Pediatric Tracheal Dimensions on Computed Tomography and Its Correlation With Tracheostomy Tube Sizes P. Naina, DLO, MS ; Kamran Asif Syed, MS; Aparna Irodi, MD; Mary John, MS, PhD; Ajoy Mathew Varghese, MS Objective: Age-based formulas for selecting the appropriate size of tracheostomy tubes in children are based on data on tracheal dimensions. This study aims to measure the tracheal dimensions of Indian children by computerized tomography (CT) and to compare this with the dimensions of age-appropriate tracheostomy tubes. Methods: CT scans of children aged less than 16 years that were taken for indications other than respiratory distress were included. Tracheal diameters at the tracheostomy point and tracheal length from the tracheostomy point to the carina were calculated from the scans. These dimensions were correlated with age, weight, and height. The measurement on the CT scan was used to predict the appropriate size of tracheostomy tube, which was compared with the tracheostomy tube sizes. Results: Two hundred and fourteen CT scans of children aged below 16 years were included in the study. On multiple logistic regression analysis, tracheal diameter correlated well with age and weight (P = 0.04 and 0.001, respectively), whereas tracheal length correlated well with age and height of the child (P = 0.03 and 0 < 0.001, respectively). On comparison with dimensions of the tracheostomy tube, tracheal diameter correlated well, and the length was found to be longer than needed to prevent endobronchial intubation. The regression value was used to predict the size of an ideal tracheostomy tube. Conclusion: Tracheal diameter of Indian children correlates well with the outer diameter of age-appropriate tracheostomy tubes, but the length of these tubes is longer than the ideal length. This would necessitate a change in the design of these tubes. Key Words: Pediatric, tracheal diameter, tracheal length, tracheal dimensions, computed tomography, tracheostomy tube. Level of Evidence: 2b Laryngoscope, 00:1–6, 2019 INTRODUCTION The indications for pediatric tracheostomy have changed over the years. Currently, the most common indication is for prolonged ventilation, necessitated by neuromuscular or car- diorespiratory problems. 1 There has been an increasing trend toward the use of cuffed tubes in children due to the advan- tages offered in terms of better ventilation, less leak around the tube, and aspiration. 2,3 The choice of the correct size of tracheostomy tube is crucial for the appropriate manage- ment of these patients. The diameter of the tube should be large enough to allow ventilation without significant insuf- flation leak yet not so large as to cause ischemia of the deli- cate tracheal mucosa and subsequent scarring and tracheal stenosis. 4,5 The length of the tracheostomy tube is equally important. A tube that is too long may touch the carina and cause cough and bronchospasm. In rare cases, the tracheos- tomy tube can even go into the right bronchus with failure of ventilation and collapse of the left lung. 6 An ideal tracheos- tomy tube must fit the dimensions of the airway and the functional needs of the patient. The diameter should be bal- anced to avoid damage to the tracheal wall and to minimize the work of breathing, with a length no closer than 1 to 2 cm to the carina. 6,7 Most commonly, age-based formulas are used for deter- mining the size of the tracheostomy tube in children. 8–11 How- ever, these formulas are primarily based on studies done in Western populations. To the best of our knowledge, there is no evidence in favor of racial differences in the dimensions of the trachea. The aim of this study was to acquire normative data on tracheal dimensions in neck computed tomography (CT) of the pediatric population in India and to predict an appropriate tracheostomy tube size for our population. MATERIALS AND METHODS This study was done after obtaining the approval of the institu- tional review board (IRB no. 8992; dated 04.08.2014). CT scans of the neck of children under the age of 16 years who underwent imaging between June 2009 and June 2014 as part of the routine management protocol of their disease conditions were collected retrospectively. Neck CT scans of all children whose age at the time of imaging was less than 16 years and who had normal laryngotracheal anatomy as per the radiologist’s report were included. Electronic case records were retrieved to gather information on age, height, From the Department of ENT (P.N., K.A.S., M.J., A.M.V.); and the Department of Radiology (A.I.), Christian Medical College, Vellore, India. Editor’s Note: This Manuscript was accepted for publication on May 30, 2019. Presented as an oral presentation at ENT World Congress, Interna- tional Federation of Oto-Rhino-Laryngological Societies, Paris, France, June 29, 2017. First prize for best oral presentation at Institutional Research Day, Christian Medical College, Vellore, India, 2016. First prize for consultant paper presentation at Indian Academy of Otorhinolaryngol- ogy Head and Neck Surgery, Kolkata, India, 2016. The authors have no funding, financial relationships, or conflicts of interest to disclose. Send correspondence to Dr. P. Naina, DLO, MSK, Dept. of ENT, Christian Medical College, Vellore, Tamil Nadu, India, 632 004. E-mail: drp.naina@hotmail.com DOI: 10.1002/lary.28141 Laryngoscope 00: 2019 Naina et al.: Pediatric Tracheal Dimensions and Tracheostomy Tube 1 The Laryngoscope © 2019 The American Laryngological, Rhinological and Otological Society, Inc.