Objectives: The selection of an appropriate size of tracheal tube is important for airway management. For nasotracheal intubation, passing the nasal cavity should be taken into account for the selection of tube size. The aim of this study was to investigate the selection of appropriate size of nasotracheal tube in pediatric patients retrospectively. Materials and methods: The 1–12-year patients underwent dental procedures under general anesthesia intubated nasotracheally. The correlation between height, age, weight, the tracheal diameters at C6, C7, Th2 on the chest X-ray, and actually performed tube sizes were calculated. In addition, we compared the relationships between the predicted tube size and actually the intubated tube size. Results: The tube sizes intubated actually were between 4.0 and 6.0-mm ID. The formula by height could be most suitable for tube size. The correspondence rates for the tube with 4.5- and 5.0-mm ID were 78% and 53%. When they were predicted as 5.5- or 6.0-mm ID, 0.5 mm smaller size tube were intubated actually; 56% and 70%. When the predicted tube size was 4.0-mm ID, 0.5 mm larger size tube was intubated actually; 66%. Conclusions: The formula by height could be most suitable for the selection of size for pediatric nasotracheal intubation. When the predicted tube size was 5.5 or 6.0-mm ID, 0.5 mm smaller size should be chosen at first. In the case of 4.0-mm ID, 0.5 mm larger size should be chosen for first trial. Clinical relevance: The present data indicate that the selection of nasotracheal tube using the formula by height might be useful.
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