Evaluation of a new method for determining tracheal tube length in children.

Most paediatric tracheal tubes are marked in centimetres from the tip. In 105 children, nasotracheal tube length was set at the level of the vocal cords such that all 3.0 and 3.5 mm internal diameter tubes were placed with the 3 cm mark at the cords, all 4.0 and 4.5 tubes were set at 4 cm at the cords and all 5.0 and 5.5 tubes were set at 5 cm at the cords. Subsequent chest X ray showed that 79% of the tracheal tubes were in the ideal midtracheal position, one tube was marginally short and 20% of the tubes were marginally long. Neither bronchial intubation nor accidental extubation occurred in any subject. This is an effective method to determine tracheal tube length which may be used for both oral and nasal intubation.