Prediction of Optimal Pediatric Endotracheal Tube Size "Aged Based Formula Versus Ultrasonography"

Background: Ultrasound (US) imaging technique has recently emerged as a novel, simple, portable, noninvasive tool helpful for airway assessment and management. Initial few published reports were on soft tissue imaging of neck, focusing on pre-tracheal structure and anterior tracheal wall. In our study, we compared the measurement of subglottic diameter using ultrasonography and the aged based formula in prediction of endotracheal tube size in children underwent elective surgical operation under general anesthesia. Methods: Patients were randomly divided in 2 groups (27 patients each) using a computer-generated randomization schedule. The first group was aged based group (group AB) (n = 27): the endotracheal tube size was determined according to age of the child \[inner diameter \[ID\] in mm = (age in yr/4) +4. The second group was ultrasound based group (group UB) (n = 27): the endotracheal tube size was determined according to the subglottic transverse diameter that was estimated with ultrasonography (the outer diameter of endotracheal tube (ETT OD) = 0.55\*(subglottic diameter)+1.16) .