Ultrasound assessment of the position of the tongue during induction of anaesthesia.

Tongue position was assessed in 15 female patients at induction of anaesthesia with either thiopentone or propofol. A video recording of a midline sagittal section of the tongue was made using an ultrasound transducer placed below the chin, and representative figures analysed by an observer who was not aware of the patient's state. In 11 satisfactory recordings, the tongue movement was inconsistent in direction and not more than 8 mm in the anterior tongue and 6 mm in the posterior tongue. The movements detected did not suggest that the tongue is likely to be an important cause of airway obstruction on induction of anaesthesia.