Use of ultrasound as a tool to predict difficult intubation in pediatric patients

PRIMARYOBJECTIVE:To determine the utility of ultrasonographicmeasurements of tongue width, tongue thickness, tonsil size, hyo-mental distance andthyrohyoid distance of pediatric patients in predicting difficult intubation.

SECONDARY OBJECTIVE:

1.    To determine the predictive valueof these ultrasonographic measurements in determination of optimal endotrachealtube size.

2.    To examine the association betweenthese ultrasonographic measurements and airway clinical screening tests(interincisor gap, Mallampati grade and thyromental distance).

Examination of theairway is the most essential component of such preoperative evaluation, from ananaesthesiologist’s point of view. Difficulties in airway management largely contribute to increased mortality and morbidity for the patient.

Classically employed methods for airway examinationinclude measurement of inter-incisor distance and thyromental distance,estimation of Mallampati grade and assessment of the degree of neck flexion andextension. These tests are of limited use in evaluation of the pediatricairway owing to difference in anatomy of the pediatric airway when compared tothat of an adult and, failure to obtain a child’s cooperation in performingthese tests. A study done by Kopp etal showed that Mallampati score is a poor predictor of difficult laryngoscopyin paediatric patients.

Though multipleparameters exist for examination of the adult airway, there is limited data onmethods to assess the pediatric airway. Thus, relevant, simple and non-invasivemethods to evaluate pediatric airway are required to accurately assess thepatient’s airway pre-operatively and decrease the occurrence of unanticipateddifficult airway intraoperatively.