This document discusses predictors of difficult airways in pediatric anesthesia. It begins by defining a difficult airway as one where a trained anesthesiologist has difficulty with mask ventilation or tracheal intubation. Several tools for assessing airway difficulty in adults are described, including Mallampati classification and Cormack-Lehane grading, as well as adaptations for pediatric patients. Specific anatomic features that can indicate an difficult airway are outlined. The document concludes that age, interincisor gap, neck circumference, and sternomental distance can predict difficult mask ventilation, while age, best oropharyngeal view, neck circumference, and thyromental distance predict difficult laryngoscopy and intubation.

1. Marijana Karišik
Head of Department of Anesthesiology
Institute for children diseases
Clinical Center of Montenegro, Podgorica
PREDICTORS OF AIRWAY IN
PEDIATRIC ANESTHESIA

2.  In pediatric anesthesia 13% of reported respiratory
problems are related with the difficulty to intubate,
and the literature demonstrates the importance of
predicting the possibility of difficult airway
PREDICTORS OF AIRWAY IN PEDIATRIC ANESTHESIA

3. PREDICTORS OF AIRWAY IN PEDIATRIC ANESTHESIA
 American Society of Anesthesiologists defines a difficult
airway as “the clinical situation in which a conventionally
trained anesthesiologist experiences difficulty with mask
ventilation, tracheal intubation or both”
 A successful intubation is easier to define.Induction time and
age group were both found to be predictors of successful
intubation. The induction time to achieve 80% successful
intubation was 137 seconds for ages 1-4, and 187 seconds for
ages 4–8. Politis et al. Anaesthesia and Analgesia 2002.

4.  Predictive tests of difficult intubation were
developed and evaluated in adults
 The lack of studies in children and the possibility of
difficult intubation in pediatric patients, apparently
without anatomic deformities indicate the need of
studies in this field
PREDICTORS OF AIRWAY IN PEDIATRIC ANESTHESIA

5. Pierre-Robin sy: Micrognathia,
macroglossia, cleft soft palate
Treacher-Collins sy: Auricular
and ocular defects, malar and
mandibular hypoplasia
Goldenhar’s sy:Auricular and
ocular defects, malar and
mandibular hypolasia
Down’s sy: Poorly developed
or absent bridge of the
nose, macroglossia
Kippel-Feil sy: Congenital
fusion of a variable
number of cervical vertebrae,
restriction of neck movement
PREDICTORS OF AIRWAY IN PEDIATRIC ANESTHESIA
Congenital airway-compromising conditions in children

6. Supraglottis Laryngeal
oedema
Subglottic Laryngeal
oedema - Croup
Abscess (intraoral,
Distortion of the airway
and trismus
retropharygeal)
Ludwig’s angina, Distortion of
the airway and trismus
Acromegaly, Macroglossia
Burns and Trauma,
Oedema of airway
Acquired airway-compromising conditions in children
PREDICTORS OF AIRWAY IN PEDIATRIC ANESTHESIA

7.  Preoperative evaluation with comprehensive history and
physical examination help identify potentially difficult airway
 Signs:
– snoring and sleep apnea
– history of problems during previous anesthesia
– presence of hypoxemia (pulse oximetry, cyanosis)
– neck mobility,
– mandibular hypoplasia
– limited mouth opening
– facial asymmetry including abnormalities of the ear and stridor
should alert the anesthesiologist, as these are often associated with difficult
airways in pediatric population
PREDICTORS OF AIRWAY IN PEDIATRIC ANESTHESIA

8.  The main adult airway assessment tool Mallampati's classification will be described, as
pediatric tools, also, but Mallampati test may not always be performed in pediatric patients,
because they are not cooperative as adults are
 Modified Mallampati classification is to assess the structures with the patient sitting upright,
with the tongue out, and no vocalization
 The best oropharyngeal view (BOV) is the method of assessment similar to assessing MMP,
mouth wide open but without tongue protrusion and better airway assessment tool than
MMP classification in children
Mallampati Classification System
Class I: soft palate, tonsillar fauces, tonsillar pillars, and uvula visualized - “easy” intubation.
Class II: hard and soft palate, tonsillar fauces, and uvula visualized - “mildly difficult” intubation.
Class III: hard and soft palate, base of uvula visualized - “much more difficult” intubation.
Class IV: soft palate not visible - “near impossible” intubation.
PREDICTORS OF AIRWAY IN PEDIATRIC ANESTHESIA

9.  Cormack and Lehane Grading System
The Cormack and Lehane grading system is based on one’s ability to visualize certain structures
upon direct laryngoscopy..
Grade I: All or most of the glottis is seen.
Grade II: Only the posterior portion of the glottis can be seen. Grade II may not be considered “difficult”
as defined by ASA if some part of the vocal cords is visible.
Grade III: Only the epiglottis can be seen. Grade III is considered difficult as defined by the ASA.
Grade IV: Neither the epiglottis nor the glottis can be seen. Grade IV is considered difficult as defined by
the ASA.
PREDICTORS OF AIRWAY IN PEDIATRIC ANESTHESIA

10.  Thyromental Distance
The thyromental distance (TMD) is the distance from the lower mandible to the thyroid
notch.The measurement is performed with the adult patient’s head fully extended. It helps
determine how readily the laryngeal axis will fall in line with the pharyngeal axis when the
atlanto-occipital(A/O) joint is extended. If the distance is short (less than 3 children's finger
breadths), it is difficult to achieve alignment of the airway axes, and less space is available
for tongue displacement and difficult intubation.
PREDICTORS OF AIRWAY IN PEDIATRIC ANESTHESIA

11.  Sterno-mental distance:
The distance from the upper border of manubrium to the tip of the mandible - correlation
with Mallampati class, jaw protrusion, interincisor gap and thyromental distance. It was
measured with the head fully extended on the neck with the mouth closed. A value of less
than 6 children's finger breadths is found to predict a difficult mask ventilation
PREDICTORS OF AIRWAY IN PEDIATRIC ANESTHESIA

12.  Atlanto-Occipital Joint
Joint mobility is measured when the head is held erect and forward. Normal extension is 35
degrees. Almost all extension of the head on the neck takes place at the atlanto-occipital
(A/O) joint. Flexion of the neck should also be checked by moving the chin down to the
chest. When the A/O joint can’t be extended, attempts to do so can cause the convexity of
the cervical spine to bulge anteriorly, pushing the larynx anterior as well. It is a predictor of
difficult mask ventilation and difficult intubation.
PREDICTORS OF AIRWAY IN PEDIATRIC ANESTHESIA

13.  LEMON airway assessment method
L = Look externally (facial trauma, large incisors,large tongue)
E = Evaluate the 3-3-2 rule (interincisor distance - 3 child. finger breadths
hyoid-mental distance - 3 chil. finger breadths,
thyroid-hyoid distance - 2 chil. finger breadths)
M = Mallampati (Mallampati score > 3)
O = Obstruction (presence of any condition like epiglottitis,
peritonsillar abscess, trauma)
N = Neck mobility (limited neck mobility)
PREDICTORS OF AIRWAY IN PEDIATRIC ANESTHESIA

14. Conclusion
 Age, interincisor gap, neck circumference and sternomental distance are
predictors of difficult mask ventilation
 Age, best oropharyngeal view, neck circumference and thyromental distance are
predictors of difficult laryngoscopy with intubation
PREDICTORS OF AIRWAY IN PEDIATRIC
ANESTHESIA

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