Ultrasound imaging in the preoperative estimation of the size of tracheostomy tube required in specialised operations in children

Abstract Background : Some children are dependent on a tracheostomy for many years. As they grow, larger tracheostomy tubes may be required. Although tables of sizes of tracheas exist for different age groups, they are estimations of normal and may not be accurate for atypical cases. Chest radiographs and computed tomograms (CT) have been used experimentally to estimate tracheal sizes, but are not in regular use. Method : High-resolution diagnostic ultrasound imaging was used to estimate the internal and external transverse tracheal diameter, and the depth of the trachea from the skin surface. This allowed selection of the correct standard pattern tracheostomy tube, or the construction of a custom-made tube preoperatively. Results : Four children with various abnormalities who were being considered for replacement tracheostomies were scanned. In one, diagnostic ultrasound confirmed that a new larger fenestrated tube could be placed, which subsequently improved vocalisation and respiration. In the other three, the scan showed there was no space to allow a larger tube to be placed. The standard tables were not suitable for any of these patients. Conclusion : High-resolution ultrasound has a role in the non-invasive measurement of the size of the tube needed for specialised operations in children.