOSE PATHOLOGY - Hypertrophied turbinate , polyps , gliomas , foreign bodies , DNS
6)PALATE PATHOLOGY - Narrow arched palate , large cleft palate
7)PHARYNX PATHOLOGY - Hypertrophied tonsils & adenoid , tumors, abscess
(retropharyngeal / parapharyngeal abscess)

58. 8)LARYNX PATHOLOGY – Epiglotitis , laryngomalacia , foreign body, papillomas,
congenital stenosis, edema
9)TRACHEAL PATHOLOGY – Tracheitis , tracheoesophageal fistula, tracheal stenosis &
webbing, foreign body , tracheomalacia
10)BROCHIAL TREE PATHOLOGY - Mediastinal mass, foreign body aspiration,
bronchial tumors
11)NECK– Large goiter , skin contracture, ankylosing spondylitis
12)SPINE- Limitation of movement( congenital Klippel-Feil syndrome,
Acquired - surgical fusion , fracture of cervical vertebrae) ;
cervical spine instability (down’s syndrome)

59. How do we assess??
The airway may be assessed for difficult airway using :-
 Individual indices
 Group indices(with and without scoring)
 Mask ventilation precedes laryngoscopy, which in turn followed by, intubation.
So the assessment should be in a systemic manner.

60. Predictors for difficult mask ventilation
INDIVIDUAL INDICES GROUP INDICES
INDIVIDUAL INDICES
 Presence of beard – Difficulty in creating an effective seal by mask leading to
loss of ventilated volume.
 Obesity - Large body mass index(>26kg/m2 )
 Abnormality of teeth – Irregular teeth, artificial denture, edentulous
 Elderly patient - >55 years
 Snorers
 Hair bun
 Jewelry and facial piercing

61. GROUP INDICES
(OBESE) (MONAS)
 Obese (BMI > 26 kg/m2) This is identical to BONES, except M
 Bearded Mask seal difficult due to receding mandible
 Elderly (older than 55 y) syndrome with facial abnormalities, burn,
 Snorers stricture, etc.
 Edentulous Obesity (BMI >26 kg/m2), upper airway
(=BONES) Obstruction
Patient having ≥2 of the predictors likely No teeth
to have difficult mask ventilation Advanced age
Snorers

62. Predictors for difficult laryngoscopy and tracheal intubation
INDIVIDUAL INDICES GROUP INDICES
 Physical examination indices - Bellhouse’s criteria
 Radiological indices - Wilson’s scoring system
 Advanced indices - Benumof’s 11 parameter analysis
- Saghei & safavi test
- Lemon assessment
- Arne’s simplified score method
- Magboul’s 4 M’s
- 4 D’s

63. PHYSICAL EXAMINATION INDICES:
(A) ASSESSMENT OF CERVICAL & ATLANTO-OCCIPITAL JOINT FUNCTION:
 DIRECT ASSESSMENT –
Assess the neck movement by asking the patient to touch his manubrium sternii
with his chin. If done this assures neck flexion of 25-30°.
Then ask the patient to look at ceiling without raising eyebows to test a-o joint
extension
GRADE 3 & 4
INDICATE DIFFICULT
LARYNGOSCOPY
Grade Reduction of A-O
Extension
1 None
2 1/3rd reduction
3 2/3rd reduction
4 Complete reduction

64. Warning sign of DELIKAN:
Place the index finger of left hand, one underneath the chin and index finger of right
hand under the inferior occipital prominence with the head in neutral position.
The patient is asked to fully extend the head on neck. If the finger under the chin is
seen to be higher than the other, there would appear to be no difficulty with
intubation. If level of both fingers remains same or the chin finger remains lower than
the other, increased difficulty is predicted.

65.  INDIRECT ASSESSMENT –
PRAYER SIGN
A positive "prayer sign" can be elicited on examination
with the patient unable to approximate the palmar surfaces
of the phalangeal joints while pressing their hands together.
Seen in Diabetes
This represents:-
cervical spine immobility and the potential for a difficult endotracheal intubation.

66. Palm Print test
 The palm and fingers of the dominant hand of the patient is painted with black
writing ink using a brush.
 The patient then presses the hand firmly against a white sheet of paper on a hard
surface.
 Scoring is done as:
Grade 0 -All phalangeal are as visible.
Grade 1 -Deficiency in the inter-phalangeal areas of 4th and/or 5th digit.
Grade2 -Deficiency in the inter-phalangeal areas of 2nd to 5th digit.
Grade 3 -Only the tips of digits seen.
 Predictor of Difficult Airway in DM

67. (B) ASSESSMENT OF TEMPORO-MANDIBULAR JOINT FUNCTION:
TMJ exhibits 2 function -
1.Rotation of the condyle in the synovial cavity.
2.Forward displacement of the condyle.
First movement is responsible for 2-3cm mouth opening & the second
is responsible for further 2-3cm mouth opening.

68. CALDER TESTSUBLUXATION 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 behind the ear
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

69.  UPPER LIP BITE /CATCH TEST
Class I: Lower incisors can bite the upper lip above vermilion line
Class II: Lower incisors can bite the upper lip below vermilion line
Class III: Lower incisors cannot bite the upper lip
Significance
 Assessment of mandibular movement and
dental architecture
 Less inter observer variability

70.  SYMMETRY OF UPPER AND LOWER FACE
The upper face should be measured from
bridge of the nose to just below the nasal
septa at the upper lip while the lower face is
measured from just below nasal septa to chin.
If the lower face is longer than the upper part of face,
then some degree of difficulty in lining up structures
should be anticipated.

71. (C) ASSESSMENT OF MANDIBULAR SPACE:
This space determines how easily the laryngeal and pharyngeal axis will fall in line
when the a-o joint is extended
 THYROMENTAL DISTANCE/ PATIL’S TEST
Measure from upper edge of thyroid cartilage to chin with the head fully extended
>6.5cm No Problem with Laryngoscopy & Intubation
6-6.5cm Difficult Laryngoscopy & Intubation
<6cm Laryngoscopy may be Impossible

72.  Ratio of patient height to thyromental distance (RHTMD)
Useful bedside screening test
RHTMD > 23.5 –very sensitive predictor of difficult laryngoscopy
 HYOMENTAL DISTANCE
Distance between mentum and hyoid bone
Grade I: >6cm
Grade II: 4 –6cm
Grade III : < 4cm (Impossible laryngoscopy
& Intubation)

73.  INTER-INCISOR GAP
- Inter-incisor distance with maximal mouth opening
- Normal value >5cm/ admits 3 fingers.
Significance:
Positive results: Easy insertion of a 3 cm deep flange of the laryngoscope blade
<3cm: Difficult laryngoscopy
<2cm: Difficult LMA insertion
Affected by TMJ and upper cervical spine mobility
 STERNOMENTAL DISTANCE (SAVVA TEST)
- Distance from the upper border of the manubrium to the tip of mentum , neck fully
extended ,mouth closed
- Minimal acceptable value - 12.5cm
- Single best predictor of difficult laryngoscopy and intubation (Has high sensitivity &
specificity)

74. (D) TEST FOR ASSESSING ADEQUACY OF THE OROPHARYNX FOR
LARYNGOSCOPY AND INTUBATION
 Mallampati grading (samsoon and young’s modification)
 Narrowness and arching of the hard palate – a narrow , high arched palate offer very
little space for laryngoscopy and endotracheal intubation.
MODIFIED MALLAMPATI GRADING
 Suggest optimal tongue size in relation to oropharyngeal cavity permitting easy
laryngoscopy.
 Indicate amount of space with in the oral cavity to accommodate the laryngoscope &
ETT.

75.  Assessed when the patient is - Seated
- Upright with head protruding forward
- Mouth open
- Tongue protruded as much as possible
- No phonation.
The observer’s eye At the level of patient’s
open mouth
 Higher scores poor visibility of the
oropharyngeal structures Large
tongue relative to the size of the
oropharyngeal space Difficult
laryngoscopy
Grade 0: Epiglottis seen on mouth opening and tongue protrusion

76. (E) ASSESSMENT FOR QUALITY OF GLOTTIC VIEWING DURING
LARYNGOSCOPY
 Indirect mirror laryngoscopic view- closely relates with cormack & lehane grading
 Direct laryngoscopy ‘awake look’-cormack and lehane grading
 Grading ease of intubation
 POGO (percentage of glottic opening)scoring

77. CORMACK –LEHANE GRADING
Grading at direct laryngoscopy
Grade1: Full exposure of glottis (anterior + posterior commissure)
Grade2: Anterior commissure not visualized
Grade3: Epiglottis only
Grade4: No glottic structure visible.
Grade I = success & ease of intubation

78. GRADING EASE OF INTUBATION
 Grade 1- Extrinsic manipulation of larynx not required
 Grade 2- Extrinsic manipulation of larynx required
 Grade 3- Intubation possible with stylet guided
 Grade 4- Failed intubation
POGO SCORING
 Percentage of glottic opening during direct laryngoscopy
 100%- entire glottis structures visible
 33%- only lower third of vocal cord & arytenoid visible
 0% - no glottic structure visible
USEFUL WHEN NEW INTUBATING DEVICE TO RECORD EXACT % OF GLOTTIC OPENING
THAT CAN BE VISUALISED BY THIS DEVICE

79. RADIOLOGICAL INDICES
1. X-Ray neck (lateral view) :
 Occiput and 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.
2. CT Scan:
 Tumors of floor of mouth, pharynx, larynx
 Cervical spine trauma, inflammation
 Mediastinal mass
3. Helical CT (3D-reconstruction):
 Exact location and degree of airway compression

80. ADVANCED INDICES
 Flow volume loop
 Acoustic response measurement
 Ultrasound guided
 CT / MRI
 Flexible bronchoscope

81. GROUP INDICES
BELHOUSE’S CRITERIA:
Three parameter criteria for predicting difficult tracheal intubation are
as follow-
 Restricted atlanto-occipital joint extension (less than 35 degree)
 Reduced mandibular space
 Enlarged tongue( versus pharyngeal ) size

82. WILSON’S SCORING SYSTEM:
score <=5 easy laryngoscopy
score 6- 7 moderate difficulty
score 8–10 severe difficulty
in laryngoscopy
Parameter 0 1 2
Weight <90 90-110 >110
Head and neck
movement
>90 =90 <90
Jaw movement
(inter incisor gap)
>5 cm = 5 cm <5 cm
Receding
mandible
none moderate severe
Buck teeth none moderate severe

83. BENUMOF’S 11 PARAMETER ANALYSIS:
Parameter Minimal acceptable value Significance
Inter- incisor gap >3cm Easy insertion of laryngoscope blade
Buck Teeth No overriding Cause blade to enter cephalad
Length of upper incisor Short incisors (<1.5cm) Long prevent alignment of OPA
Voluntary protrusion of
mandibular teeth anterior to
maxillary teeth
Mandibular teeth can be
protruded beyond the
maxillary teeth
Suggest optimal TMJ function, both
rotatory and sliding
Mallampati class Class 2 or less Easy laryngoscopy
Palate configuration No arching or narrowness Reduce space for laryngoscope blade
Thyromental distance >5cm/>3 finger breadth Optimally placed larynx
Mandibular space Soft to palpation Allows easy tongue compressibility
Neck length Qualitative Thick short neck decrease
Neck thickness Qualitative Not well significant
Head /neck movement Normal range 3 axes aligned
4-2-2-3 rule
4 for tooth
2 for inside
of mouth
2 for
mandibular
space
3 for neck
examination

84. SAGHEI & SAFAVI’S TEST:
 Weight >80kg
 Tongue protrusion <3.2 cm
 Mouth opening <5 cm
 Upper incisor length >1.5 cm
 Mallampati class >1
 Head extension <70 degree
Any 3 indices if present Prolonged laryngoscopy

85. ARNE’S SIMPLIFIED SCORE MODEL:
Risk factor Score
Previous knowledge of difficult intubation
No
Yes
0
10
Diseases associated with difficult intubation
No
Yes
0
5
Clinical symptoms of airway pathology
No
Yes
0
3
Inter incisor gap (IG) and mandible subluxation (ML)
IG > 5 cm or ML >0
IG <5- 3.5 and ML =0
IG<3.5 cm and ML<0
0
3
13
Thyromental distance
>6.5cm
< 6.5cm
0
4

86. Maximum range of head & neck movement
More than 1000
About 900 (+/-100)
Less than 800
0
2
5
Mallampati score
Class 1
Class 2
Class 3
Class 4
0
2
6
8
Total possible………….. 48
Score of >11 is predictive of difficult tracheal intubation

87. LEMON TRIAL:
Represents 5 simple rapid assessment methods on uncooperative & cooperative
patient.
 Look (for anatomic feature) Examination (of airway anatomy)
Facial trauma 3-3-2
Large incisors *Inter incisor gap – mouth opens at least
Beard 3 fingers breadth.
Large tongue *Hyomental distance – 3 fingers breadth
Facial hairs *Thyroid to floor of mouth distance
Facial/oral swelling – 2 finger breadth

88.  Mallampati grading
 Obstruction
Laryngoscopy or intubation may be more difficult in the presence of an obstruction
–LOCATION
–FIXITY
–PROGRESSION
 Neck mobility
•Normal
•Neck extension >80-85
•Flexion > 25-30
•Rotation>70-75
Assess All 3 ANGLES

89. MAGBOUL’S 4 M’s:
For Intubation remember the 4(M & M’s) with (STOP) sign
 Mallampati
 Measurement
 Movement
 Malformation & STOP
M =Malformation of the skull, teeth, obstruction, & Pathology (the Macros and
Micros). We can memorize them with the word (STOP)
 S= Skull (Hydro and Microcephalus)
 T= Teeth (Buck, protruded, & loose teeth, macro and micro mandibles)
 O= Obstruction (due to obesity, short Bull Neck and swellings around the head and
neck)
 P= Pathology (Craniofacial abnormalities & Syndromes: Treacher Collins,
Goldenhar's, Pierre Robin, Waardenburg syndromes) .

90. Score 1 2 3 4
Mallampati grade 1 grade 2 grade3 grade4
Measurement 3 mouth open 3 thyromental 2 hyomental 1 subluxation
Movement Left Right Flexion Extension
Malformation S T O P
Total 4 4 4 4
Score 8 or higher Difficult intubation

91. FOUR D’s:
The following Four D's also suggest a difficult airway:
 Dentition (prominent upper incisors, receding chin)
 Distortion (oedema, blood, vomits, tumor, infection)
 Disproportion (short chin-to-larynx distance, bull neck, large tongue, small mouth)
 Dysmobility (TMJ and cervical spine)

92. 1 – 2 – 3 FINGER RAPID ASSESSMENT TEST
 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 15 sec to assess
the TMJ function, mouth opening and hyomental distance. Significant difficulty in 2
or more of these components requires detailed examination.

93. THANK YOU