Assessment of the subglottic region by ultrasonography for estimation of appropriate size endotracheal tube: A clinical prospective study

Background: Endotracheal intubation is important to carry out various surgical procedures. The estimation of endotracheal tube size is governed by narrowest diameter of the upper airway. The objective of the study was to assess the narrowest tracheal diameter by ultrasound for selection of the appropriate size endotracheal tube.Materials and Methods: After the approval of institution ethical committee and written informed consent, 112 patients aged 3 to 18 years of both genders with normal airways, scheduled for surgery under general anesthesia and intubation, were enrolled for this prospective clinical observational study. Preanesthetic ultrasonography of the subglottic region was performed by experienced ultrasonologist with a high-resolution linear array transducer in sniffing position for every patient and the subglottic tracheal diameter was estimated to select the appropriate-size endotracheal tube. The endotracheal tube, calculated on the basis of physical indices and by ultrasound, was statistically correlated with the appropriate size endotracheal tube used clinically for intubation.Results: The ultrasound guided selection criterion has estimated the appropriate-sized endotracheal tube better than physical indices (age or height)-based formulas. The estimated endotracheal tube size by ultrasound was significantly correlated with the clinically used endotracheal tube.Conclusion: Ultrasonography may be used for the assessment of the subglottic diameter of trachea in children to estimate the appropriate size endotracheal tube for intubation.