predictors of airway in pediatric anesthesia podgorica 2014

Marijana KarišikHead of Department of AnesthesiologyInstitute for children diseases Clinical Center of Montenegro, Podgorica

PREDICTORS OF AIRWAY IN PEDIATRIC ANESTHESIA

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



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.

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


Pierre-Robin sy: Micrognathia, macroglossia, cleft soft palate

Treacher-Collins sy: Auricular and ocular defects, malar andmandibular hypoplasia

Goldenhar’s sy:Auricular and ocular defects, malar andmandibular hypolasia

Down’s sy: Poorly developed or absent bridge of thenose, macroglossia

Kippel-Feil sy: Congenital fusion of a variablenumber of cervical vertebrae, restriction of neck movement


Congenital airway-compromising conditions in children

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


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 stridorshould alert the anesthesiologist, as these are often associated with difficult airways in pediatric population


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 SystemClass 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.


Cormack and Lehane Grading SystemThe Cormack and Lehane grading system is based on one’s ability to visualize certain structuresupon 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.


Thyromental DistanceThe 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.


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


Atlanto-Occipital JointJoint 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.


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)


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


When work is a pleasure, life is a joy!Maxim Gorky

predictors of airway in pediatric anesthesia podgorica 2014

Health & Medicine

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